Caspase 1 and caspase 8 in HIV infected patients with and without tuberculosis

Background: Caspase 8 is involved in apoptosis mediated by Fas and p55 tumor necrosis factor receptor ligation in HIV infection. Apoptosis is partially mediated by interleukin-1 beta-converting enzyme (caspase-1). Aims: We determined apoptosis, using caspase-1 and caspase-8, among patients with HIV infection, with and without tuberculosis (TB), those with TB alone and healthy individuals. Setting and design: Cross-sectional analysis of caspase-1 and caspase-8 among patients with HIV infection, with and without TB, those with TB alone and healthy individuals. Materials and Methods: Nineteen HIV infected patients with TB (HIV+/TB+) and 20 with HIV infection without TB (HIV+/TB-) were studied. Fifteen individuals with TB alone were disease controls (HIV-/TB+) and 20 were healthy controls (HIV-/TB-). Caspases were measured by single-step ELISA using commercially available monoclonal antibodies. Statistical Analysis: Two-way ANOVA and Pearson's correlation coefficient. Results: Mean CD4 counts of HIV+/TB+ were lower than HIV+/TB- (p<0.05). OD value of caspase 1 in HIV+/TB+ was 0.295±0.05, while that in HIV+/TB- it was 0.302±0.18. It was 0.293± 0.07 in HIV-/TB+ and in HIV-/TB- the values were 0.287±0.06. OD value of caspase 8 in HIV+TB+ was 0.307± 0.07, lower than HIV+/TB- (0.927±0.25). It was 0.008±0.03 in HIV-/TB+ and in HIV-/TB-, 0.074±0.004. Values of caspase 8 in patients with HIV infection (with/without TB) were higher than those with TB alone or healthy individuals (p<0.01). Levels of caspase 8 in HIV+/TB- were higher than patients with HIV+/TB+ (p<0.01). Conclusion: Levels of caspase-1 are not different irrespective of presence or otherwise of TB and HIV infection. Fas-related apoptosis is higher in HIV infection. With concomitant TB, levels of caspase 8 were lower as compared with those without TB.