Microbiological study of tb/hiv co-infection in relation to cd4 count.

Abstract

Individuals with HIV infection are at increased risk for tuberculosis (TB). The altered CD4 T-cell homeostasis induced by HIV infection may play a key role in the development of tuberculosis in HIV-infected patients. Among total 961 subjects with HIV infection studied, 308 (32.055) were found positive for TB. Out of this 244 (25.39%) were positive for pulmonary TB (HIV+TB+) while extra –pulmonary TB was found in 64 (6.66%)HIV patients. The mean CD4 count for extra-pulmonary TB was found to be 104.89 +47.09 cells/μL, the mean CD4 count for pulmonary TB was 198.52+32.25 cells/μL ,while the cumulative TB mean CD4 count was found to be 151.71 + 72.62 cells/μL. In this retrospective analysis, lymphocyte profiles (CD4 counts) of subjects infected with HIV, with or without TB, were evaluated. A statistically significant difference (p = 0.01) was found in the median CD4+ counts between the HIV+TB- (269.80 cells/μL) and HIV+TB+ (151.71 cells/μL ) groups. The results of this study proved that, the lower the CD4 count range, the higher was the risk of developing pulmonary TB and higher was the incidence, but when CD4 count fell below 200 cells/μL, even the risk of developing extra-pulmonary TB was noted . This was proved by finding of 40.25 % of total TB cases were with <100 CD4 count profile, followed by 31.81% of cases were with CD4 count <200 in the present study. Other 300 subjects with RTI but without HIV so immunocompetent subject with normal CD4 count profile were also screened for TB, and only 29 patients (09.67%) were found with open pulmonary TB, when this was compared with HIV positive patients the probability was found to be less than 0.02, which again proves itself that with lowering of CD4 count profile in HIV infected patients the risk of developing TB increases which was directly reflected in increased incidence.