The correlation of tuberculosis smear results and immuno-suppression with CD4+ counts as a surrogate marker among HIV infected patients.

Background: Human immunodeficiency virus (HIV) and M.tuberculosis are two intracellular pathogens that interact at the cellular, clinical and population levels. Since the recognition of AIDS in 1981, the number of reported cases of TB in the has increased substantially, especially in regions with high incidence of AIDS. The main aim of this study was to establish weather there is a relationship between sputum smear positives and low CD4 cell counts among HIV infected patients.Materials and methods: This was a retrospective study involving 473 participants. The patients recruited in this study were those who tested HIV positive and smear positive for TB. Their HIV status was determined by performing an HIV blood test, if they were HIV positive their CD4 cell count were then made.Results: This study examined the relation between smear positivity and low CD4 (below 200cells/µl) together with CD8 and CD3 markers as a measure of immune function among patients infected with HIV. The study participants’ constituted males 67% and females 33%. The overall mean age was 33.2 (SD 6.9) with the youngest and oldest participants being 18 and 60 respectively. It was found that smear positive results negatively (r=-0.13; p=0.021) correlated with CD4+ below 200 cells/µl. No correlation was observed between smear positives and CD8+ or CD3+ since the calculated correlation coefficient was not significant 0.007 (p=0.9) and 0.03 (p=0.6) respectively. There are more 3+ smear results below 200 cells/µl than the others while above 200 cells/µl 1+ was the most commonly reported smear result. The scanty smear positives were the least commonly reported result in the low and high CD4 counts. Conclusion: The smear positive result negatively correlated with a low CD4+ (r=-0.13; p=0.021) but no correlation with low CD+8 and CD+3 results was observed. The long held theory that low bacillary counts in patients with low CD4+ counts needs to be revisited. The reduction of CD4+ cell count parallels' that of the total lymphocyte count and is more marked in patients with high bacillary counts. Further, studies are required to confirm these findings