Antibody response to horse gamma-globulin in recipients of renal allografts: relationship with transplant crises and transplant survival.

Anti-antilymphocyte globulin (ALG) antibody response was measured every day during and after ALG treatment in 52 recipients of renal allografts. IgM antibodies became detectable in 37 patients, usually at day 8 and IgG antibodies appeared 3 days after the IgM in 21 of 37 cases. Of 30 transplant crises recorded between days 6 and 11, 20 coincided with the onset of the antibody response, and the incidence of crises during this period was higher among antibody producers than among nonproducers. In 31 patients a partial or total unresponsiveness to ALG could be achieved. Transplant survival at 3 months was better in this group than among good responders (P less than 0.01). Anti-ALG antibody response may then be usable as an early indication of individual differences in reactivity against transplant antigens.