172-P: MYSTERIOUS “SUBOPTIMAL” FUNCTION OF A DECEASED DONOR (DD) RENAL ALLOGRAFT

Abstract

Aim To determine the role of alloimmune status of a deceased donor renal allograft with suboptimal graft function. Methods HLA typing was done by rSSOP and antibody assays were done by LabScreen mixed (LSM), LabScreen ID/Flow PRA, Luminex Single Antigen Bead assays (SAB), and by DSA assay using beads coated with donor lymphocyte lysates (GenProbe). Crossmatches were done by Flow cytometry (FC). Biopsy was assessed by histology and C4d staining. Results The recipient had no Class I, II or MICA antibodies from Feb ‘08 till Feb ‘12 when B∗44:02 and A80 antibodies were detected by SAB. Serum from Mar ‘12 was negative for HLA Class I, II, and MICA by SAB. Quarterly sera from April ‘12 till Feb ‘13 had no HLA or MICA antibodies using LSM and or LabScreen ID and transplant was done from a DD in April’13 based on negative T-B FC using mouse monoclonal antihuman-IgG FITC using Feb’13 serum. The recipient had suboptimal graft function. Retro crossmatches and antibody assays with Mar and April ‘13 sera showed B∗44:02 DSA and both sera were T-B FC positive using splenocytes from the DD and blood lymphocytes from surrogate donor with Goat Antihuman IgG FITC. Using beads coated with lymphocyte lysates from the DD and surrogate, both sera had Class I DSA. The patient was treated based on DSA but the creatinine level remained abnormal. A biopsy ruled out immune mediated rejection. The DSA persists and the creatinine remains abnormal. In comparison, a living donor transplant (LD) recipient with no DSA, negative FC at the time of transplant, developed an A2, B∗44:03, DR7 and DR15 (recall DSAs) 7 days post transplant and suffered a C4d positive AMR. Conclusions The suboptimal graft function remains unclear in the DD case. The DSA assay with cell lysates might be useful to assess “actual DSA”. Both DD and LD cases show relevance of historic antibodies. The DD case needs follow-up to understand if alloimmunity is associated with the observed sub-optimal graft function.