THE IMPACT OF HLA MATCHING ON GRAFT SURVIVAL AND ON SENSITIZATION AFTER A FAILED TRANSPLANT

Abstract

There are costs (both financial and ethical) to distributing kidneys by HLA match (time, transportation, repeat crossmatch; possibly bypassing a more deserving recipient). Arguments favoring matching include better short- and long-term survival, and decreased panel-reactive antibody (PRA) if a well-matched vs. poorly matched transplant fails. We studied these phenomena in a single institution. Since 1970, 1329 patients received cadaver (CAD) transplants; for those with defined antigens (n=1316) there was no difference in 10-year graft survival in those with a 1 AB match vs. those with >1 AB match or those with ±1 AB mismatch (mm) vs. >1 AB mm. Similarly there was no difference in those with 2 BDR mm vs. >2 BDR mm. In fact, those with < ABDR mm had worse 10-year graft survival (55%) than those with ±3 ABDR mm (61%) (P=.001). For patients with function >6 months there was no difference in long-term outcome based on HLA match or mm. These findings were similar for patients both with and without CsA immunosuppression, and for primary and retransplants. A total of 382 patients transplanted since 1980 have lost their grafts (146 died with function). All had received pretransplant transfusions. Of 236 alive after graft loss, 64 had no postgraft failure PRAs (22 out of state, 23 chose to remain on dialysis, 19 died less than 3 months after graft loss); 172 had PRAs after failure; 106 (62%) have been retransplanted. Mean peak PRA in those retransplanted was 23±31 (range 0–100) vs. 46±39 (range 0–100) in those not retransplanted (P<.05). Patients were stratified by PRA prior to first transplant (0%, 1–20%, >20%). For recipients with 0% PRA, failure of a CAD transplant (n=58) was no more likely to result in an increase of PRA than failure of a living-related donor (LRD) transplant (n=49) (NS). For those with an increase, mean increase was 45%±34 after LRD transplant and 41%±28 after CAD transplant (NS). The proportion developing PRA ±60% was not different after a failed LRD (7/49) or CAD (11/58) transplant (NS). Other subgroups had similar results. AZA or CsA immunosuppression did not affect development of increased PRA after a failed graft. For those with a failed CAD transplant, there was no difference in increase in PRA between those with ±1 AB match vs. >1 AB match, ±2 AB mm vs. >2 AB mm, ±1 AB mm vs. >1 AB mm, ±2 BDR mm vs. >2 BDR mm, ±3 ABDR mm vs. >3 ABDR mm. We find no benefit to distributing kidneys based on HLA match. PRA increases in some patients after a failed transplant; this increase is independent of the donor source and of the degree of ABDR match or mismatch.