DECREASED SUPPRESSOR CELL-ACTIVITY IN DISSEMINATED GRANULOMATOUS INFECTIONS

Abstract

The effect of granulomatous infections upon the activity of a T lymphocyte subclass in human peripheral blood that can be induced by concanavalin A (Con A) to function in a suppressor mode was studied. Peripheral blood lymphocytes (PBL) from 11 patients with disseminated mycotic or mycobacterial infection or from normal controls were preincubated with and without Con A, washed and cultured with allogeneic PBL freshly drawn from healthy donors sensitive to histoplasmin. DNA synthesis was then measured in co-cultures stimulated by Con A, histoplasmin or by the mixed lymphocyte culture (MLC) reaction alone. As compared with cells precincubated without Con A, the Con A-pretreated cells from 10 of 11 normal donors clearly suppressed the response to Con A by normal allogeneic PBL. The response of normal PBL was augmented in 6 of 11 co-cultures, to which Con A-pretreated cells from patients were added (P < 0.01). The patients'' pretreated cells were significantly less effective in suppressing the responses of normal PBL to histoplasmin (P < 0.01), and in a 1-way MLC reaction (P < 0.05). The Con A-induced suppressor activity of PBL from 9 patients with localized granulomatous infections did not differ significantly from that exerted by PBL of normal controls in 2 of the 3 co-culture systems employed. Either dysfunction or a reduction of the Con A-inducible T-suppressor cell subpopulation in peripheral blood is frequent among patients with disseminated granulomatous infections.