The Impact of De Novo Donor-specific Anti-Human Leukocyte Antigen Antibodies on 5-Year Renal Transplant Outcome

Numerous studies have shown that circulating donor-specific antibodies targeting human leukocyte antigen (HLA) are associated with accelerated renal transplant failure, but many patients with these antibodies have good graft function. The aim of our study was to investigate the long-term graft function and survival in patients with de novo post-transplant donor-specific anti-HLA antibodies (DSA). Our prospective study included 78 consecutive recipients with a negative crossmatch before transplantation. Recipient serum samples were assayed for DSA in week 2 and 1, 3, 6, 9, 12 months after transplantation using a complement-dependent lymphocytotoxic technique with donor lymphocytes. Additionally, patients with DSA and stable renal function in the first year were tested with a more sensitive flow-panel-reactive antibody. DSA were present in 34 (44%) of our patients during the first 12 months after transplantation. Biopsy-proved acute rejection occurred in 11 DSA-positive and 10 DSA-negative patients. Seven DSA-positive patients had antibody-mediated rejection and no DSA-negative ones developed humoral rejection. The serum creatinine level in DSA-positive patients was significantly higher (2.48 vs 1.43 mg/dL) in year 5. The 13 (38%) DSA-positive patients with good graft function in month 12 were stable during a 5-year follow-up: their serum creatinine was 1.46 +/- 0.4 in year 1 and 1.56 +/- 0.4 mg/dL in year 5 and nobody lost their allograft. One- and 5- year graft survivals were appropriately 85% and 59% in DSA-positive patients compared to 93% and 93% in DSA-negative patients. To sum up, post-transplant DSA had a significant influence on kidney function and graft survival but in 38% of patients the presence of DSA did not decrease a 5-year renal function. A good renal allograft function in the presence of DSA in the first year after transplantation and cessation of their production in the subsequent years may be a good prognostic marker for a long-term allograft function and survival.