Development of malignant tumor in renal transplant recipients and their NK and LAK activity

Abstract

We surveyed development of cancer in Japanese renal transplant recipients by collecting questionaires from the institutions performing renal transplantation in Japan. A total of fifty-five malignant diseases occurring in renal transplant recipients was reported.
In order to study the effect of immunosuppressive drugs (Pred, AZ, CYA) on the development of malignant diseases in renal transplant recipients, NK and LAK activities of peripheral blood lymphocytes of twenty-one renal transplant recipients receiving those drugs for more than three years were investigated. The NK and LAK activities of renal transplant recipients were significantly lower than those of healthy volunteers or patients suffering from gastric cancer (p<0.01). Both NK and LAK activities of patients receiving Az were significantly lower than those of patients not receiving it. Pred has tendency to suppress NK and LAK activities of renal transplant recipients in dose dependent manner. However, both NK and LAK activities of patients receiving CYA were significantly higher than those of patients not receiving it (p<0.01). Our findings indicate that CYA has less inhibitory effect on NK and LAK activities of renal transplant recipients than conventional drugs (Pred, or Az). It seems that CYA has significant immunosuppressive effect on renal transplant recipients, but it does not impair the host defense mechanism of those patients as much as conventional drugs.