Comparison of Minnesota antilymphoblast globulin and Upjohn antithymocyte globulin for induction immunosuppression of human renal allografts.

BACKGROUND: An analysis of heterologous polyclonal antisera in first renal transplants was continued after replacement of Minnesota antilymphoblast globulin (MALG) with antithymocyte globulin (ATGAM), testing the hypothesis that these are functionally equivalent drugs. METHODS: Sequential induction immunosuppression used MALG (20 mg/kg/day, n = 33) or ATGAM (15 mg/kg/day, n = 14), corticosteroids, azathioprine and cyclosporine. White blood cell, platelet, and T-cell subsets were measured. Percent of patients with and time to first rejection were determined. Anti-horse antibody was measured by enzyme-linked immunosorbent assay. Minimum follow-up after transplantation was 1 year. RESULTS: Human leukocyte antigen mismatch, peak and current panel reactive antibodies, age, gender, percent cadaver donors and diabetic recipients were similar. Depletion of CD2, CD3, CD4, and CD8 T-cell subsets and platelet and white blood cells was similar. Early renal function was better with MALG than with ATGAM (p = 0.005, ANOVA), but by 2 weeks the groups were similar. The percent of patients receiving MALG versus patients receiving ATGAM with cytomegalovirus (28 versus 50), anti-horse antibodies (50 versus 62), and rejection (58 versus 50) and the median day of first rejection (48 versus 47) were similar. Three grafts were lost. CONCLUSIONS: MALG and ATGAM are equally effective in eliminating T cells and preventing and delaying the onset of renal allograft rejection.