Effects of prophylactic rabbit antithymocyte globulin in cardiac allograft recipients treated with cyclosporine.

The prophylactic use of rabbit antithymocyte globulin (RATG) was evaluated in 13 cardiac allograft recipients who received a low-dose of RATG (175 +/- 32 mg) after transplantation (group 1). The patients were retrospectively compared with 13 parallel cases receiving the same treatment except for the initial RATG (group 2). There were no differences in the patient composition and the level of the basic immunosuppression therapy with cyclosporine. The patients treated with RATG (group 1) showed substantially greater suppression of T helper and total T cells up to 10 and 20 days after surgery, respectively. The incidence of rejection episodes during the initial admission seemed lower in patients receiving RATG, with a borderline significance (1.4 versus 2.4, p = 0.06). This accounts for the reduced requirement of methylprednisolone in treating rejection in patients in group 1 (1.3 gm versus 4.0 gm, p less than 0.02). Moreover, the patients without initial doses of RATG (group 2) more frequently experienced recurrent rejection (five of 12 versus nine of 10, p less than 0.05), which necessitated rescue RATG; the initial difference in the RATG usage disappeared by the time of discharge. Serious infection occurring after antirejection therapy was common in the group 2 patients without initial doses of RATG, although the overall incidence of infection was not statistically different. Prophylactic use of RATG at the dosage used appeared to reduce the incidence of rejection and the requirement for intravenous steroids and other immunosuppressants. It seems warranted to test this approach in a prospective randomized manner.