Inhibitory effect on monocyte-mediated cytotoxicity of sera from patients with multiple myeloma and malignant lymphoma.

There was no difference in monocyte-mediated cytotoxicity between monocytes from patients with multiple myeloma or malignant lymphomas and monocytes from control persons after in vitro culture for 5 d. Cytostatic and cytolytic ability of lymphokine-activated monocytes cultured in medium with patient serum was significantly depressed compared to the ability of monocytes cultured with normal serum. A similar depression of cytostasis was found with non-activated monocytes of both patient and control origin. Sera from myeloma and lymphoma patients impaired the monocyte-mediated cytotoxicity equally.