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 syn drome. 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 x 103 cpm/culture), for concanavalin A (6.9 versus 28.7 x 103 cpm/culture), and for pokeweed mitogen (7.1 versus 22.4 x 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 x 103 cpm when cultured alone but only 0.9 x 103 cpm when cocul tured 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 x 105 patient lymphocytes added to 1.5 x 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 3and OKT 4positive cells, and the helpensuppressor ratio, but not with the percentage of suppressor cells. These data indicate that sup pressor cell activity can be found in homosexuals with the prodrome of the opportunistic infection, Kaposi's sarcoma syn drome, and may be responsible for their in vivo immune defi ciency. It also suggests that therapeutic maneuvers, which would restore the helpersuppressor ratio towards normal, might benefit the patients clinically.