Association of <em>IL4RA</em> and <em>IL-8</em> polymorphism in predicting susceptibility towards tuberculosis

Abstract

Mycobacterium tuberculosis is an infectious bacterial disease frequently affecting the lungs. With two fatalities from tuberculosis (TB) occurring every three minutes, India has the highest disease burden. The aetiology of tuberculosis has been linked to IL-8 and IL-4RA. Thus, the impact of the IL4RAQ576R and IL8 gene polymorphism on TB susceptibility was assessed. 301 healthy and 301 TB patients participated in a cross-sectional study. PCR RFLP was performed to identify the genotype of the IL4RAQ576R and IL-8 +781C/T gene polymorphism. The odds ratio and 95% confidence intervals were calculated using logistic regression to evaluate the risk of TB with IL4RAQ576R and IL-8 +781C/T polymorphism. A significant association was found between IL-4RA (p=0.04) and IL-8 +781 C/T (p= 0.03) in tuberculosis. Further, when clinical symptoms were compared with both polymorphisms, two of them, i.e., cough in IL-4RA576R (p=0.04) and breathlessness (p=0.01) in IL-8 +781C/T, showed a significant association. Moreover, different combinations of the SNPS were made, and the 3 risk allele shows a significant protective role (p=0.02). There is considerable evidence which shows that M. tuberculosis causes TB, an infectious disease that is genetically predisposed. The results of our study also showed that IL-4 RA Q576R and IL-8 +781 C/T played a significant protective function against tuberculosis, confirming the claim mentioned earlier. However, only the cough in IL-4RA576R and the dyspnea in IL-8 +781C/T exhibited a significant co-relation in TB patients when symptoms were examined. Additionally, the combined effects of the two SNPs were investigated, and it was discovered that the 3-risk allele has a strong association with tuberculosis. Therefore, the polymorphisms mentioned earlier, which may also be influenced by ethnicity, may significantly impact the chance of developing tuberculosis.