Changes in mental health among living kidney donors after donation: a a matched control study

Poster Sessions: Kidney

The World Transplant Congress 2014 Abstract Supplement

is jointly published by the American Journal of Transplantation and

Transplantation on behalf of the American Society of Transplant

Surgeons, The Transplantation Society and the American Society

of Transplantation.

© The Authors. Compilation © The American Society of Transplant Surgeons, The Transplantation

Society and the American Society of Transplantation

Kidney Antibody Mediated Rejection I

Sunday, July 27, 2014

6:30 PM - 8:00 PM

Exhibit

Hall

Abstract# A122

Role of Non-Donor Specifi c HLA Antibodies (NDSA) in Kidney

Transplant Rejection. K. Krum,

_{O. Fagoga,}

_{M. Doshi.}

_{Wayne State}

University School of Medicine, Detroit, MI;

_{University Lab, Detroit}

Medical Center, Detroit, MI.

Kidney transplant course is often complicated with development of Donor Specifi c Antibody (DSA) which have been associated with antibody-mediated rejection (ABMR) and poor allograft survival. However the role of Non-Donor Specifi c Antibody (NDSA) in occurrence of graft rejection and loss remains controversial. We studied patients who received a kidney transplant at Harper University Hospital from 2000-2010 and grouped them based on development of antibodies. The sera of patients were routinely screened for DSA and NDSA at 6 month to one year of transplant via ELISA or Luminex assay and only those with MFI >2500 were considered positive. The patients were evaluated for occurrence of biopsy proven acute rejection which was classifi ed as cellular or ABMR per Banff criteria. Graft function was determined by most recent blood creatinine levels as of 12-31-2012 and graft loss was defi ned as need to return to dialysis or re-transplant and was censored for death. Of the 200 patients included in the study, 63 (31.5%) had NDSA only, 10 (5%) produced DSA only, 25 (12.5%) produced both and 102 (51%) non-producers at an average of 7.9 months post-transplant (range: 1-18 months). The baseline recipient characteristics were comparable except that recipients producing NDSA only or both were more likely to have had a previous transplant and therefore had higher peak PRA than non-producers and DSA only, which is suggestive of preformed NDSA due to prior sensitization. Those who produced both were more likely to be on maintenance steroid as compared to non-producing, NDSA only, and DSA only (12% vs. 32.35%, 22.22%, and 30% respectively; p<0.05). The fraction of patients with greater strength of DSA and NDSA i.e. MFI >10K was higher in the combined group than those in NDSA only (80% vs. 51.28%; p=NS) and DSA only (66.7% vs. 0%; p<0.05). There was an increased incidence of ABMR in those who produced both as compared to non-producers, NDSA only, and DSA only (20% vs. 3.92%, 1.59%, 0% respectively; p<0.01), while there was no difference in cellular rejection rates among the groups (p=NS). While the serum creatinine at last follow-up was not different between the groups, the graft loss was higher in those that produced both than others. In conclusion, NDSA alone especially at MFI <10K are not associated with increased risk of ABMR or graft loss. It is unclear if higher levels of NDSA are detrimental, especially in presence of DSA.

Abstract# A123

Signifi cance of HLA IgM and IgM Donor Specifi c Antibodies in Renal

Transplantation. P. Dodd, M. Willicombe, P. Brookes, C. Roufosse, E.

Santos-Nunez, D. Goodall, C. Clarke, R. Charif, J. Galliford, A. McLean,

D. Taube. Imperial College Renal and Transplant Centre, London, United

Kingdom.

Pre-formed and de novo IgG donor specifi c HLA antibodies (DSA) are associated with acute and chronic antibody mediated rejection (AMR) and inferior renal allograft survival. However, some patients with AMR have no detectable circulating IgG HLA DSA and it is presumed that these antibodies are either absent or bound to the allograft. IgM HLA antibodies are traditionally thought to be harmless autoantibodies and there are few studies attributing a more pathogenic role for these antibodies in renal transplantation.

We retrospectively studied 24 recipients (17 male, 7 female, mean age 43.7 years), transplanted between 2004-2011, with allograft dysfunction and histological features suggestive of AMR but with no detectable IgG DSA. Indicative renal transplant biopsy revealed that 17/24 (70.8%) had evidence of either focal or diffuse C4d deposition, 14/24 (58.3%) had evidence of glomerulitis, 12/24 (50%) had evidence of tubulitis and 9/24 (37.5%) had evidence of peri-tubular capillaritis. Sera from these recipients, sampled pre- and post-transplantation including the time of indicative biopsy, were screened using LABScreen® Luminex® mixed and single antigen bead assays for the presence of IgG and IgM HLA and DSA. None of the 24 patients had third party IgG HLA antibodies or DSA prior to transplantation or at the time of indicative biopsy. However, 17/24 (70.8%) screened positive for the presence of IgM HLA antibodies and 12/17 (70.5%) were identifi ed as having Class I IgM DSA. Furthermore all patients with IgM antibodies identifi ed at the time of rejection had either third party IgM HLA antibodies (5/17) or IgM DSA (12/17) at the time of transplantation implying that these were pre-formed antibodies.

This study has 2 important fi ndings. Firstly, we show that a signifi cant proportion of patients with histological evidence of AMR and no detectable IgG HLA or DSA have Class I IgM HLA or DSA. Secondly, these antibodies were pre-formed at the time

of transplantation. This preliminary study implies that pre-formed IgM antibodies may not be harmless autoantibodies and that the presence of IgM DSA should be sought in patients with IgG HLA- or DSA-negative AMR.

Abstract# A124

Antibody-Mediated Rejections in ABO-Incompatible and Positive

Crossmatch Transplantations: A Similar Banff Phenotype But a

Different Outcome. L. Couzi,

_{M. Manook,}

_{R. Perera,}

_{O. Shaw,}

_A.

Zubir,

_{N. Kessaris,}

_{A. Dorling,}

_{N. Mamode.}

_{NHS Foundation Trust,}

Guy’s and St Thomas’ Hospitals, London, United Kingdom;

_Medical

Research Council Centre for Transplantation, King’s College, London,

United Kingdom.

Introduction: Positive crossmatch (HLAi) and ABO-incompatible (ABOi) transplantations are becoming increasingly common, but their results appear very different. To date, there are few data directly comparing these two groups. The aims of this study were to compare the results, and in particular antibody mediated rejection (AMR), of ABOi (n=69) and HLAi (n=27) renal transplantations. We also analysed a third group of patients who received a combined ABOi+HLAi transplantation (n=10). Patients and methods: 69 ABOi, 27 HLAi, and 10 combined ABOi/HLAi undergoing living-donor antibody incompatible transplants were included. All biopsies performed in the fi rst 100 days after transplantation were reviewed and scored according to Banff criteria.

Results: One-year death-censored graft survival was better in ABOi than in HLAi and ABOi+HLAi patients (99%, 80%, and 80%, p=0.0002). Five-year death-censored graft survival was still better in ABOi than in HLAi and ABOi+HLAi patients (99%, 69%, and 64%, p=0.0002). Induction therapy with T-cell depletion (ATG/Alemtuzumab) was more frequently used in HLAi and ABOi/HLAi patients, while rituximab was mainly used in ABOi patients. However, the incidence of both clinical and histological antibody-mediated rejection was not signifi cantly different between ABOi and HLAi (clinical: 16% vs 22%, p=0.5, histological 34% vs 52%, p=0.2); it was however higher in ABOi+HLAi patients (60% and 100%, p<0.05 versus ABOi and HLAi, respectively). After histological AMR, the percentages of patients experiencing a declining eGFR and graft loss were lower in ABOi than in both HLAi and ABOi+HLAi patients (declining eGFR: 29% versus 73% and 87%, p=0.05; graft loss: 6% versus 36% and 38%, p=0.04, respectively). This poor prognosis of AMR in HLAi and ABOi+HLAi transplantations was not explained by a higher severity of histological lesions (Semi-quantitative Banff scores were similar between the 3 groups).

Conclusion: The same AMR phenotype can lead to opposite outcomes according to the nature of the antigen and antibodies. An accommodation process could occur after AMR in ABOi transplantation while donor-specifi c HLA antibody commonly induces injury.

Abstract# A125

Bortezomib in The Treatment of Resistant Acute Antibody- Mediated

Rejection: A Single Centre Experience. J. Slatinska,

_{E. Svobodova,}

E. Honsova,

_{T. Marada,}

_{V. Hanzal,}

_{O. Viklicky.}

_{Department of}

Nephrology, Institute for Clinical and Experimental Medicine, Prague,

Czech Republic;

_{Department od Immunology, Institute for Clinical}

and Experimental Medicine, Prague, Czech Republic;

_{Department od}

Pathology, Institute for Clinical and Experimental Medicine, Prague,

Czech Republic;

_{Department of Surgery, Institute for Clinical and}

Experimental Medicine, Prague, Czech Republic.

INTRODUCTION AND AIMS: The aim of this retrospective single centre

study was to analyse effi cacy and safety of plasmapheresis (PP)/intravenous immunoglobulins (IVIG) vs. bortezomib (B) based treatment regimen in antibody mediated rejection (AMR).

METHOD: Medical records of 394 patients that had undergone kidney

transplantation between 1/2012-10/2013 were analyzed. AMR was defi ned as a C4d+ staining along with positive donor specifi c antibody (DSA) that occurred early after transplantation. In the group one AMR was treated using 5 cycles of PP followed by IVIG 0.2g/kg (n=12). The second group were patients with positive CDC a FACS after treatment (n=11), these patients received B [1 cycle of 4 doses of B (1.3 mg/m2)], PP and a dose of Rituximab (375mg/m2). Resistant AMR was defi ned as a persisting deterioration or non-function of renal allograft in patients with histological verifi cation of AMR, positive C4d+ staining and detection of DSA receiving standard antirejection treatment with PP + IVIG. Patients (pts) were followed for 3-12 months.

RESULTS:

AMR was diagnosed in 23 out of patients (5.8%) and occurred at 12 POD. There was a trend towards better 6 months patient survival in B group than in PF+ IVIG group (100 vs. 83.3%; p= n.s.). There were no signifi cant differences in donor age, panel reactive antibodies, HLA mismatches, length of dialysis therapy. The

All presenters are required to disclose relevant confl icts of interest.

All such disclosures are published within the Abstract Book following each abstract.

Any presenters who have nothing to disclose have been omitted from the disclosure listing.

number of retransplantation were signifi cant higher in B group (p= 0.02). Based on therapeutic effect, 4 pts received 1 cycle, 6 pts received 2 cycles and 1 patient was treated by 3 cycles of therapy. The side- effects observed were leucopenia (n= 8), thrombocytopenia (n= 11), fl uid retention (n= 6), polyneuropathy (n= 4). Using IVIG + PP vs. B regimes in treating acute AMR led to decrease in DSA. In HLA class I (PP+IVIG , p= 0.03, B group. p= 0.03) and class II (PP+IVIG, p = 0.02, B group, p= 0.01). In both therapeutical regimes we observed signifi cant improving of renal function- PP+ IVIG (S-Cr, p= 0.005), B regime (S-Cr, p= 0.005).

CONCLUSIONS: Combination of PP and B with Rituximab is an effective approach

to DSA decrease in cases of resistant acute AMR.

Abstract# A126

Outcomes of Concurrent Cellular Rejection in Patients With

Antibody-Mediated Rejection. B. Orandi, E. Kraus, S. Bagnasco, K.

Van Arendonk, J. Garonzik-Wang, R. Montgomery, D. Segev. Hopkins,

Baltimore.

BACKGROUND: Cell-mediated rejection (CMR) commonly complicates kidney transplantation (KT). Antibody-mediated rejection (AMR) is less common, but both are known to shorten graft survival independently. We sought to quantify the effect of developing both types of rejection on graft survival in the fi rst year post-transplant. METHODS: Using strictly defi ned criteria for AMR--including C4d-negative AMR--consistent with Banff 2013 guidelines, we identifi ed 199 AMR patients and reviewed their biopsies for CMR.

RESULTS: The overall incidence of AMR was 10.8%. Of 199 cases of AMR, most were in HLA-incompatible patients. 38.7% had no CMR (AMR+0), 14.1% had Banff type 1 CMR (1A+1B; AMR+1), 41.2% had Banff type 2 (2A+2B; AMR+2), and 6.0% had Banff type 3 CMR (AMR+3). Death-censored graft loss was signifi cantly higher in patients with combined AMR and CMR (P<0.001); however, that difference was driven largely by AMR+3 outcomes.

Excluding AMR+3 patients, there was no difference in outcomes between AMR+0 patients and AMR+1/2 patients.

DISCUSSION: Much of the differences seen in patients with AMR alone and AMR with CMR were driven by those patients with AMR+3. This diagnosis carries a poor prognosis and aggressive intervention is indicated for these patients. Patients with AMR+1 and AMR+2 did not seem to have higher graft loss than AMR+0 patients.

Abstract# A127

Subclinical Antibody Mediated Rejection in Kidney Transplantation:

Protocol Biopsy for De Novo Donor Specifi c Antibody, a

Single-Center Experience. D. Bertrand,

_{I. Etienne,}

_{F. Hau,}

_{D. Guerrot,}

_M.

Hanoy,

_{F. Le Roy,}

_{B. Legallicier,}

_{A. Francois,}

_{M. Godin.}

_Nephrology

Hemodialysis Transplantation, CHU Rouen- Hopital Bois Guillaume,

Rouen, France;

_{Etablissement Francais du Sang, CHU Rouen, Rouen,}

France;

_{Pathology, CHU Rouen, Rouen, France.}

The prevalence and treatment of subclinical antibody mediated rejection associated with de novo donor specifi c antibody (dn DSA) have not yet been well defi ned. Since october 2010, a renal biopsy was systematically performed in all newly detected dnDSA kidney transplant recipients. DSA were tested by routine surveillance 3, 6, 12 months then yearly after transplantation (Luminex single antigen). Demographic, clinical and pathologic data were collected.

Thirteen patients (24-46 years) were biopsied with a mean delay of 41,7 months after transplantation. Dn DSA were in all case a class II HLA antibody, and mean fl uorescence intensity (MFI) was 8026 (1874-17000). Graft function was stable in the last 3 months before biopsy (mean serum creatinin: 110 ± 20 μmol/L;Modifi cation of Diet in Renal Disease formula (MDRD): 64.4 ± 6.6 mL/min).

Pathologic fi ndings (Banff 2009 classifi cation) of renal biospies showed a mean microcirculation infl ammation score glomerulitis + peri tubular capilaritis (g+ cpt)

of 3.0 ± 1.6 and was ≥ 3 in 9 cases (70%). Peritubular C4d deposition was positive in 5 cases (38%). Transplant glomerulopathy was detected in 7 cases.

All patients with g + cpt ≥ 3 were treated with plasma exchange, rituximab, corticosteroids and intravenous immunoglobulins, followed by a repeat biopsy after a median follow-up of 4.6 ± 3.4 months. There was an improvement of microcirculation infl ammation score in 8/9 cases (2.5 ± 1 versus 3.9 ± 0.9; p = 0.0017). The MFI of the dn DSA decreased from 7836 to 4162 (p = 0.02). After a mean follow up of 19 months (11.6-35.6), mean serum creatinin increased from 108 ± 22 to 122 ±18 μmol/L (p=NS) (MDRD: 66.1±19 versus 54.2 mL/min ± 7.7, p=NS) with stable proteinuria (0.17 to 0.10 g/day; p=NS).

Pathologic fi ndings of renal biopsy performed for dnDSA detection without graft dysfunction very often show antibody mediated rejection lesions. Preemptive treatment is associated with improved microcirculation infl ammation score and decreased MFI of dnDSA. The real impact of such a strategy on long term kidney allograft function needs to be confi rmed by specifi cally designed studies.

Abstract# A128

To Treat or Not To Treat: Late Antibody Mediated Rejection in Kidney

Transplant Recipients. D. Diskin, T. Williams, R. Reed, J. Locke, R.

Mannon, R. Gaston, V. Kumar. Comprehensive Transplant Institute,

University of Alabama at Birmingham, Birmingham, AL.

Background: To determine likelihood of response to therapy in late antibody

mediated rejection (AbMR), we examined variables associated with graft loss in 100 low immunologic risk patients treated at a single center in 2009-10.

Methods: All patients had negative T & B cell fl ow crossmatches at transplant

(txp) without desensitization and were at least 3 months post-txp at diagnosis. All underwent a for cause biopsy (2007 Banff scoring, and those with cg scores >2 were excluded). Treatment included IVIg (2g/kg) and steroids (2g). Patient demographics, clinical characteristics, and Banff biopsy scores were evaluated.

Results: AbMR occurred 4.3 years post-txp. Baseline serum creatinine (Cr) was 1.5

mg/dl, and median Cr at diagnosis was 2.7 mg/dl. 60% of patients subsequently lost their grafts, at a median time from AbMR of 11.5 months (range 4-20.5). Serum Cr and urine prot/cr at diagnosis were associated with graft loss.

The probability of graft loss was nearly 100% among patients with a serum creatinine >4.3 mg/dL at diagnosis.

Other than the Banff t score in a subgroup of patients, no other Banff scores were associated with graft loss, including a summed chronicity score (ci, ct, cg).

Conclusion: Clinical variables at diagnosis are better predictors of subsequent graft

failure than histologic characteristics in patients with late AbMR, a fi nding that may be useful in designing treatment plans and counseling patients regarding prognosis.

Abstract# A129

Identifi cation and Long-Term Consequences of Antibodies Which

Bound C1q in 118 Kidney Transplant Recipients With Donor Specifi c

Antibodies. G. Gautier Vargas,

_{S. Caillard,}

_{A. Parissiadis,}

_{J. Olagne,}

C. Froelich,

_{P. Perrin,}

_{L. Braun,}

_{F. Heibel,}

_{C. Gachet,}

_{B. Moulin.}

1

_{Nephrology Transplantation, Hopitaux Universitaires, Strasbourg, Bas}

Rhin, France;

_{Histocompatibility Laboratory, Etablissement Francais du}

Sang, Strasbourg, France;

_{UMR S949-Inserm, Etablissement Francais}

du Sang, Strasbourg, France.

Introduction: Donor specifi c antibodies (DSA) play an important role in

antibody-mediated rejection (ABMR) and graft dysfunction. Newer antibody detection assay Luminex® is highly sensitive but not accurately predictive of clinical outcomes. A more precise characterization of potentially harmful DSA is still a matter of concern.

Patients and Methods: 118 recipients (8%) among 947 adult kidney transplant

followed in Universitary Strasbourg Hospital had a functional graft and DSA in 2011. We identifi ed DSA by Single Antigen Beads (SAB), and analyzed their potential to activate the complement by binding C1q using a Luminex® C1q assay (One Lambda). We correlate these results with the presence of ABMR, kidney biopsy morphological features, C4d staining and graft function.

Results: Median follow up of sensitized patients was 8.5±6.5 years (3 months to 31

years). 65/118 patients (55%) were sensitized before transplantation. DSA identifi ed by SAB were mainly class II (72%). 55 patients (47%) had antibodies that bound C1q (DSA C1q+). DSA C1q+ were de novo in 45 patients. Eighty of the 118 patients underwent one or several kidney allograft biopsies for cause (n=135). Mean delay between DSA apparition and kidney biopsy was 4.5±5.4 years.77 biopsies met criteria for ABMR, 29 with lesions of acute rejection and 48 with chronic lesions. 64% of patients with ABMR had DSA C1q+. 76% of patients who did not have ABMR had DSA C1q-. Microcirculation infl ammation and chronic lesions were more pronounced in patients with DSA C1q+ than in patients with DSA C1q-, particularly when biopsies were done more than 5 years after DSA occurrence (cg score 1.98±1.3 vs. 0.55±1.1, p=0.0001). C4d staining was positive in 64% of patients with DSA C1q+ and negative in 64% of patients with DSA C1q-. Patients with DSA C1q+ had a poorer graft function (SCr 164 ± 75μmol/l) compared to those with DSA C1q- (SCr 146 ± 57μmol/l).

Conclusion:DSA that bound C1q are mainly HLA class II and de novo DSA. Our

data suggest that these DSA, as determined by the C1q assay, are associated with greater risk of ABMR, severe chronic tissue injury and allograft dysfunction.

Abstract# A130

Assessment of Eculizumab (Anti-C5) Therapy For Treatment of

Severe Antibody-Mediated Rejection Episodes (ABMR). S. Jordan, J.

Choi, A. Vo, J. Kahwaji, A. Peng, R. Villicana, H. Mark. Comprehensive

Transplant Center, Cedars-Sinai Medical Center, Los Angeles, CA.

Introduction: ABMR is a severe form of rejection with intense allograft injury

mediated by complement. Eculizumab (anti-C5) is emerging as an important therapeutic agent for treatment of hemolytic uremic syndrome (TMA) and possibly for prevention of ABMR in highly-HLA sensitized patients (HS), but there are limited reports on effi cacy in treating severe complement-mediated ABMR episodes, often with features of TMA. Here we undertook a case study to determine effi cacy and safety of Eculizumab in treating patients with severe ABMR episodes unresponsive to standard treatment with IVIG + Rituximab (I+R) or with PLEX+I +R. Patients &

Methods: From 9/2012 to present, 9 HS patients who presented with severe declines

in renal function associated with DSA elevation and/or evidence of ABMR+ on biopsy. All were initially treated with I+R or PLEX+I+R without response. These patients were then treated with Eculizumab (1200mg) initial dose followed by 900 mg weekly X4-8 doses. We assessed patient & graft survival, renal function and DSA levels pre-ABMR, @ ABMR and post-ABMR treatment. Results: 7/9 patients had signifi cant DSA rebound after transplantation a/w ABMR+ while 2/9 patients had no evidence of DSAs at ABMR+ biopsy (presumed non-HLA-DSAs). Five of 9 did not receive (R) desensitization (DES) therapy, suggesting an important impact of (R) on preventing DSA rebound. No patient deaths were seen, but 2 graft losses (one severe early ABMR+ and one late ABMR 5 years post-transplant secondary to medication non-adherence). Five of 9 patients also had evidence of TMA and 4/5 recovered after Eculizumab. Renal function improved or stabilized in all patients with graft survival post-Eculizumab.

Conclusions: PLEX+ Eculizumab appears to be an important therapeutic option

for treatment of severe ABMR associated with rapid decline in renal function, especially TMA+. Rapid DSA rebound responses seen in 5/9 HS patients not treated with (R) DES appears a signifi cant risk factor for severe ABMR. Thus effective antibody reduction strategies pre-transplant should improve effi cacy of Eculizumab post-transplant.

DISCLOSURES: Jordan, S.: Grant/Research Support, CSL Behring,

Genentech-Roche.

Abstract# A131

Capillary C4d Deposition Predicts Inferior Renal Allograft Survival

Independently of Morphological Lesions Suggestive of

Antibody-Mediated Rejection. Z. Kikic,

_{A. Kainz,}

_{N. Kozakowski,}

_R.

Oberbauer,

_{H. Regele,}

_{G. Bartel,}

_{G. Boehmig.}

_{Internal Medicine III,}

MUW, Vienna, Austria;

_{Internal Medicine, Elisabethinen Hospital, Linz,}

Austria;

_{Clinical Pathology, MUW, Vienna, Austria.}

Background: Antibody-mediated rejection (AMR) is a major determinant of

long-term kidney transplant survival. In support of a role of both complement-dependent and -independent graft injury, typical (micro)circulation lesions suggestive of AMR were found to occur also frequently in the absence of C4d deposition in peritubular capillaries (PTC). Considering an important role of C4d-negative AMR, some authors have recently questioned the relevance of C4d as an independent rejection marker.

Methods: In this study, 855 of 1248 renal transplant recipients (transplantation

1999-2006) subjected to one or more indication biopsies were included. Overall, 1976 biopsies were re-evaluated for C4d staining patterns (immunohistochemistry) and distinct AMR features [glomerulitis, peritubular capillaritis, capillary microthrombi, severe intimal arteritis (v3), chronic glomerulopathy]. Endpoints were censored graft survival and eGFR slope. Results: While C4d in >10% of PTC was tightly associated with histological AMR features (96 of 115 C4d-positive recipients, p<0.001), such features were frequently found also in the absence of C4d staining (247 patients). Seven-year graft survival was worse in patients with positive C4d staining (52%) than in C4d-negative patients with (70%) or without (85%) AMR features, respectively (p<0.001). In multivariate models adjusting for multiple confounders including the presence or absence of AMR features, C4d staining turned out to be a strong independent risk factor of allograft loss (HR: 1.97, CI: 1.40-2.78, p<0.001). Spline models revealed that the additive risk of positive C4d staining was associated with the overall sum score of individual AMR features. While the presence of AMR features in early transplant biopsies (<6 months) did not signifi cantly affect transplant survival independently of C4d staining (HR: 1.41, 95% CI 0.99-2.00; p=0.055), late evidence of tissue injury turned out to be an independent risk factor for subsequent graft loss (HR: 1.71, 95% CI 1.12-2.62; p=0.013). Conclusion: Our data support the view that detection of intragraft complement activation may indicate a more severe course of AMR and suggest that C4d staining in indication biopsies is an excellent marker predicting inferior graft survival also independently of morphological AMR features.

Abstract# A132

Lack of C1q Reactivity in Post-LVAD Patient Sera. J. Pliszczynski, C.

Van Buren, A. Eaton, N. Woolley, J. Saltarrelli, E. McKissick, N. Acorda,

P. Erice, A. Hoover, C. Hollingsworth, J. Chapelle, C. O’Mahony, O.

Frazier, H. Mallidi, R. Kerman. Baylor College of Medicine, Houston, TX.

End stage heart disease can be treated with implantation of a mechanical circulatory support device, often to assist the left ventricle (LVAD) as a bridge to heart transplantation. During the LVAD operation patients may be exposed to large volumes of blood and blood products resulting in production of anti-HLA antibodies (Abs). This higher degree of HLA sensitization results in positive virtual crossmatches, eliminating many potential donors. However, when LVAD patients are transplanted they do not have a different rejection severity or frequency or poorer graft outcome than non-LVAD or non-sensitized heart transplant recipients. We hypothesized that while these LVAD treated patients display anti-HLA Abs these Abs may not be C1q reactive and therefore may not be functionally deleterious.

We evaluated 90 patients (61 male, 29 female, mean age of 54 years). Seventy-three patient sera were evaluated pre-LVAD and 17 patient sera post-LVAD for the presence of cI and cII HLA Abs and C1q reactivity using One Lambda, Inc. reagents and following manufacturers instructions.

The cI and cII PRAs pre and post LVAD were divided into three groups. For cI PRAs of 0–5% were seen in 57% of patients pre-LVAD vs. 59% of patients post-LVAD. PRAs of > 5–50% were seen in 23% of patients pre-LVAD vs. 29% of patients post-LVAD. Finally, PRAs of > 50% were seen in 20% of patients pre-LVAD vs. 12% of patients post-LVAD. Class II PRAs of 0–5% were seen in 83% of patients pre-LVAD vs. 59% of patients post-LVAD. Class II PRAs of > 5–50% were seen in 7% of patients pre-LVAD vs. 29% of patients post-LVAD (p≤0.05). Finally, PRAs of >50% were seen in 10% of patients pre-LVAD vs. 12% of patients post-LVAD. Pre-LVAD C1q reactivity was seen in 38% of patients with cI HLA Abs and 45% of patients with cII HLA Abs. However, in contradistinction to the pre-LVAD C1q positive reactivity only 8% of both cI and/or cII post-LVAD sera were C1q positive (8% vs. 38%, p<0.01; 8% vs. 45%, p<0.01)

These data suggest that while HLA antibodies are present in post-LVAD patient sera 92% of these antibodies tested as C1q non-reactive. This may explain why these identifi able HLA antibodies do not adversely impact LVAD treated heart transplant patients.

Abstract# A133

New Biomarker VEA195 as Early Serologic Indication of Organ

Transplant Rejection: Validation Study in Comparison With

Histomorphologic Data. F. Agbalika,

_{M. Carmagnat,}

_{D. Bengoufa,}

M. Stern,

_{F. Desgrandschamps,}

_{J. Verine,}

_{D. Charron,}

_{D. Glotz.}

1

_{Paris Diderot University, Paris, France;}

_{Hopital St Louis APHP, Paris,}

France;

_{Hopital Foch APHP, Suresnes, France.}

Background:

The identifi cation of new bio-marker to predict and to monitor the renal graft loss is a challenge to overcome, in spite of emerging roles attributed to alloantibodies to identify recipients at risk of rejection.

The aim of this study is to evaluate the detection and the quantifi cation of a 30 kD immune protein using its partial sequence, VEA195, considered as a serologic monitoring marker in kidney-allograft failure.

Materials and Methods:

1- Residual serum specimens of 31 allografted patients and 17 controls; including 15 blood donors based on ABO system and 2 non transplanted kidney failure patients. All sera were stored at -20°C after completion of routine biological analyses. All the patients were HLA-I and HLA-II total or partial mismatched recipients (living donors). An experienced renal pathologist independently confi rmed the rejection stage according to the Banff 05-07 criteria.

2- The detection of VEA195 was blindly performed by colloidal gold immunochromatography assay on membrane using two specific monoclonal antibodies 7G9 and 10E5.

3- The reactivity on a strip test was displayed by the presence of purple red test-band, visually appreciated at 40 ng/ml serum and automatically quantifi ed with lower limits of 2 ng/ml serum. This was completed in comparison with a standard curve previously established with serial dilutions of the VEA195 peptide on densitometer.

Characteristics of tested patients (n=48)

Transplanted patients Kidney Failure patientsBlood _Donors No Rejection Humoral Rejection Cellular Rejection Borderline

patients SLE Cryoglobulinemia ABO System 9 6 8 8 1 1 15 Visual VEA195 (lim= 40ng/ml)5+/4- 2+/4- 8+ 8+ 1- 1+ 15-Quantif VEA195 (lim= 2ng/ml) for positive pts 45-95 80-110 200-300 65-105 n/a 55 n/a Conclusions:

1- VEA195 is an early serologic marker of prediction in graft loss. Five of nine non-rejection patients were found VEA-reactive 6 to 9 months before rejection confi rmation by patho-histology assay.

2- In situ VEA 195 staining by specifi c monoclonal antibodies was also shown in glomerule and peritubular capillaries similarly to immunochemical staining of rejection on biopsies.

3- VEA195, circulating and staining on biopsy, is to be considered as molecular biomarker with potential development in the future therapeutic strategies in post-transplant rejection.

DISCLOSURES: Agbalika, F.: Stockholder, Biovialife inc.

Abstract# A134

Antibody Mediated Rejection(AMR) in the Absence of Donor Specifi c

Antibody(DSA) in HLA Sensitized Kidney Transplant Recipients. A.

Peng, J. Kahwaji, J. Choi, R. Villicana, A. Vo, S. Jordan. Comprehensive

Transplant Center, Cedars Sinai Medical Center, Los Angeles, CA.

BACKGROUND: As desensitization has become more widely implemented, the need to better classify AMR has become clear. The summary from the 12th Banff Conference on Transplant Pathology included a proposed AMR Classifi cation. For all AMR subclasses, serologic evidence of DSA (HLA or non-HLA) is required. We present a group of HLA sensitized patients with features of AMR but no recognized DSA at time of biopsy.

METHODS: From Jan 2005 to the present, 108 kidney transplant recipients were treated for AMR. We eliminated 26 who were not previously sensitized, 12 who had an ABO-I, 2 who had SPKs, and 12 who were treated empirically. We evaluated the remaining 56 patients for presence of DSA, including historical DSA, creatinine(cr), proteinuria, and graft survival. We compared DSA+ and DSA- AMR patients. RESULTS: Of 56 patients, 6 were identifi ed with no evidence of HLA DSA at the time of biopsy proven AMR.

Pt Tx DateHistorical _DSA Time to _AMR AMR Current Cr _(mg/dl) Current _proteinuria AT1R Ab

1 8/26/08 Y 5D Acute failed n/a

2 10/27/09 Y 2Wk Acute/Chronic 3.4 Y N

3 8/03/10 N 10M Acute/Chronic 1.4 N N

4 2/17/11 Y 33M Chronic 1.7 Y

5 1/05/12 Y 4M Acute/Chronic 2.1 Y

6 12/15/12 Y 6M Acute 1 N

All but one had historical HLA DSA, but none of the six had HLA DSA at the time of AMR diagnosis or thereafter. The cr at 1 and 3 yrs was 1.54 and 2 mg/dl respectively. At present 83% are functioning. Five of 6 had proteinuria at the time of diagnosis, with 60% ongoing. Of the 50 patients with DSA+ AMR, 68% still have a functioning graft. The cr at 1 and 3 yrs was 1.8 and 1.6 mg/dl. Forty percent of the DSA+ AMR patients had signifi cant proteinuria at diagnosis. Sixteen of the 40 patients with a recent urinalysis (40%) have ongoing proteinuria. Seven patients (14%) had resolution of DSA with treatment.

CONCLUSION: The current histologic diagnosis of AMR requires the presence of DSA. In our HLA sensitized patients, we found 11% without identifi ed DSA at the time of biopsy or thereafter. Most had historical DSA. One had no current or historical HLA DSA, AT1R antibody, or evidence of anti-endothelial cell antibody despite apparent AMR on biopsy. Such patients are presumed to have non-HLA DSA yet be identifi ed. No difference in outcomes between the DSA+ and DSA- groups was found. These results highlight the role of non-HLA DSA and the importance of considering a diagnosis of AMR even in the absence of known DSA.

DISCLOSURES: Jordan, S.: Grant/Research Support, CSL Behring.

Abstract# A135

C4d Negative Antibody Mediated Rejection(AMR) Has a Similar

Prognosis as C4d Positive AMR in Desensitized Live Donor Kidney

Transplant Recipients. R. Crew, S. Patel, S. Mohan, B. Stokes, J. Brown,

L. Ratner. Columbia University, New York, NY.

INTRO:AMR is characterized by graft dysfunction, donor specifi c antibodies(DSA),

microcirculatory infl ammation, and evidence of complement activation in peritubular capillaries(C4d). Many of our positive crossmatch patients have histologic features of AMR but are C4d neg. We reviewed our live donor +XM cohort to identify whether AMR outcomes differed by C4d pos and C4d neg status.

METHODS/RESULTS: We performed 58 +XM kidney transplants from 9/2004

to 12/2013. All received a minimum of two pre- and post- txp plasmapheresis with IVIG replacement (100mg/kg) and maintenance immunosuppression with tacrolimus, mycophenolate, and steroids. Induction therapy varied, and included either an IL-2 receptor blocker or Thymoglobulin® with or without intra-op rituximab, and IV methylpred with taper to pred 20 mg by post-op day 4. AMR was defi ned as graft dysfunction, PTCitis and +DSA testing by solid phase assay or XM. 30 +XM patients met these criteria for AMR as their fi rst rejection episode -- 15 were C4d neg and 15 were C4d pos.(see table) Both groups were similar in terms of age, gender, sensitization history, and CDC vs fl ow +XM. Time to rejection was shorter in the C4d neg cohort (6 vs. 10 days, p=0.01), however, response to treatment, cellular rejections, recurrent rejections, and renal function were similar between groups. More C4d neg AMR grafts failed, but this difference was not statistically signifi cant.

C4d neg C4d pos p value

N 15 15 NS Age(range) 44.1(26-67) 43.6(26-60) NS Males 47% 33% NS Prior pregnancy 75% 70% NS Prior txp 66% 53% NS LRRTx (vs LURTx) 53% 33% NS CDC +XM/Flow +XM only 9/6 9/6 NS

AMR with concomitant ACR 47% 27% NS

AMR + ACR grade

Borderline-1 ACR 1a- 1 ACR 2a- 5 ACR 1a - 1 ACR 1B - 2 ACR 2A - 2 NS Days to fi rst rejection (IQR) 6(5-7) 10 (6-14) 0.01

Creatinine at rejection 4.5 3.4 NS

Response to treatment 9 complete, 4 partial 10 complete, 4 partial NS

6 month creatinine 2.5 1.6 NS

1 year creatinine 2.3 1.6 NS

Mean days f/u(range) 1876(20-3212) 1323(85-3211) NS

Creatinine at f/u 3.4 2.3 NS

Graft failed 7 3 NS

Death with function 1 2 NS

CONCLUSION: Our data suggest that desensitized patients with AMR have similar

outcomes regardless of C4d staining. Patients with features of AMR and negative C4d stain should be considered for DSA testing. Diagnostic criteria of AMR may need modifi ed to include patients with negative C4d testing.

Abstract# A136

M2 Macrophages in Glomerular Infl ammation in Transplant Biopsies:

A Possible Role in Microvascular Remodeling. J. Papadimitriou,

_M.

Chaudhry,

_{A. Haririan,}

_{C. Drachenberg,}

_{D. Klassen,}

_{E. Ramos,}

_R.

Ugarte,

_{M. Mavanur,}

_{N. Costa,}

_{C. Cangro.}

_{Pathology, University of}

Maryland School of Medicine, Baltimore, MD;

_{Medicine, University of}

Maryland School of Medicine, Baltimore, MD.

Introduction: Macrophages constitute an essential component of innate immunity, but perform also many homeostatic functions, including tissue remodeling. The latter is associated with the M2 polarized macrophage phenotype, in contrast to the proinfl ammatory M1 polarized phenotype. The M2 polarized phenotype has been associated in other systems (tumor invasive growth) with disruption of the basal lamina/basement membrane. Since macrophages have been generally associated with antibody mediated rejection (AMR) microvascular lesions and portend a worse prognosis, a more detailed study into their subtypes was undertaken in order to better understand the pathophysiology of this process.

Materials and Methods: We performed CD206 immunstains for identifi cation of M2 polarized macrophages in renal transplant biopsies with documented increase in glomerular macrophages (>12 CD68 staining cells in the most infl amed glomerulus), provided that electron microscopic studies (EM) were available, in addition to the full histological work up routinely used for evaluation of transplant biopsies. 52 biopsies qualifi ed for this study.

Results: M2 polarized macrophages constitute a major component of the glomerular macrophages (73% on average). Their numbers correlate with the Banff glomerulitis (g, p=.049), chronic transplant glomerulopathy (cg, p=.012) and mesangial matrix deposition (mm, p=.05) scores. More importantly, M2 polarized macrophages correlate with the ultrastructural number of peritubular capillary basal lamina layers (a diagnostic feature of AMR specifi cally related to microvascular remodeling) (r=.41, p=.003) and time post-transplantation (r=.28,p=0.47).

Conclusions: Macrophages are a key morphological component of AMR and its characteristic microvascular pathology. Macrophages, however, display a wide functional and phenotypic spectrum. This study indicates that a major pathogenetic role in transplant glomerular/microvascular pathology is most probably played not by the powerful pro-infl ammatory function of these cells (M1), but rather by their smoldering, tissue remodeling -particularly microvasculature basal lamina dissolution/remodeling properties.

Abstract# A137

The Impact of Rituximab On Renal Allograft Outcomes in

Patients With Preformed Low Level Donor-Specifi c Antibodies. B.

Ravichandran, W. Manitpisitkul, M. Gillespie, N. Wilson, R. Ugarte, S.

Bartlett, A. Haririan. University of Maryland, Baltimore.

Background: Low levels of preformed donor-specific antibodies (DSA) are

associated with antibody-mediated rejection (AMR) and allograft loss. It has been suggested that addition of rituximab to thymoglobulin for induction is effective in reducing the risk of AMR in these patients. We evaluated the impact of rituximab on renal allograft outcomes in patients with low level DSA and negative crossmatch.

Methods: All patients with low-level DSA receiving a kidney transplant between

9/2006-3/2013 were included. In addition to standard induction agent, the majority of the patients received a dose of rituximab. Maintenance immunosuppression included TAC/MMF/Pred. Primary outcomes included acute cellular rejection (ACR), AMR, transplant glomerulopathy (TG), and graft survival.

Results: During the study period, 65 patients were identifi ed. Patient characteristics

are summarized in table 1.

Parameter Result Age 48.1±14.4 Male 40 (61.5) African-American 21 (32.3) Living Donor 64 (98.5) Previous Transplant 14 (21.5) HLA Mismatch 4.4±1.3 CMV Mismatch 14 (22.2) rATG 54 (84.4) Diabetes Mellitus 20 (31.3) Rituximab 47 (72.3) ACR,≥Borderline 15 (23.1) ACR,≥1A 8 (12.3) AMR 16 (24.6) Transplant Glomerulopathy 6 (9.2)

During 35.4±22.4 month follow-up, they underwent 172 biopsies. Overall, ACR was observed in 23.1% of patients, associated with worse graft survival (HR=8.4, p=0.005). Acute AMR occurred in 24.6% of patients, not predictive of worse graft survival (HR=2.27, p=0.27). ACR and AMR were observed in 12.8% and 23.4% of patients who received rituximab, compared to 11.1% and 28% who did not (p=NS), respectively. 6 cases with TG were diagnosed, 5 (10.6%) in the former and

1 (5.6%) in the latter group (p=NS). The overall graft survival rates at 1, 2, and 3 years were 98.2%, 93.7% and 88.2%, respectively. Rituximab was not associated with improved graft survival.

Conclusions: Our experience suggests that in patients with low level DSA at the time

of transplant, addition of Rituximab to standard induction therapy does not improve graft outcomes. Moreover, we found that ACR, but not AMR, was associated with worse graft survival.

Abstract# A138

De Novo C1q-Binding Donor-Specifi c Antibody (DSA) in Pediatric

Renal Transplant Recipients. J. Smith,

_{K. Nelson,}

_{P. Warner,}

_L.

Finn,

_{H. Pope,}

_{R. McDonald.}

_{Pediatrics, Nephrology, University of}

Washington, Seattle;

_{Immunogenetics/HLA, Puget Sound Blood Center,}

Seattle;

_{Pathology, University of Washington, Seattle;}

_{Wheaton College,}

Norton.

Background:

The ability to bind complement is thought to be associated with DSA which contribute to the development of antibody-mediated rejection. The objective of this study was to assess whether de novo DSA which bind complement were associated with changes in renal allograft histology.

Methods:

This retrospective cohort study was conducted at a single pediatric renal transplant center and included all fi rst, kidney alone, transplants since 2007. DSA testing was performed every 3 months using FlowPRA ® Single Antigen and LABScreen® Single Antigen using a threshold of 1000 MFI. Biopsies were performed at 3, 6, 12 and 24 months post-transplant and for cause. Retrospective testing for the ability of DSA to bind the complement component C1q (C1qScreen™) was performed for samples which were positive for DSA and associated with a biopsy. All biopsies were re-reviewed retrospectively by a pathologist using the Banff classifi cation of renal allograft pathology. This study analyzed the level of C4d deposition and the level of interstitial fi brosis and tubular atrophy (IFTA).

Results:

A total of 132 subjects had both DSA and renal allograft biopsies available for analysis. DSA was detected in 52 patients (39%): DSA which bound C1q (DSA-C1q) developed in 44 (33%) subjects. The concordance of C1q-binding DSA and biopsies positive for C4d is shown in Table 1. By 3 years post-transplant, almost 50% of biopsies were positive for C4d and associated with DSA which bound C1q. There were no biopsies positive for C4d with no C1q-binding DSA. In addition, 83% of the subjects with C1q-binding DSA had biopsies which showed moderate to severe IFTA compared to only 5% of subjects with DSA that did not bind C1q (p=0.08).

Conclusions:

De novo DSA which bound C1q was associated with C4d deposition and increases in IFTA in this cohort of pediatric renal transplant recipients.

Months Post-Transplant # of biopsies C4d+/C1q+ C4d-/C1q+

C4d-/C1q-1-12 m 66 6 (9%) 4 (6%) 56 (85%) 13-24 m 39 13 (33%) 4 (10%) 22 (56%) 25-36 m 29 10 (34%) 4 (14%) 15 (52%) 37-60 m 29 14 (48%) 3 (10%) 12 (31%) >60 m 29 15 (52%) 2 (5%) 12 (31%)

Abstract# A139

Incidence and Predictors of Renal Allograft Loss Following

Non-HLA Antibody Mediated Rejection. J. Brar,

_{B. Astor,}

_{L. Osadchuk,}

A. Djamali,

_{T. Ellis.}

_{Department of Surgery, Madison;}

_Department

of Medicine, Madison;

_{Department of Population and Health Sciences,}

Madison;

_{Department of Pathology and Laboratory Medicine, Madison.}

Purpose: To identify the incidence and risk factors associated with graft loss following non-HLA antibody mediated rejection.

Methods: The study population comprised 59 patients (32% females, 78% Caucasian) transplanted at our institution between 1/1/09-5/31/12 who developed biopsy-proven antibody mediated rejection (C4d positive, with or without peritubular capillaritis and/or glomerulitis) in the absence of detectable HLA-donor specifi c antibodies (DSA) by Luminex single antigen bead testing.

Results:

A total of 12 graft losses and 7 deaths occurred over a median follow-up time of 30.5 months. Both a 0% cPRA and occurrence of delayed graft function (DGF) predicted graft loss after adjustment for age and gender (Table 1). Associations of 0% cPRA, DGF(p=0.06) and >3 HLA mismatches with patient death approached signifi cance in univariate analysis. Of note, only 1 patient went on to develop subsequent detectable de novo DSA in this high risk group within a 1 year follow up period.

Risk Factor Hazard Ratio (95% confi dence interval) P value

Previous transplantation 6.1 (0.47,80) 0.16

0% cPRA 25.9 (1.4,263) 0.02

HLA mismatch>3 7.6 (0.67,64) 0.10

Delayed graft function 2.2 (0.94,12.3) 0.06

Conclusions: Despite the absence of detectable HLA-DSA by conventional single antigen bead testing, patients with biopsy-proven antibody mediated rejection remain at a substantial risk of graft loss. Further, the risk of graft loss in these patients is highest in those without detectable HLA allosensitization, suggesting a role for other non-HLA auto- or alloreactive antibodies in mediating graft injury, or possible local deposition of HLA-DSA that are not detected in the circulation.

Abstract# A140

IgG Donor Specifi c Antibodies [DSAs] in Patients With Transplant

Glomerulopathy [TG] Are Associated With Inferior Allograft

Survival. C. Clarke,

_{C. Lawrence,}

_{M. Willicombe,}

_{K. Shiu,}

_P.

Brookes,

_{C. Roufosse,}

_{T. Cook,}

_{A. Dorling,}

_{D. Taube,}

_{J. Galliford.}

1

_{Imperial College Renal and Transplant Centre, Imperial College NHS}

Trust, London, United Kingdom;

_{Renal, Urology and Transplantation}

Directorate, Guy’s and St Thomas’ NHS Foundation Trust, London,

United Kingdom.

Transplant glomerulopathy (TG) is a manifestation of chronic AMR with a poor prognosis and no specifi c treatment. Although the association between TG and anti HLA antibodies [Abs] is well known, there are few studies linking the nature of these Abs to outcome. 55 patients with TG (33M, 22F, mean age 47.5±12.1 yrs, mean time to TG diagnosis 9.32±8.37 yrs, mean follow up 26.6±18.0 months) were studied. Stored serum samples from the time of TG diagnosis were analysed for the presence of IgG and IgM HLA, DSA and Complement fi xing antibodies. 52/55 (94.5%) patients were HLA Ab+, 3/55 were IgG HLA Ab- and 1 patient was IgM HLA Ab+. 27/55 (49.1%) had IgG HLA DSAs, 2/27 had class I alone, 15/27 had class II alone and 10/27 had both class I+II. Overall 39/55 (69.1%) patients had Abs directed against DQ (21/39 were DSAbs, 18/39 were HLA). 24/55 (43.6%) patients had C1q+ antibodies; 2/24 (8.3%) had a C1q+ class I DSA, 16/24 (66.7%) had a C1q+ class II DSA, 3/24 (12.5%) had a C1q+ class I non DSA HLA and 3/24 (12.5%) had a C1q+ class II non DSA HLA. 16/24 (66.7%) of patients had C1q+ antibodies against DQ. Overall allograft survival was 70.8%, 35.3%, 27.2% and 15.5% at 12, 36, 48 and 60 months respectively, mean 26.4±17.7 months. Allograft survival was signifi cantly worse in IgG DSA+ patients compared with IgG DSA- patients.

(see Figure 1, log rank test p=0.04). The IgG DSA MFI had no effect on allograft survival. There was no difference in allograft survival in C1q+patients (p=0.88) although the presence of C1q+ Ab was associated with the presence of C4d on allograft biopsy (p=0.01).This study shows that the presence of IgG DSAs is associated with inferior allograft survival in patients with TG. This group of patients may benefi t from more aggressive therapy.

DISCLOSURES: Lawrence, C.: Other, Honoraria from OneLambda , speakers

fee from OneLambda.

Abstract# A141

Risk Factors and Clinical Outcomes in 3 Types of Acute

Antibody-Mediated Rejection After Kidney Transplantation. J. Kim,

_{K. Jun,}

M. Kim,

_{S. Ahn,}

_{B. Chung,}

_{J. Hwang,}

_{S. Kim,}

_{S. Park,}

_{B. Choi,}

_S.

Kim,

_{C. Yang,}

_{Y. Kim,}

_{M. Lee,}

_{I. Moon.}

_{Surgery, College of Medicine,}

The Catholic University of Korea, Seoul, Korea, Republic of;

_Internal

Medicine, College of Medicine, The Catholic University of Korea, Seoul,

Korea, Republic of.

Purpose

Acute antibody-mediated rejection (AAMR) has been increasingly recognized as a major cause of graft failure in kidney transplantation. The purpose of this study was to analyze prevalence, risk factors and clinical outcomes of acute antibody-mediated rejection.

Methods

We reviewed 835 patients who received kidney transplantation between January 2003 and April 2013. AAMR was diagnosed in 51 (6.1%) patients with median follow-up of 45.1 months (range 24 days-120 months). According to the type of AAMR, Recipients with AAMR were dived into three groups: ‘Type I’ (acute tubular necrosis like), ‘Type II’ (glomerular type), ‘Type III’ (vascular type with arterial infl ammation).

Results

Among the patients with AAMR, 6(11.8%) showed type I, 41 patients (80.4%) type II, and 4 patients (7.8%) type III. The mean serum creatinine levels at diagnosis, 7days, 1 month, 6 months and 1 year after treatment of AAMR were higher in patients with type III than in those with type I or type II, but did not differ signifi cantly (P = 0.357, 0.592, 0.716, 0.659 and 0.779, respectively). While all type I AAMR patients responded to treatment, 5 patients (12.2%) with type II and 3 patients (75%) with type III lost their allograft function. Graft survival rates at 1 year post-transplantation were 100%, in the ‘type I’ group, 97.6%, in the ‘type II’ group, and 25.0% in the ‘Type III’ group. There were signifi cant differences among the three groups in grafts survival (P<0.001), and in patients survival (P<0.001). There were no signifi cant differences among the three groups in the donor and recipient characteristics, and immunologic factors (number of HLA mismatch, number of KT, cross-match positivity, PRA>20%, PRA>50%, strong donor-specifi c anti-HLA antibody with a median fl urescence intensity (MFI) at diagnosis).

Conclusion

Compared with Type I & II AAMR, Type III AAMR had inferior graft and patient survival. But among the three groups, there were no signifi cant difference in patient characteristic and immunologic factors. Additional study is needed to fi nd out the strongest predictor for development of type III AAMR.

Abstract# A142

High Incidence of Rejection Caused By Donor Specifi c

Anti-HLA-DQ Antibodies in Kidney Transplant Recipients. A. Torio Ruiz,

_O.

Montes-Ares,

_{J. Rodriguez Perez,}

_{C. Garcia Canton.}

_{Immunology, C.}

H. U. Insular Materno Infantil, Las Palmas de Gran Canaria, Spain;

2

_{Nephrology, H. U. de Gran Canaria Dr. Negrin, Las Palmas de Gran}

Canaria, Spain;

_{Nephrology, C. H. U. Insular Materno Infantil, Las}

Palmas de Gran Canaria, Spain.

Objective: Anti-HLA antibodies post transplant follow up has been suggested by several studies as a useful tool to identify patients with acute or chronic rejection risk, and therefore useful to implement the necessary therapeutic measures that would help us minimize its clinical impact.

Materials and methods: We had carried out a transversal and prospective study of 342 kidney recipients. Anti-HLA antibodies were tested using Luminex technology, screening and single antigen (Genprobe). The median number of tests performed per patient was 3.3. Single antigen with MFI > 1500 and specifi city against any HLA donor antigen, determined by HLA-A/B/DR typing or linkage disequilibrium when HLA-DQB1* was not available, was assigned as donor specifi c antibody (DSA). Results: Post transplant anti-HLA antibodies were detected in 126 patients (37%): 31% (39/126) were antibodies HLA class I and II, 9.5% (12/126) were anti-HLA class I and 59.5% (75/126) were anti-anti-HLA class II. Within the 126 positive patients, 40 (31.7%; 40/126) were de novo and most of them anti-HLA class II (39/40; 97.5%). De novo anti-HLA class II antibodies were DSA in 35 patients (75%; 35/40), DQB1* was the most frequent specifi city (82.8%; 29/35), anti-DR was found in fi ve patients (17.2%; 6/35) most of them anti-anti-DRB4* (4/6). DSA anti-DR and anti-DQB1* was only present in one patient. Anti-DP antibodies were not considered as we lacked typing data. Fifteen patients from the group with de novo anti-DQB1* DSA (51.7%; 15/29) suffered a rejection episode, causing graft failure in fi ve recipients who failed to respond to therapy.

Conclusions: Anti-HLA antibodies monitoring allowed us to discover a high frequency of de novo anti-HLA class II DSA in kidney recipients, most of them against HLA-DQB1* specifi ties. These patients were found to have a higher rejection incidence. HLA-DQB1* typing should be recommended in donors and patients in order to take its compatibility into account.

Abstract# A143

Risk Factors for Graft Loss in Kidney Transplant Recipients With

Antibody Mediated Rejection and Three Consecutive Biopsies.

K. Cunningham, D. Hager, W. Zhong, B. Muth, T. Ellis, A. Djamali.

University of Wisconsin, Madison, WI.

Risk factors for graft loss in patients with ABMR are not well established. We addressed this question in a cohort of 31 patients diagnosed with ABMR who received renal transplants between January 2009 and March 2011. Patients underwent 3 consecutive biopsies post-transplant which allowed for assessment of pathological change over time. Of the 31 patients, 58% were male, 19% were African American, and the mean age was 44.7 ±14.8 years. The mean age of donors was 42.8 ±13.4 years, 3% were African American and 23% were living donors. Mean wait time to transplant was 532 ±552 days. Thymoglobulin represented 26% of induction regimens, alemtuzumab accounted for 3% and the remaining patients received basiliximab. There were 14 graft failures and 4 patient deaths among the 31 recipients. The average time to graft failure or last follow-up was 907 ±372 days.

Univariate cox regression analysis demonstrated that 6 month DSA >10,000 MFI and change in glomerulitis were associated with graft loss. Additionally, histologic characteristics on the second biopsy (tubulitis, intimal arteritis) and the third biopsy (interstitial infl ammation, mesangial matrix increase, interstitial fi brosis, tubulitis, tubular atrophy) were also associated with graft loss.

Multivariate stepwise cox regression analysis demonstrated that 6 month DSA >10,000 MFI after the fi rst biopsy (HR 6.40, [1.43 to 28.6], P=0.01) and interstitial fi brosis on the third biopsy (HR 2.54, [1.37 to 4.71], P=0.003) were the variables most associated with graft loss.

Covariate Univariate for Graft Loss Multivariate for Graft Loss

P HR 95% CI P HR 95% CI

Biopsy 1 6M DSA >10,000 0.009 6.40 1.57 to 26 0.01 6.40 1.43 to 28.6 Biopsy 2Intimal Arteritis_Tubulitis 0.01 2.33 1.2 to 4.6_{0.03 1.85 1.07 to 3.22} X_X X_X X_X

Biopsy 3

Interstitial Infl ammation 0.02 1.73 1.10 to 2.71 X X X Mesangial Matrix Increase 0.05 2.96 0.99 to 8.87 X X X Interstitial Fibrosis 0.002 2.14 1.34 to 3.41 0.003 2.54 1.37 to 4.71

Tubulitis 0.03 1.76 1.05 to 2.95 X X X

Tubular Atrophy 0.05 2.00 1.24 to 3.22 X X X Change in Glomerulitis 0.03 0.03 0.185 to 0.918 X X X

Risk factors most associated with graft loss in renal transplant patients with ABMR that underwent 3 consecutive biopsies were interstitial fi brosis on the third biopsy and persistent DSA after the fi rst biopsy. Further studies are needed to determine if specifi c therapies that reduce DSA after the fi rst episode of rejection can improve long-term outcomes.

Abstract# A144

Increase in Spot Urine Protein-Creatinine Ratio Before Kidney

Graft Rejection: A Marker to Predict Rejection Phenotype and

Graft Outcome. M. Arnol,

_{M. Oblak,}

_{J. Buturovic-Ponikvar,}

_D.

Ferluga,

_{N. Kojc,}

_{A. Kandus.}

_{Department of Nephrology, University}

Medical Centre, Ljubljana, Slovenia;

_{Faculty of Medicine, University}

of Ljubljana, Ljubljana, Slovenia;

_{Institute of Pathology, Faculty of}

Medicine, University of Ljubljana, Ljubljana, Slovenia.

Background. A noninvasive screening that foretells acute rejection before loss

of kidney graft function might reduce rejection-associated graft damage. We hypothesized that changes in spot urine protein-creatinine ratios (PCR) before acute rejection predict rejection phenotype and graft outcome.

Methods. Patients who underwent kidney transplantation between Jan 2000 and

Dec 2012 and provided biopsy samples for acute rejection were included. PCR were measured in morning spot urine at baseline (PCRbaseline) and 3 months before

biopsy (PCR-3m). We investigated whether changes in PCR between baseline and

3 months before rejection (DPCR=PCR-3m–PCRbaseline) were predictive of distinct

rejection patterns and graft loss.

Results. In the observed period 616 patients were transplanted, of whom 103 (17%)

had acute rejection >3 months post-transplant. The median ΔPCR was 20 (IQR 8 to 38) mg/mmol and median percent ΔPCR was 100 (IQR 40 to 226)%. The absolute and relative ΔPCR progressively increased with higher pathohystological degree of rejection.

Rejection phenotype ∆PCR, median

(IQR), mg/mmol

Percent ∆PCR, median (IQR), %

Area under the ROC curve (95% CI)

T cell, borderline

(n=9) 10 (4−19) 31 (0−56) 0.30 (0.17−0.42) T cell, no vasculits

(n=51) 13 (5−25) 53 (27−131) 0.68 (0.56−0.79) T cell, with vasculits

(n=14) 17 (11−30) 122 (47−154) 0.62 (0.52−0.73) Antibody-mediated or

mixed (n=29) 62 (28−158) 283 (130−604) 0.82 (0.74−0.91)

Receiver operator characteristics analysis demonstrated that ΔPCR had good diagnostic accuracy to predict antibody-mediated rejection (area under the curve 0.82) and ΔPCR >120% had the best sensitivity and specifi city (82% and 70%, respectively). After a median follow-up of 6.2 years, 29 patients lost their graft. The incidence of graft loss was higher in patients with ΔPCR >100% (40% vs. 16%,

P=0.005). In multivariate analysis, patients with ΔPCR >100% had an increased risk

of graft loss (hazard ratio 3.4, 95% CI 1.2–9.6; P=0.019), independently of recipient and donor age, graft function, and rejection phenotype.

Conclusion. An increase in proteinuria before acute kidney graft rejection is a

predictive marker of antibody-mediated or mixed rejection and could be used as a surrogate marker for poor outcomes.

Abstract# A145

Early Diagnosis and Treatment for Biopsy-Proven Subclinical

Chronic Antibody Mediated Rejection After Renal Transplantation. T.

Yamamoto, Y. Watarai, T. Kobayashi, A. Takeda, M. Tsujita, H. Takahisa,

N. Goto, S. Narumi, K. Morozumi, K. Uchida. Kidney Center, Nagoya

Daini Red Cross Hospital, Nagoya, Japan.

Introduction: De novo donor-specifi c antibodies (dn DSA) production after renal

transplantation has been reported to be associated with chronic antibody mediated rejection (CAMR). However, it is unclear whether all DSA can cause CAMR and what specifi city of HLA antibodies is responsible for CAMR have been raised. The aim of our study was to evaluate the predictors of subclinical CAMR (stably functioning kidney grafts with dn DSA) compared with latent antibody mediated response(no tissue injury with dn DSA) and to evaluate the effect of early treatment for subclinical CAMR.Methods: We studied 840 consecutive renal transplants without pretransplant DSA. These patients were screened for the presence of HLA-DSA by Luminex-mixed yearly. Among 77 DSA-positive patients (9.2%), renal graft biopsies were performed on 30 patients with positive levels of DSA and stably functioning grafts. After biopsies were performed, the patients who diagnosed subclinical CAMR were performed treatment (MMF addition or revision followed administer rituximab and two times DFPP). Results: Of the 30 patients who underwent graft biopsy, 4 patients were positive for class I DSA and 26 patients for class II DSA. Subclinical CAMR was diagnosed in 14 patients (46.7%) among the 30 patients, all of whom were strongly associated with DSA against HLA-DR. The predictors of subclinical CAMR compared with latent antibody mediated response were increased DSA-MFI (p<0.01), past history of acute rejection ((p<0.05) and existing dn DSA-DR associated (DR+DQ,DR alone)(p<0.01). Among 14 patients diagnosed subclinical CAMR, 9 patients were performed the treatment. Mean+/-SD values of DSA-MFI were 12803+/-8368 before the treatment and 10968+/-8482 at 6 month after it. No signifi cant changes were observed by this treatment for subclinical CAMR. Conclusion: The patients with dn DR associated DSA, increased DSA-MFI and past history of acute rejection are related to high risk of developing subclinical CAMR. Early treatment with MMF addition or revision followed administer DFPP and rituximab for subclinical CAMR was not possible to obtain a suffi cient effect.

Abstract# A146

Elimination of Unacceptable HLA Antigens When Present in

Transplant Patient Sera at an Undiluted or Neat Titer But Not Present

at a Low Titer (≤ 1:16). J. Saltarrelli, C. O’Mahony, E. McKissick, N.

Acorda, A. Eaton, N. Woolley, P. Erice, A. Hoover, C. Hollingsworth,

J. Chappelle, C. Van Buren, R. Kerman. Baylor College of Medicine,

Houston, TX.

HLA antibodies (Ab) are routinely identified in transplant recipient sera. Characteristics determining clinically deleterious Abs include specifi city, MFI and C1q. These factors are also used when identifying unacceptable HLA antigens (Ags). However, if unacceptable HLA Ab specifi cities are present in undiluted sera but not present when the sera is diluted 1:16 then these Ab specifi cities can possibly be ignored when deciding on which unacceptable Ab specifi cities to report. This reduction in unacceptable antigens would allow for an easier matching of highly sensitized patients to an appropriate donor for transplant.

Thirty-nine cI/cII high PRA sera were evaluated for the presence of HLA Abs and their antigen specifi cities at neat and at a 1:16 titer. The number of Ab specifi cities were compared at the two dilutions. One Lambda, Inc. reagents were used per the manufacturers instructions.

The HLA cI/cII PRAs were 77±25% and 84±21% respectively for the 39 sera. The total number of HLA cI/cII Ags identifi ed in undiluted sera were 46±22 and 34±22 respectively per patient. In addition, there were 7±8 cI and 5±4 cII falsely identifi ed HLA Ags respectively per patient. When sera were titrated to a 1:16 dilution 71±25% of cI and 51±28% of cII unacceptable Ags were absent. The total number of cI Ags eliminated were 21±10 and cII Ags were 15±9. When false positive Ags were included in the evaluation the frequency for Ag elimination at a 1:16 dilution for cI became 85±14% and 66±24% for cII respectively. Fifty-four patients with donor specifi c antibody (DSA) titers of ≤ 1:16 were identifi ed. 81% (44/54) had both negative cytotoxic (AHG) and fl ow cytometric (FCXM) donor specifi c crossmatches whereas 10 patients (19%, 10/54) displayed a negative AHG but a positive FCXM. When transplanted, the FCXM negative patients had a two year graft survival of 91% vs. 60% for the FCXM positive patients (p < 0.01).

These data suggest that titration studies of high PRA, multiple Ab specifi city presenting sera can be used when identifying unacceptable Ags. Moreover, the presence of DSA in low concentration (≤ 1:16) while falsely suggesting a positive