Predictive value of enzyme-linked immunosorbent assay-detected IgG anti-HLA antibodies for pediatric renal allograft rejection.

Abstract

Measurement of panel-reactive antibody (PRA) with an enzyme-linked immunosorbent assay using soluble HLA class I molecules (PRA-STAT) in adult renal transplant recipients predicted graft loss and rejection. We sought to confirm this finding in pediatric recipients, an immunologically distinct group. The population consisted of 158 renal transplants in 146 patients (age range, 1-21 years). PRA was determined with PRA-STAT and microlymphocytotoxicity (CDC), using final cross-match sera. An elevated test was defined as > or =5% reactivity. Statistical analysis for rejection used the chi-square test and for graft survival used the log-rank test. Thirty-five patients (22%) had %PRA-STAT > or =5%, compared with 26 (16%) with %PRA-CDC > or =5%. The percentage with elevated %PRA-STAT was found to correlate with subsequent transplantations (first, 15%; second, 67%; third, 75%). Subsequent analyses utilized only the 136 primary recipients, of whom 20 (15%) had %PRA-STAT > or =5% and 16 (12%) had %PRA-CDC > or =5%. Elevated %PRA-STAT correlated with rejection at 3 months (65% vs. 36%), 12 months (84% vs. 50%), and 24 months (84% vs. 54%) (P<0.05). No association was found between elevated %PRA-CDC and rejection. Patients with %PRA-STAT > or =5% vs. %PRA-STAT <5% had graft survival at 1 year of 89% vs. 84%, at 2 years of 88% vs. 77%, and at 3 years of 61% vs. 72% (not significant). Use of %PRA-STAT > or =5% identifies pediatric recipients who are at increased risk for rejection and may benefit from more potent immunosuppression and/or closer monitoring of graft function.