Early rejection episodes.

1. Early rejection episodes had an overriding effect on graft survival. One-year graft survival decreased by 18% in LRD transplants and by 27% in cadaver-donor transplants when rejection occurred. Early rejection-free patients had 96% (LRD) and 87% (cadaver-donor) 1-year graft survival. 2. Among rejection-free recipients of first cadaver transplants, 1-year graft survival decreased by 5% when function was delayed for 8-14 days and by 10% when function was delayed more than 14 days, suggesting some rejections were masked by early nonfunction. 3. Rejections occurred in 30% of first cadaver donor transplants overall and ranged from 9-50% at individual contributing centers. Rejections occurred in 27% of LRD transplants and 37% of cadaver retransplants. 4. Histocompatibility affected the frequency of rejection as well as subsequent graft survival. The lowest incidence of rejection was 17% in HLA-identical sibling transplants, followed by 0 HLA-B,DR mismatched first cadaver transplants, with a progressive increase to 34% in completely mismatched (HLA-B,DR) first cadaver transplants. Parent and 1-haplotype sibling donor transplants were intermediate with a 30% incidence of rejection. In first cadaver transplant recipients with rejection, graft survival decreased from 78-59% with the degree of HLA mismatch. 5. Pretransplant transfusions also reduced the rejection frequency from 42% without to 24% with more than 4 transfusions.(ABSTRACT TRUNCATED AT 250 WORDS)