Relationship of donor-specific class-I anti-HLA antibodies detected by ELISA after kidney transplantation on the development of acute rejection and graft survival

Background. The objective of this study was to evaluate the role of post-transplant donor-specific anti-HLA antibodies (DS-HLA Abs) detected by an ELISA method on long-term graft survival. Methods. The serum pre-/post-transplant profile of anti-HLA Abs was analysed in 71 renal transplant patients by ELISA. The HLA specificity of positive sera was analysed by a different ELISA method. According to the results, patients were classified into two different groups: those who either developed DS-HLA Abs or significantly increased their panel-reactive antibody (PRA) (group A) and those who did not (group B). Results. Thirteen out of 71 patients showed posttransplant DS-HLA Abs and were included in group A, whereas the remaining 58 were placed in group B. The incidence of acute rejection (AR) was significantly higher in group A than in group B (77 vs 10%). In addition, seven out of eight patients from group A had graft loss secondary to AR, whereas one of nine grafts lost in group B was due to AR. When analysing the clinical outcome according to HLA class specificity, only patients with HLA-I Abs lost their grafts due to vascular AR. The remaining patients with HLA-II Abs who lost their grafts also had HLA-I Abs. In four of the eight patients who lost their grafts, DS HLA-I Abs were detected several days before AR. Conclusions. The detection of DS HLA-I Abs in the post-transplant period may provide a good marker for AR and graft loss due to immunological origin. Monitorization of these Abs by ELISA may be a useful tool for tailoring immunosuppression after kidney transplantation.