The relationship between the clinical course of SARS-CoV-2 infections and ACE2 and TMPRSS2 expression and polymorphisms

Background. The viral spike (S) protein and host ACE2 and TMPRSS2 genetic variations may act as a barrier to viral infections or determine susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Objectives. We investigated the relationship between the expression patterns and polymorphisms of the ACE2 and TMPRSS2 receptor genes associated with coronavirus disease 2019 (COVID-19) and the clinical course of SARS-CoV-2 infections. Materials and methods. We examined 147 COVID-19 patients (41 asymptomatic, 53 symptomatic and 53 cases treated in the intensive care unit (ICU)) and 33 healthy controls. The ACE2 and TMPRSS2 expression was determined using the One-Run RT-qPCR kit. Genotypic distributions of single nucleotide polymorphisms (SNPs) of ACE2 and TMPRSS2 were obtained using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Results. The expressions of ACE2 and TMPRSS2 were different between SARS-CoV-2-positive and -negative groups. The ACE2 rs714205GG genotype and G-allele showed significant differences in the asymptomatic SARS-CoV-2-positive group. A significant correlation was found between the expression of TMPRSS2 rs8134378GA, rs2070788GA, rs7364083GA, and rs9974589AC genotypes and SARS-CoV-2 positivity. The rs1978124 C-allele and rs8134378 A-allele expressions were significant in the symptomatic SARS-CoV-2-positive group. The TMPRSS2 rs2070788GA expression was different in all patient groups compared to the control group. There was a difference between SARS-CoV-2-positive and -negative groups regarding the CTTA haplotype formed by ACE2 variants. The AGCAG and AGAAG haplotypes formed by the TMPRSS2 variants were more common in the asymptomatic patient group than in other patient groups. Conclusions. Identifying the relationship between host genetic variants and COVID-19 susceptibility will contribute to further studies, enabling new vaccines and potential therapeutic approaches to be discovered.