Comparison of polyclonal antibody sera for early prophylaxis following cardiac transplantation.

In order to test different polyclonal antibody regimes as early prophylaxis against cardiac rejection, 42 patients (ages 30 to 60 years) transplanted at the University of Michigan from December 1986 to August 1988 were randomized to receive antithymocyte globulin (ATGAM, Upjohn, n = 19) or antilymphoblast globulin (MALG, University of Minnesota, n = 23). Cyclosporine (CYA), steroids, and azathioprine (AZA) administration was similar in all randomized patients during early prophylaxis. CYA was begun preoperatively and maintained at a serum level of 250-300 ng/ml. After an initial steroid taper, patients were maintained on 0.3 mg/kg/day. AZA was begun after polyclonal prophylaxis at 1-2 mg/kg. All patients received either ATGAM or MALG for 7 days or until the serum CYA reached 250 ng/ml. Although sex, pretransplant hemodynamics, follow-up length, total drug dose, mortality (one per group), postoperative white blood cell and lymphocyte counts did not differ between groups, MALG significantly delayed the first rejection episode as compared to ATGAM (35 +/- 4 vs 22 +/- 3 days, P less than 0.05). Additionally, there was decreased rejection during follow-up for the MALG group with 1.5 +/- 0.2 rejections per patient as compared to 2.3 +/- 0.3 with ATGAM. Furthermore, the significant infection rate with MALG was only half that of the ATGAM group (6/23 vs 11/19) (P less than 0.05). The beneficial effect of MALG may be due to immune-specific differences in its polyclonal spectrum.