Suppressor Cell Activity among the Peripheral Blood Leukocytes of Selected Homosexual Subjects

Suppressor cell activity was investigated in the peripheral blood leukocytes of 21 homosexual subjects with a presumed prodrome of the opportunistic infection, Kaposi's sarcoma syndrome. Patient lymphocytes, either untreated or irradiated with 4000 rads, were cultured alone or were cocultured with normal lymphocytes. The cultures were stimulated with phytohemagglutinin, concanavalin A, and pokeweed mitogen. The proliferative responses of these cultures were compared to each other and were related to concurrently studied delayed hypersensitivity skin test responses to dermatophytin, candida varidase, mumps, and purified protein derivative of tuberculoprotein; to the proportion of erythrocyte rosette-forming cells and OKT 3-, OKT 4-, and OKT 8-positive cells; and to the OKT 4: OKT 8 ratio in the peripheral blood leukocytes. Patient blastogenic responses were significantly lower than controls for phytohemagglutinin (29.9 versus 75.3 Х 10³ cpm/culture), for concanavalin A (6.9 versus 28.7 Х 10³ cpm/culture), and for pokeweed mitogen (7.1 versus 22.4 Х 10³ cpm/culture). In 12 of 21 patients, significant suppressor cell activity was detected for all three mitogens. For example, for these 12, the normal controls showed 82.9 Х 10³ cpm when cultured alone but only 0.9 Х 10³ cpm when cocultured with the patient's cells. Irradiation reversed the suppressor cell activity in nine of 12 of the subjects. Suppressor cell activity was seen with as few as 0.125 Х 10⁵ patient lymphocytes added to 1.5 Х 10⁵ normal lymphocytes. The percentage of suppression of the normal blastogenic responses correlated significantly with the patient blastogenic responses, the percentage of erythrocyte rosette-forming cells, the percentage of OKT 3- and OKT 4-positive cells, and the helper: suppressor ratio, but not with the percentage of suppressor cells. These data indicate that suppressor cell activity can be found in homosexuals with the prodrome of the opportunistic infection, Kaposi's sarcoma syndrome, and may be responsible for their in vivo immune deficiency. It also suggests that therapeutic maneuvers, which would restore the helper: suppressor ratio towards normal, might benefit the patients clinically.