Inhibition of NK cell-induced cytolysis by thiocarbamide antithyroid drugs.

The thiocarbamide antithyroid drugs, methimazole and propylthiouracil, suppressed natural killer (NK) cell-induced cytolysis in vitro (determined by the release of 51Cr-chromate from labelled target cells) in a dose-dependent manner. Parallel experiments demonstrated a similar reduction in NK cell luminol chemiluminescence during activation by K562 tumour cells. It would appear, therefore, that an association may exist between NK cell-induced cytolysis and the peroxidase/oxygenase activity of these lymphocytes.