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-upost-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 DSHLA 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.