HLA MISMATCHING AND OUTCOME IN HEART, HEART-LUNG, AND SINGLE-LUNG TRANSPLANTATION

Background: To determine the influence of HLA mismatching on rejection after cardiothoracic organ transplantation, we analyzed results in 24 3 recipients. Methods: There were 183 heart, 25 heart-lung, and 35 sin gle lung recipient, all receiving triple-drug immunosuppression with a nti-thymocyte globulin induction. Zero, one, and two mismatches occurr ed by chance at each locus in between 0% to 9%, 26% to 35%, and 47% to 70% of recipients, respectively. Results: In heart recipients, compar ed with a two mismatch, a zero mismatch was associated with a lower li nearized rejection rate in the first 6 months. A zero B locus mismatch was likewise associated with less rejection in month 1, and DR zero m ismatch with reduced rejection in the first 3 months. Steroid withdraw al was more successful in those with zero mismatch at any locus. In he art-lung recipients linearized rejection was significantly lower in th ose with lesser degrees of A and DR locus mismatching, and after singl e-lung transplantation linearized rejection was significantly lower wi th lesser degrees of A and B locus mismatching from 3 to 6 months only . Actuarial survival did not differ for any organ with any degree of m ismatch at any locus. Conclusions: HLA mismatching affects rejection, but the effect is limited to the early postoperative period for heart and heart-lung recipients. Lower grades of mismatch increase the likel ihood of successful steroid withdrawal for heart recipients. The chanc e occurrence of no mismatch at any locus is rare, making prospective m atching infeasible. HLA mismatching identifies patients at higher risk of rejection. The best use of this information may be to guide early immunosuppression, limiting prospective matching to retransplants or w ith presensitized recipients.