Innate Immunity to Tuberculosis in advanced HIV/AIDS patients
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Date
2012-07
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Addis Ababa University
Abstract
Several factors influence resistance or susceptibility to tuberculosis (TB) in an immunocompromised host. Animal studies have shown the contributions innate immunity on host resistance to TB disease in the absence of intact adaptive immunity (Feng et al., 2006). We extended these observations to humans to assess the innate mechanisms that prevent the development of active TB in advanced AIDS patients with compromised CD4+ T cell functions. In a cross-sectional study, we determined macrophage mediated killing of Mycobacterium tuberculosis (M. tuberculosis ) and measured the production of inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10). We also assessed intracellular expression of IFN-γ in NK, γ/δ (CD3+ γ/δ+) and adaptive (CD3+ γ/δ -) cells in response to purified protein derivative (PPD) and live M. tuberculosis . We found better innate functions in macrophage killing and IFN-γ production in AIDS patients with latent TB infection compared to AIDS patients who progress to TB disease, but the differences did not reach statistical significance. The study suggests that variation in susceptibility to TB in AIDS patients could be due to innate immunity but our observation warrants confirmation in larger prospective study to consolidate this hypothesis. A better understanding of these factors might help in making preventive therapies to HIV patients that are most likely to develop TB.
Keywords: Innate immunity, Susceptibility, Resistance, Latent TB infection
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Keywords
Innate immunity, Susceptibility, Resistance, Latent TB infection