Patterns of Immune Response in Chronic Pulmonary Histoplasmosis

Abstract

Humoral and cellular immunity were evaluated in patients with chronic pulmonary histoplasmosis. Results of histoplasmin skin tests and in-vitro histoplasmin-induced lymphocyte transformation agreed in the great majority of individuals. As a group, patients with chronic pulmonary histoplasmosis exhibited histoplasmin-induced lymphocyte transformation that was no different from normal subjects with positive skin tests. However, a wide spread of transformation values was observed, from reactivity greater than that in skin-test positive, normal subjects to absence of transformation. Six of 10 patients with active disease were found to have histoplasmin-induced transformation greater than the mean of normal subjects with positive skin tests. Two patients with active disease had negative skin tests and depressed in-vitro lymphocyte responsiveness not only to histoplasmin but also to candida extract and phytohemagglutinin. A consistent correlation between titers of CF or precipitin antibody in autologous serum and histoplasmin-induced transformation values could not be demonstrated. Impaired responsiveness of lymphocytes to histoplasmin was a temporary phenomenon in one patient whose transformation was retested over a period of a year.