MACROPHAGES FROM HUMAN IMMUNODEFICIENCY VIRUS-POSITIVE PERSONS ARE DEFECTIVE IN HOST-DEFENSE AGAINST HISTOPLASMA-CAPSULATUM

The phagocytic and fungistatic activity of monocyte-derived macrophage s from human immunodeficiency virus (HIV)-positive persons against His toplasma capsulatum yeasts was determined, Macrophages from HIV-positi ve patients were profoundly deficient in their capacity to recognize a nd bind H. capsulatum, but ingestion of bound yeasts was normal. The b inding of H. capsulatum by patient macrophages tended to decrease with a decrease in CD4(+) T lymphocyte counts. Another major defect was th at patient macrophages were more permissive for the intracellular grow th of H. capsulatum. Macrophages from 22 of 58 patients showed a great er than or equal to 2-fold increase in intracellular growth compared w ith control macrophages. Thus, in addition to defects in cell-mediated immunity caused by a loss of CD4(+) T cells, macrophages from HIV-pos itive patients exhibit intrinsic defects in macrophage function agains t H. capsulatum that may contribute to the increased susceptibility of HIV-positive patients to disseminated histoplasmosis.