Role of western blot assay for the diagnosis of histoplasmosis in AIDS patients from a National Institute of Infectious Diseases in Rio de Janeiro, Brazil

Abstract

Background: Histoplasmosis is a frequent fungal infection in HIV/AIDS patients, with high morbimortality rates when diagnosis and treatment are delayed. Antibody detection, which is faster than the gold standard culture test, hastens the laboratory investigation.

Objectives: To evaluate the role of WB for antibody detection in the diagnosis of histoplasmosis among HIV/AIDS patients.

Patients and methods: Fifty patients with proven or probable histoplasmosis were included. Clinical, epidemiological and laboratory data were described in the same population after a review of their medical records. WB was performed using deglycosylated histoplasmin.

Results: About 82% of patients were adult males and the mean age was 39.3 years. CD4⁺ T lymphocyte count less than 150 cells/mm³ was observed in 62% patients. Antibodies against Histoplasma capsulatum M antigen were detected in 62% of patients, and against both M and H antigens in 28% of individuals. Sera from 10% of patients were nonreactive. Histoplasmosis was the first opportunistic infection in 38% of the cases. Disseminated and pulmonary histoplasmosis occurred in 84% and 16% of patients, respectively. The overall mortality was 16%.

Conclusion: WB could be useful for the histoplasmosis diagnosis in HIV/AIDS patients because of its easefulness and good sensitivity in a population where antibody production is hampered.

Keywords: HIV/AIDS patients; antibody detection; histoplasmosis; immunodiagnosis; western blot.