In vitro suppression of myelopoiesis by adherent murine splenocytes in experimental disseminated histoplasmosis.

Supernatant culture media obtained from adherent spleen cell preparations of mice experimentally infected with Histoplasma capsulatum yeast cells suppressed in vitro growth of human myeloid cells. This suppression was significantly greater than that obtained when splenocytes from normal mice or those inoculated with killed yeast cells were used. The use of indomethacin partially blocked this suppressive effect. A direct relationship was observed between the levels of prostaglandin E (PGE) per 10(6) adherent cells in the splenocyte preparations and the degree of in vitro myelosuppression. These findings suggest a possible mechanism for the leukopenia frequently observed in disseminated histoplasmosis.