Cytokine gene polymorphisms and cytokine levels in pulmonary tuberculosis

• Published in: Cytokine (Philadelphia, Pa.) Pa.), 2008-07, Vol.43 (1), p.26-33
• Main Authors: Selvaraj, P., Alagarasu, K., Harishankar, M., Vidyarani, M., Nisha Rajeswari, D., Narayanan, P.R.
• Format: Article
• Language: English
• Subjects: Adult; Cells, Cultured; Cytokines; Cytokines - biosynthesis; Cytokines - genetics; Cytokines - metabolism; Female; Gene polymorphisms; Genetic Predisposition to Disease; Humans; Male; Mycobacterium; Point Mutation; Polymorphism, Genetic; Tuberculosis; Tuberculosis, Pulmonary - genetics; Tuberculosis, Pulmonary - metabolism
• ISSN: 1043-4666; 1096-0023
• DOI: 10.1016/j.cyto.2008.04.011

Polymorphisms in the cytokine genes are known to influence cytokine levels and may be associated with outcome of infections. We investigated the polymorphisms in the cytokine genes namely IFN-γ (+874 and +5644), IL-2 (−330 and +160), IL-4 (VNTR), IL-6 (−174), IL-10 (−1082 and −819) and IL-12B (+1188) in 188 normal healthy subjects (NHS) and 166 pulmonary tuberculosis patients (PTB) using polymerase chain reaction-based methods. To study the influence of cytokine gene polymorphisms on cytokine levels, phytohaemagglutinin and culture filtrate antigen of Mycobacterium tuberculosis-induced cytokine levels were measured by ELISA from 72-h-old peripheral blood mononuclear cell culture supernatants. Significantly decreased frequency of TT genotype of IL-2 −330 polymorphism ( p = 0.024, odds ratio (OR) 0.53, 95% CI 0.31–0.92) was observed in patients compared to NHS. The genotype frequencies of other polymorphisms were not different between patients and NHS. IL-12p40 levels were significantly decreased among NHS with AA genotype of IL-12B gene polymorphism compared to NHS with AC genotype ( p < 0.05). Increased levels of IL-12p40 were observed among patients with CC genotype of IL-12B gene compared to patients with other genotypes ( p < 0.01). The present study suggests that the TT genotype of IL-2 −330 polymorphism may be associated with the protection to PTB in south India. Further, +1188 polymorphism of IL-12B gene either alone or in combination with closely linked genes may regulate IL-12p40 production and may play a major role on acquired immunity to tuberculosis.