Polymorphism in promotor region of IL6 gene as a predictor for severity in COVID -19 patients

SARS-CoV-2 is the causative agent of coronavirus disease started in 2019 (COVID-19). IL-6 gene is located on chromosome 7. A considerable number of polymorphisms was identified in the IL-6 gene. Polymorphism in IL-6-174C allele is associated with a higher level of IL-6 production and this may lead to severity of in COVID-19 patients. We intended to investigate the role of polymorphism in the promotor region of IL-6 gene as a predictor for disease severity in COVID-19 patients. Fifty patients diagnosed with COVID-19 and classified into moderate and severe groups and twenty apparently healthy controls were enrolled in the study. Genotyping for IL-6 gene (-174G/C) was done by using TaqMan SNP genotyping assay for all studied groups. The distribution of different IL-6-174G/C genotypes among COVID-19 patients was 76% for GG genotype, 22% for GC genotype and 2% for CC genotype. Whereas the distribution of genotypes among the control group was 80% for GG genotype, 20% for GC genotype and 0.0% for CC genotype. The G allele distribution was 87% and 90% in the patients and control groups, respectively, while the C allele was 13% and 10% in the patients and control groups, respectively. There was no significant statistical association between different genotypes, severity and treatment outcome in the patients group. In conclusion, this study showed no relation between -174G/C IL-6 gene polymorphism and disease, in COVID-19 patients. Keywords: Interleukin-6, Promotor region, Polymorphism, COVID-19, Severity.