Humoral response to disseminated infection by Mycobacterium avium-Mycobacterium intracellulare in acquired immunodeficiency syndrome and hairy cell leukemia.

Antibody to Mycobacterium avium-Mycobacterium intracellulare antigen was measured by immunodiffusion, enzyme-linked immunosorbent assay (ELISA), and indirect immunofluorescence in sera from 30 patients with acquired immunodeficiency syndrome (AIDS), 10 patients with hairy cell leukemia, and 33 hospitalized and healthy controls. Ten patients with AIDS and three patients with hairy cell leukemia in the study population had disseminated M. avium-M. intracellulare infection. Patients with AIDS and disseminated infection had antimycobacterial antibody levels, demonstrated by ELISA, that did not differ significantly from those in uninfected patients with AIDS or controls. Infected patients with hairy cell leukemia had significantly higher levels of antimycobacterial antibody, demonstrated by ELISA, than did uninfected patients with hairy cell leukemia or controls (P less than .001). One patient with hairy cell leukemia, studied serially, showed a greater than 100-fold rise in antibody titer with the onset of infection. These results further demonstrate that AIDS involves a functional defect in humoral immunity, in addition to impairment of cellular immune function.