Cytokine-activated human monocytes show differential cytotoxicity toward fresh and cultured Kaposi's sarcoma cells.

We have examined the ability of peripheral blood monocytes (PBMs) isolated from AIDS-related Kaposi's sarcoma (KS) patients or normal donors to kill (a) autologous KS tumor cells from skin biopsies of AIDS patients, (b) a tumorigenic cell line derived from a histologically verified AIDS-KS skin tumor, and (c) the WEHI-164 fibrosarcoma line. Unstimulated PBMs, and PBMs activated by IFNs, IL-2, or TNF-alpha, were tested for their ability to lyse 51Cr-labeled tumor targets. PBMs from both normal and KS patients, when activated by cytokines, showed enhanced cytolysis of both WEHI-164 and the KS cell line. PBMs from two of three AIDS patients lysed their autologous fresh KS tumor cells. These results indicate that PBMs from AIDS-KS patients can be induced by cytokines to elicit potent antitumor activity, including cytolysis of autologous KS tumor cells.