Pre-transplant donor-specific HLA antibodies and risk for poor first year renal transplant outcomes - Results from the Swiss Transplant Cohort Study.

The aim of this study was to analyze first year renal outcomes in a nationwide prospective multicenter cohort comprising 2215 renal transplants, with a special emphasis on the presence of pre-transplant donor-specific HLA antibodies (DSA). All transplants had a complete virtual crossmatch and DSA were detected in 19% (411/2215). The investigated composite endpoint was a poor first year outcome defined as (i) allograft failure or (ii) death or (iii) poor allograft function (eGFR ≤25 ml/min/1.73m2 ) at one year. Two-hundred-twenty-one (221/2215; 10%) transplants showed a poor first year outcome. Rejection (24/70; 34%) was the most common reason for graft failure. First year patient's death was rare (48/2215; 2%). There were no statistically significant differences between DSA-positive and DSA-negative transplants regarding composite and each individual endpoint as well as reasons for graft failure and death. DSA-positive transplants experienced more frequently rejection episodes, mainly antibody-mediated rejection (both p<0.0001). The combination of DSA and any first year rejection was associated with the overall poorest death-censored allograft survival (p<0.0001). In conclusion, presence of pre-transplant DSA per se does not affect first year outcomes. However, DSA-positive transplants experiencing first year rejection are a high-risk population for poor allograft survival and may benefit from intense clinical surveillance.