Alterations in T and B lymphocytes in heart transplant patients early and late postoperatively.

Alterations in the percent and absolute number of thymus-derived (T) and bursa-equivalent (B) lymphocytes in peripheral blood were followed in 10 patients treated with antithymocyte globulin, prednisone, and azathioprine after cardiac transplantation. During the 1st postoperative wk the percent of T cells dropped below 10% in almost all cases (normal range, 65-91%) with a concomitant rise in the percent of B cells. However, the absolute T- and B-cell counts were both markedly depressed (less than 200 cells/mm3). During the 7-wk postoperative period the percent of T cells rose to 45-60% and the absolute count rose from 100 to 350 cells/mm3 (normal range, 1,092-2,400 cells/mm3). Although the percent of B cells was elevated (35-50%) during this period, the absolute B-cell count remained below the range of normals (268-640 cells/mm3). Follow-up of long-term survivors (3-60 mo postoperative) showed a continued marked T (467 cells/mm3) and B (95 cells/mm3) lymphocytopenia. Chronological relationships between the percent and absolute T-cell count and episodes of graft rejection in individual patients are discussed as possible adjuncts in the prediction of rejection crises.