A study on the association of TNF-α-308, IL-6-174, IL-10-1082 and IL-1RaVNTR gene polymorphisms with rheumatic heart disease in Pakistani patients

Abstract

Inflammation is an important contributor to the pathogenesis of rheumatic heart disease (RHD), a disorder of heart valves caused by a combination of immune, genetic and environmental factors. Cytokines are important mediators of inflammatory and immune responses. The aim of this study was to investigate the role of cytokine gene polymorphisms and their potential usefulness as biomarkers in RHD patients from Pakistan. We screened 150 RHD patients and 204 ethnically matched controls for tumor necrosis factor (TNF)-α-308G/A, interleukin (IL)-10−1082 G/A, interleukin (IL)-6-174 G/C and a variable number of tandem repeats (VNTRs) polymorphism of the IL-1Ra gene using polymerase chain reaction. The results showed that TNF-α-308 A and IL-6-174 G alleles were associated with susceptibility to RHD (p=0.000; OR=2.81; CI=1.5–5.14 and p=0.025; OR=1.50; CI=1.04–2.16 respectively). The TNF-α-308 AA and GA genotypes were associated with susceptibility to RHD (p=0.012; OR=9.94; CI; 1.21–217.3 and p=0.046; OR=1.97; CI=0.98–3.97 respectively) while the GG genotype seemed to confer resistance (p=0.003; OR=0.39; CI=0.20–0.76). The GG genotype for IL-6-174 was significantly associated with predisposition to RHD (p=0.015; OR=2.6; CI=1.17–5.85). The A1 (four repeats) and A2 (two repeats) alleles at the IL-1Ra VNTR polymorphism were associated with resistance and susceptibility to RHD respectively. However, this polymorphism deviated from Hardy–Weinberg equilibrium in both patients and controls in our population. TNF-α-308 and IL-6-174 polymorphisms may be useful markers for the identification of individuals susceptible to RHD in Pakistan. These individuals could be provided aggressive prophylactic intervention to prevent the morbidity and mortality associated with RHD.