Cryptococcal antigenemia among HIV seropositive patients accessing care in antiretroviral therapy (ART) clinics in Calabar, South Southern Nigeria

Abstract

Background: Cryptococcus neoformans infection is a life threatening disease especially when associated with immunosupression like HIV/AIDS. The greatest burden of disease occurs in sub-Saharan Africa, where mortality is estimated to be 17%. The finding of cryptococcal antigen in the blood represents a condition of systemic invasion with the fungus. Clinical manifestation of infection with Cryptococcus neoformans in AIDS patients is generally more evident at CD4 cells ≤100 cells/µl. This study was carried out to determine cryptococcal antigenemia among HIV seropositive patients accessing care in ART clinics as patients are not screened routinely despite reports of relatively high co-infection rates with HIV. Methods: This prospective cross-sectional study was carried out on ART-treated and ART-naive HIV positive adult patients attending ART clinics in two tertiary hospitals in Calabar, Nigeria. The sero-prevalence of cryptococcal antigen among the patients was determined using the cryptococcal antigen latex agglutination system (CALAS) (Wampole Laboratories, USA), according to the manufacturer’s instruction. The CD4 count levels of each patient were determined by flow cytometry using the fluorescent activated cell sorter BD FACS Count system (Becton Dickinson). Results: Out of the 272 HIV positive subjects enrolled in the study, 116(42.6%) were ARV-naive and 156(57.4%) were ARV-treated patients. A 5.1% cryptococcal antigenemia prevalence was established in the study. Infection rates were higher among subjects receiving ART 11/156 (7.1%) than in ART-naive subjects 3/116 (2.6%). Infection rates 5(35.7%) peaked at age 25-34 years. The mean CD4 counts of subjects with cryptococcal infection were 100.7±67.8 cells/µl, with a minimum CD4 count of 13.0. All the infections occurred among subjects with CD4 counts ≤200 cells/µl of blood. There was a statistically significant effect of cryptococcal antigenemia on the CD4 counts of the subjects (t=3.7, p=0.002). Conclusion: This study reveals that cryptococcal antigenemia is a health problem among HIV/AIDS patients in our locality. Cryptococcal antigenaemia seem to be more common among HIV patients on ART. The CD4 count levels among the ART treated subjects could have been boosted by administration of ART