Features of the frequency of occurrence of T-330G <i>IL2</i> gene polymorphism in patients with COVID-19

Abstract

SARS-CoV-2 infection is the etiopathogenetic factor of the new coronavirus infection. Susceptibility to the virus and, accordingly, the incidence differs in children and adults. On the one hand, this reflects the age-related features of the immune response. On the other hand, it is realized through the production of a number of cytokines, including IL-2, and reflects the genetically determined features of cytokine production. The aim of the study was to analyze the frequency of occurrence of T-330G polymorphic variants of the IL2 gene in patients with a new coronavirus infection. A total of 145 patients were examined, including 31.0% of children (n = 45) and 69.0% of adults (n = 100). The diagnosis of a new coronavirus infection was verified by RT-PCR confirming the presence of the SARS-CoV-2 virus and identifying clinical symptoms of an upper respiratory tract infection. The control group consisted of 50 healthy volunteer donors. Allele-specific PCR with electrophoretic detection in 3% agarose gel (Litech, Russia) was used to analyze the T-330G polymorphism of the IL2 gene. To compare the frequencies of allele combinations, the χ2 test and the odds ratio OR and (95% CI) were used.The dominant genotype in patients with COVID-19 was the heterozygous GT genotype of the T-330G polymorphism of the IL2 gene. In the group of children at risk of developing a new coronavirus infection, the GG genotype of the T-330G polymorphism of the IL2 gene was associated (31.1% in children and 18.0% in the control group, p < 0.05, OR = 2.047). While the homozygous TT genotype of the T-330G polymorphism of the IL2 gene was a protective genotype (its occurrence rate was 26.7% in patients, 54.0% in the control group, p < 0.05, OR = 0.315). In adults, the heterozygous GT genotype of the T-330G polymorphism of the IL2 gene was associated with the risk of developing a new coronavirus infection (in the group of patients – 44.0% versus control – 28.0%, p = 0.028, OR = 2.020). A low risk of developing the disease was associated with the homozygous TT variant of the T-330G polymorphism of the IL2 gene (in the group of patients 37.0% versus control – 54.0%, p = 0.024, OR = 0.500).The T-330G polymorphism of the promoter zone of the IL2 gene differently affects its production. The direction of the immune response and its effectiveness depend on the level of IL-2. Understanding the individual factors that determine the features of the immune response can help in understanding the mechanisms of development of COVID-19-associated diseases and the selection of approaches to personalized methods of their treatment.