Eleven of 15 patients with a first acute rejection episode following cadaveric renal transplantation resumed adequate graft function and increased peripheral blood suppressor T-lymphocyte activity following treatment with 'pulse' methylprednisolone and aminophylline (1000mg orally daily for 14 days). Four of 11 patients treated with 'pulse' methylprednisolone alone resumed adequate graft function, but only two of these had elevated peripheral blood suppressor T-lymphocyte function. Nine of the 11 responding patients exhibited plasma suppressor activity to xenogenic graft versus host reaction but such activity was not observed in the plasma of any of the 11 patients who received methylprednisolone alone.