ABSTRACT
Severity of symptoms in COVID-19 has been shown to result from a cytokine storm. Interleukin (IL)-17 is one of these various cytokines, which results in a proinflammatory response, systemic inflammatory symptoms, inflammatory cell infiltration of lung tissue and thus leads to the massive lung pathology and multiorgan failure. Gene polymorphisms in the regulatory regions of cytokine-encoding genes affect the amounts of cytokines produced and possess a fundamental role in infectious diseases. This study aimed to investigate the role of IL-17A (rs2275913;G197A) gene polymorphism as predictor of disease severity and its correlation with IL-17 serum levels in COVID-19 patients. A group of 70 COVID-19 patients and 17 age and sex-matched control subjects were enrolled in the present work. Patients were classified into two groups moderate, severe and acute respiratory distress (ARDS) cases, defined according to the criteria established by the world health organization. Quantitative real time-polymerase chain reaction was done to detect IL-17A (rs2275913;G197A). Serum IL-17 levels were assessed by an enzyme-linked immunosorbent assay in both patients and controls. The distribution of different IL-17A G/A genotypes among COVID-19 patients were 44.3% for GG genotype, 44.3% for AG genotype and 11.4% for AA genotype. Genotypes among the control group were 43.8% for GG genotype, 50% for AG genotype and 6.3% for AA genotype. G allele distribution was 66.4%, 68.8% in patient and control group, respectively, and A allele was 33.6% and 31.3%, respectively. There was no association between the different genotypes, disease severity or IL-17 serum levels in the patient group. In conclusion, despite the possible role of IL-17 in the pathogenesis of inflammation, there was no association between IL-17 polymorphism and disease severity or IL-17 serum levels among Egyptian COVID-19 patients.