Impact of tuberculosis on serum leptin levels in patients with HIV infection

Aim: Tuberculosis (TB) and human immunodeficiency virus (HIV) are classical wasting diseases accompanied by immunosuppression. As leptin is involved in the weight regulation and cellular immunity, we investigated the role of leptin levels in the co-infection of HIV and TB (HIV-TB). Methods: The study group consists of the patients with asymptomatic HIV infection (n = 20), patients with HIV-TB co-infection (n = 20) and healthy control subjects (n = 20). Serum leptin levels and the concentrations of IFN-γ, TNF-α, IL-12 and IL-4 cytokines were measured by ELISA before the start of the treatment. CD4⁺ T-cell counts were determined in patients with HIV and HIV-TB by flow cytometry. Body mass index (BMI) of the study subjects was calculated. Results: Serum leptin levels and BMI were significantly lower in the patients with HIV-TB than control and HIV subjects. Multivariate regression analysis showed that serum leptin concentration was significantly dependent on BMI and sex but not on age and the disease groups. The leptin levels did not correlate either with CD4⁺ T-cell counts or with any of the serum cytokines in HIV and HIV-TB patients. Conclusion: Thus our finding suggests that the leptin concentrations were strongly associated with BMI and gender but not with the disease state or with the circulating cytokine levels