Long-Term Effects of Antibodies against Human Leukocyte Antigens Detected by Flow Cytometry in the First Year after Renal Transplantation.

OBJECTIVE In this study, we aimed to investigate the incidence, dynamics and profiles of human leukocyte antigen (HLA)-directed antibodies developed after transplantation and their impact on graft rejection and outcome in kidney recipients. STUDY DESIGN Prospective follow-up study. MATERIAL AND METHODS A total of 56 kidney recipients were monitored at 1(st), 6(th) and 12(th) months for the development of anti-HLA antibodies using bead based flow-cytometry assays (Flow PRA tests). RESULTS In 21 (37.5%) patients, panel reactive antibodies (PRA) was positive after transplantation, however, in 35 (62.5%) patients PRA was found negative. Twelve (57.1%) patients with post-transplantation HLA-reactive antibodies [PRA (+)] and 8 (22.9%) patients with no detectable alloantibodies [PRA (-)] were developed allograft rejection (p=0.010). In the PRA positive patient group the rates of early period infection and delayed graft function (DGF) were higher than the PRA negative patient group. Serum creatinine levels of PRA positive group at 6. and 12. months after transplantation were significantly higher than the PRA negative group (p=0.015 and p=0.048, respectively). The rejection rates of patients who had class I and II HLA antibodies were significantly higher than the patients who had either class I or II HLA antibodies (p=0.011). Acute rejection rates were significantly higher in patients who had class I and II HLA antibodies at the first month (p=0.007). CONCLUSION Higher occurrence of rejection episodes in PRA positive group may show the importance of anti-HLA antibody monitoring using Flow-PRA after renal transplantation as a prognostic marker in terms of graft survival.