PRETRANSPLANT REJECTION RISK ASSESSMENT THROUGH ENZYME-LINKED-IMMUNOSORBENT-ASSAY ANALYSIS OF ANTI-HLA CLASS-I ANTIBODIES

Soluble HLA enzyme-linked immunosorbent assays (ELISAs) for the detect ion of anti-HLA class I immunoglobulin G (IgG), IgG1, IgG2, IgG3, IgG4 , IgM, and IgA antibodies were developed and used to analyze retrospec tively the correlation between pretransplant allosensitization and pos ttransplant rejection episodes in renal allograft recipients, Enzyme-l inked immunosorbent assay plates were coated with 46 different soluble HLA preparations representing 40 different HLA class I antigens, Afte r incubation with a serum specimen, bound antibodies were detected wit h a peroxidase-conjugated antibody. Serum specimens from 85 patients w ere analyzed, All patients tested positive by microlymphocytotoxicity (ie, >5% panel-reactive antibody [PRA]), Approximately half (56%) of t he patients had experienced one or more rejection episodes within 12 m onths posttransplantation. Fifty-five patients tested positive by ELIS A (total IgG %PRA >10%). A strong correlation between first-year rejec tion and ELISA-detected anti-HLA class I IgG1 was observed (P = 0.0004 ), The predictive value for IgG1 and first-year rejection was 77.5%, d emonstrating that ELISA results identify patients at high risk of reje cting the transplanted kidney. Anti-HLA class I total IgG detected by ELISA also correlated with first-year rejection episodes (P = 0.04). T he presence of anti-HLA class I IgG2, IgG3, IgG4, or IgM was not predi ctive of first-year rejection episodes. Anticlass I IgA antibodies wer e only found in combination with anti-class I IgG1 antibodies. (C) 199 6 by the National Kidney Foundation, Inc.