Interferon-lambda 3 is involved in the permission of pneumonia development after infection with respiratory viruses including SARS-CoV-2

Background: The effectiveness of barrier function of the respiratory mucosa largely depends on interferons type I (IFNs-α/β) and type III (IFNs-λ) The IFNs-λ forms the first level of innate immune protection The single-nucleotide polymorphisms (SNPs) affecting IFN- λ3 production were found previously The study aimed to investigate a putative association of SNPs rs8099917 T/G located upstream IFNL3 gene and rs12979860 C/T within IFNL4 gene with a risk of pneumonia developing after infection with respiratory viruses Methods: The nasopharyngeal swabs, lavages, and blood samples from 318 patients infected with respiratory viruses were analyzed Of these, 168 participants were shown to have community-acquired pneumonia, while the rest patients were diagnosed with bronchitis The respiratory virus genomes were detected by real-time polymerase chain reaction (PCR) using commercially available kits The DNA samples from all patients were used to detect SNPs rs8099917 T/G and rs12979860 C/T by real-time PCR using a commercially available kit COVID-19 morbidity and mortality data were obtained from the WHO website Results: No association was found between different rs8099917 allelic variants and the development of pneumonia The rs12979860 TT genotype was significantly more often detected in patients with pneumonia (p = 0 039;OR = 2 400;95% CI 1 310 - 3 706) IFN-λ3 production has been early found to be maximal with rs12979860 TT genotype An association was established between rs12979860 T allele frequency and COVID-19 mortality rate in 13 countries Conclusions: The rs12979860 TT genotype is a genetic marker of increased risk of pneumonia after infection with respiratory viruses High T allele frequency may be an indicator of a higher COVID-19 mortality rate Patients with rs12979860 TT genotype have an increased risk of developing COVID-19 pneumonia