A prospective randomized study evaluating the effectiveness of antithymocyte globulin (ATG) for reversal of established rejection was undertaken in 20 recipients of related donor renal allografts. The patients were initially treated with azathioprine and prednisone. With the onset of acute rejection they were randomly assigned to additional treatment with either ATG or high-dose steroids. Eight of 10 patients treated with ATG had prompt reversal of acute rejection and have had no further evidence of rejection. Two of the patients had continuing evidence of rejection after several days of ATG treatment and therefore received high-dose steroids as well. One patient regained normal function but the second suffered repeated rejection episodes which eventually resulted in allograft failure.
All 10 patients treated with high-dose steroids had initial reversal of rejection, although four required irradiation of the graft and actinomycin therapy as well and five patients subsequently required treatment for second and third rejection episodes. One patient in this group died with perforated divertic-ulitis following reversal of rejection.
With a mean followup of 14 months, 9 of 10 patients treated with ATG have functional allografts, renal function being normal in 8 patients. Nine of 10 patients treated with steroids have functional grafts but renal function remains impaired in three. The effectiveness of ATG when added at the time of acute allograft rejection has been demonstrated. The major advantage of ATG for rejection reversal has been a marked decrease in the cumulative steroid dose administered to these patients. This may avoid many long-term adverse effects of steroids such as the fatal diverticulitis complication observed in this study. An additional suggested benefit is a decreased incidence of second rejection episodes in the ATG-treated patients.