Antigen-specific immunoglobulins in patients with acute pulmonary, chronic pulmonary, or disseminated histoplasmosis.

Patients infected with Histoplasma capsulatum exhibit protean clinical manifestations and similarly express variable humoral immune responses. Therefore, the specific goals of this study were to more clearly define host immune responses by determining the concentrations of total and H. capsulatum-specific immunoglobulins in sera from patients with acute or chronic pulmonary and disseminated histoplasmosis. H. capsulatum-specific (AS) IgG, IgA and IgM, and total IgE were determined by radioimmunoassays while total IgG, IgA, and IgM were quantitated by laser nephelometry. In general, total IgG and IgA were elevated, while IgM and IgE were either decreased or normal for the three clinical forms of histoplasmosis studies. Antigen-specific IgG and IgA were markedly elevated in all classes of disease, whereas AS-IgM was only slightly increased. Total and AS-IgG were elevated in the sera of chronic patients directly proportional to the number of demonstrable precipitin bands.