Quantitative analysis of immunosuppression in cyclosporine-treated heart transplant patients with lymphoma.

Lymphoma remains an important complication after heart transplantation in the era of cyclosporine immunosuppression. It has been generally assumed that the occurrence of lymphoma related to quantitative degree of immunosuppression, and this assumption is exemplified in the treatment of some such lymphomas with reduction of immunosuppression. Seventy-five consecutive survivors of heart and heart-lung transplantation between December 1980 and July 1983 were treated with cyclosporine and steroids; some received rabbit anti-thymocyte globulin for prophylaxis or treatment of rejection. Measured quantitative parameters of immunosuppression during the first three months after transplantation included mean cyclosporine level, total rabbit anti-thymocyte globulin dosage, number of days of T-cell suppression, and mean cyclosporine level during T-cell suppression. Serial Epstein-Barr virus antibody titers were measured. Lymphoma was diagnosed in six patients. The mean number of episodes of rejection did not differ between the lymphoma and the non-lymphoma groups. All quantitative measures of immunosuppression were higher in the lymphoma group, but this difference achieved statistical significance only in the case of total dosage of rabbit anti-thymocyte globulin (p less than 0.02). Four of the six lymphoma patients received some or all of their rabbit anti-thymocyte globulin dosage as prophylaxis against rejection; one received rabbit anti-thymocyte globulin solely for rejection; and the sixth received no rabbit anti-thymocyte globulin. Ebstein-Barr virus titer conversion (four-fold rise in titer) alone was not significantly associated with occurrence of lymphoma. However, logistic regression analysis suggested that Epstein-Barr virus conversion in concurrence with high mean cyclosporine levels predicted a higher risk of lymphoma.(ABSTRACT TRUNCATED AT 250 WORDS)