Interleukin-12B & interleukin-10 gene polymorphisms in pulmonary tuberculosis.

BACKGROUND & OBJECTIVE: Cytokines play an important role in anti-tuberculosis immune response. Skewing of immunity from protective to pathogenic may involve a shift in Th1-Th2 paradigm. Cytokine gene polymorphism is known to be associated with functional differences in cytokine regulation and altered clinical performance in a variety of diseases. The aim of this study was to know whether Interleukin-12B 3' UTR (Taq1) (A/C) and Interleukin-10 (-1082 G/A) gene polymorphisms were associated with susceptibility to pulmonary tuberculosis. METHODS: IL -10 (-1,082 G/A) and IL-12B gene polymorphisms were studied in 132 pulmonary TB (PTB) patients and 143 normal healthy subjects (NHS), using DNA based polymerase chain reaction (PCR) with sequence specific primers and restriction digestion. RESULTS: The allelic as well as genotypic frequencies of Interleukin -10 (-1082) and Interleukin -12B (3'UTR Taq 1) did not differ significantly between the patients and controls. INTERPRETATION & CONCLUSION: Our findings suggested that IL -10 (-1082 G/A) and IL -12B 3'UTR (Taq I) (A/C) gene polymorphisms were not associated either with susceptibility or resistance to pulmonary tuberculosis in the south Indian population.

Interferon gamma (IFNgamma) & interleukin-4 (IL-4) gene variants & cytokine levels in pulmonary tuberculosis.

BACKGROUND & OBJECTIVES: Cytokine gene polymorphisms may alter Th1/Th2 balance with major implications in tuberculosis. The aim of our study was to find out whether Interferon gamma +874A and IL-4 -590T polymorphisms were associated with susceptibility to pulmonary tuberculosis as well as the level of IFNgamma and IL-4 in south Indian population. METHODS: Interferon gamma +874A and IL-4 -590T promoter polymorphisms were studied in 129 pulmonary tuberculosis (PTB) patients and 127 normal healthy subjects (NHS) and were associated with culture filtrate and live Mycobacterium tuberculosis induced IFNgamma and IL-4 production in peripheral blood mononuclear cells (PBMCs). IL-4 gene variants were also associated with IgG antibody levels against M. tuberculosis culture filtrate antigen. RESULTS: The variant IFNgamma genotypes and IFNgamma levels between genotypes did not differ significantly in patients and controls. Significantly increased frequency of variant IL-4 'CT' genotype in PTB patients (P<0.05) and 'CC' genotype in control group (P<0.01) was observed. IL-4 levels were detectable in very few subjects and the IgG levels did not differ between the three IL-4 genotypes. INTERPRETATION & CONCLUSION: The study suggests a lack of functional association of Interferon gamma +874A polymorphism in tuberculosis in south Indian population. The higher frequency of IL-4 'CT' genotype in PTB suggests a possible association of IL-4 -590T promoter polymorphism with susceptibility to tuberculosis, and the 'CC' genotype may be associated with protection.