HLA-Specific Antibodies Developed in the First Year Posttransplant are Predictive of Chronic Rejection and Renal Graft Loss

Background. Evidence shows posttransplant antibodies lead to renal allograft failure, but does the time elapsed between transplantation and antibody development impact allograft survival? This is the first study showing importance of when antibodies appear. Methods. Serial sera were collected during 17 years (1991-2008) from two groups of patients, one whose allograft failed due to chronic rejection containing 25 patients (230 sera) and a control group consisting of 25 graft functioning patients (305 sera) who were matched by transplant date to a patient whose graft failed. Results. The median follow-up for failure patients was 7.1 +/- 4.8 years and 11.8 +/- 4.4 years for controls. Human leukocyte antigens alloantibodies appeared in 24 of 25 (96%) of the failed patients and 48% of the controls (P < 0.0001). Time to antibodies also differed between groups. Fifteen (60%) patients from the failure group developed antibodies by I year compared with none in the control group. Hazard ratio of antibodies present in 1-year posttransplant from multivariate analysis for allograft loss was 7.77 (P < 0.001). Ten-year renal allograft survival in early antibody developers (< 1 year) was 27% vs. 80% in the late antibody developers. Conclusions. Overall, human leukocyte antigens antibody development within 1-year posttransplantation markedly lowers allograft survival compared with later antibody development. Therefore, monitoring early antibodies is useful.