The severity of COVID-19 infection correlation with IL-17 polymorphism

Single nucleotide polymorphisms (SNPs) in many studied genes have been related to the severity of COVID-19. This study was carried out to investigate whether the polymorphisms of two SNPs (rs763780 and rs2275913) of the gene polymorphisms for Interleukin 17 (IL-17) are connected to the COVID-19 severity. The effect of these polymorphisms on the levels of IL-17 and the relationship between the level of IL-17 and the severity of COVID-19 were also investigated. The real-time polymerase chain reaction (RT-PCR) was performed to detect SARS-COV-2. Blood samples were obtained for the analyses of IL-17 levels by enzyme-linked immunosorbent assay, and Genomic DNA was extracted for genotyping. It should be noted that genotyping was performed using RT-PCR. The results indicated that the IL-17 level significantly increased in the case group, compared to the control group (healthy people), and there was a relationship between the severity of COVID-19 and IL-17 levels (P<0.01) in the severity groups. Mean±SE values of IL-17 were 67.99±2.05, 147.60±3.34, 218.15±6.27, and 283.97±5.59 ng/L for the control, mild, moderate, severe, and the critical group, respectively. Furthermore, the type of severity had a non-significant relationship with SNP80 and IL-17 levels (ng/L). Moreover, the type of severity also had a non-significant relationship with SNP13 and IL-17 levels (ng/L) (P≤0.05). In addition, the severity of COVID-19 and the prevalence of the AA genotype were shown to be significantly correlated. Besides, rs2275913 A-allele carriers were shown to be at risk (P=0.021) in the case group, compared to the control group. Furthermore, rs2275913 A-allele carriers were at a higher risk in the severe group (P=0.005, P >0.05) and critical group (P=0.023, P>0.05), compared to the mild group. There was no relationship (P<0.05) between the prevalence of the GA genotype and the severity of COVID-19. Among C-allele carriers of rs 763780 at IL-17, a strong association was discovered between the frequency of the TC/CC genotype and the severity of COVID-19 risk (P=0.0001, P>0.05). Both of them increased the risk in all groups, including the mild or moderate group (P=0.0001, P>0.05), the severe group (P=0.0001, P>0.05 for TC genotype and P=0.04, P>0.05 for CC genotype), and critical group (P=0.0001, P>0.05). According to the results, COVID-19 prognosis and severity were substantially correlated with IL-17 level and two IL-17 SNPs, rs2275913 and rs763780. It demonstrated that the two SNPs might be potential markers for the prediction of COVID-19 risk and development. The different levels of severity also had a non-significant relationship with SNP13 and SNP80 as well as IL-17 levels (ng/L).