Lymphocyte subpopulation monitoring in cyclosporine-treated patients following heart transplantation.

Circulating lymphocyte subpopulations were studied in 18 consecutive patients treated with cyclosporine-prednisone immunosuppression during the first month following heart transplantation. Eleven patients showed no evidence of graft rejection. There were eight episodes of acute rejection demonstrated at endomyocardial biopsy in 7 patients. Three patients were treated with corticosteroids, 3 were treated with rabbit antithymocyte globulin (RATG), and 1 died before treatment (early mortality: 5.6%). Using the monoclonal antibody technique, 150 determinations of lymphocyte subpopulations were performed and were correlated with 72 endomyocardial biopsy specimens. Cyclosporine immunosuppression caused a significant (p less than 0.05) decrease in total lymphocyte count (38%) and in the number of OKT3 (52%) and OKT4 cells (55%). During acute rejection, total lymphocytes and OKT3, OKT4, and OKT8 cells all increased significantly, but the T4 to T8 ratio did not change significantly. Treatment of rejection with corticosteroids resulted in a moderate but not significant decrease in all T-cell types, whereas RATG caused a marked but not selective decrease in all T-cell groups. In conclusion, T cells decrease with cyclosporine immunosuppression and with treatment of rejection and increase at onset of rejection, but the T4 to T8 ratio has no predictive value for the diagnosis and severity of rejection, and the sensitivity of the method does not permit its use to assess the degree of immunosuppression with cyclosporine following heart transplantation.