Delayed-type hypersensitivity, in vitro T-cell responsiveness and risk of active coccidioidomycosis among HIV-infected patients living in the coccidioidal endemic area.
The prognostic importance of specific and general tests of immune function were examined among a cohort of 170 subjects infected with human immunodeficiency virus type-1 (HIV), living in an area endemic for the fungal infection coccidioidomycosis. Using the proportional hazards model and multivariate analysis, lack of expression of coccidioidal delayed-type hypersensitivity (DTH) was found to be dependent on anergy in response to the non-coccidioidal antigens mumps, Trichophyton and Candida (relative hazard 4.2, 95% CI 1.8-9.8, P=0.001). Among subjects with CD4 lymphocyte counts >/=250 microl-1 on entry into the study, the in vitro lymphocyte transformation (LT) response to the coccidioidal antigen toluene spherule lysate was 4967+/-1652 (mean counts per minute (c.p.m.)+/-SEM) in subjects with coccidioidal DTH compared with 136+/-222 in those with negative DTH (P<0.001). However, amongst those whose CD4 count was <250 microl-1, LT responses were low and there was no significant difference based on coccidioidal DTH (P=0.965). Using the proportional hazards model and multivariate analysis, only a CD4 count <250 microl-1 was prognostically associated with the development of either active coccidioidomycosis or AIDS. These data indicate that immunodeficiency, particularly a CD4 lymphocyte count <250 microl-1, is the most important factor in the lack of expression of specific immunity to coccidioidomycosis and in the development of active coccidioidomycosis among HIV-infected individuals living in the coccidioidal endemic area.
Medical and Research Services of the Tucson Veterans Affairs Medical Center, Department of Medicine of the University of Arizona College of Medicine 85723, USA. nampel@u.arizona.edu
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D001130:Arizona / Q000453:epidemiology; D018791:CD4 Lymphocyte Count; D003045:Coccidioides / Q000276:immunology; D003047:Coccidioidomycosis / Q000150:complications / Q000453:epidemiology / Q000276:immunology*; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D005500:Follow-Up Studies; D015658:HIV Infections / Q000150:complications* / Q000276:immunology; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D008213:Lymphocyte Activation; D012307:Risk Factors; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*