The effect of chemokine gene variants on COVID-19 disease severity

Comprehensive research has been carried out on the progression and treatment of the COVID-19 disease, which has been declared a pandemic all over the world, but the fact that the virus causes different disease severity in infected individuals has still not been fully clarified. It has been shown in studies that the immune profile is important in the response to the virus and especially chemokines play an important role in determining the severity of the COVID-19 disease. We included 60 mild, 59 severe and 60 critical COVID-19 patients in our study. By examining the chemokine polymorphisms of MCP-1-A2518G, SDF-1-3'A, CCR5- delta32, CCR5-A55029G, CXCR4-C138T and CCR2-V64I, the relationship between the responses of immune system cells against the virus and the severity of the disease that develops in individuals. We aimed to establish Polymerase chain reaction (PCR)/Sanger sequencing analysis was performed to detect variations. As a result of our study, it was observed that carriers of the MCP-1-A2518G G allele were observed quite frequently in the critically ill group, and the GA genotype was significantly higher in the critically ill group when compared in mild and critically ill groups. Similarly, GA genotype was found to be more common in the severe patient group than in the mild patient group. Comparing the critical and mild patient groups for the CCR2-V64I wt allele, the wt/wt genotype was found to be significantly lower in critically ill patients. Similarly, when the critical and severe patient groups were compared, it was observed that the 64I/64I genotype was significantly higher in the critically ill group. We did not find any significant results in other chemokine polymorphisms that we associate with COVID-19 disease severity. In conclusion, our study data showed that MCP-1-A2518G and CCR2-V64I polymorphisms are associated with increased severity of COVID-19 disease. However, larger studies focusing on gene expression levels in different populations will help to better understand this mechanism role.