Distribution of HLA class II allelic variants in patients with COVID-19 in Latvia

This study assessed the distribution of HLA Class II allelic variants in patients with COVID-19 in the Latvian population. The study has been conducted within the framework of the National Research Program VPP-COVID-2020/1-0023. The study included 68 patients with Covid-19 (mean age 56±16 years, 51% females). HLA typing was performed in HLA-DRB1, -DQA1, and -DQB1 loci by PCR with low-resolution sequence-specific primers (DNA-technology). The distribution of HLA alleles in patients with COVID-19 was compared to the distribution of frequency of alleles in a reference group of 100 Latvian individuals, previously typed in our laboratory. The effect of each allele was assessed by calculation of the odds ratio. In patients with COVID-19, HLA-DRB1*07:01, HLA-DRB1*13:01, HLA-DRB1*15:01, and HLA-DQA1*01:03 alleles were found more frequently than in the reference group. These alleles can be candidates associated with a higher susceptibility to the SARS-CoV-2 virus in our population and can be considered as risk alleles. HLA-DRB1*15:01 was identified as a risk allele in patients with COVID-19 in a recent study in Italy. Three alleles were found rarely than in the reference group. There were HLA-DRB1*12:01, HLA-DRB1*16:01, and HLA-DQB1*03:03. These alleles can be associated with a protective effect on SARS-CoV-2 infection. The preliminary data of HLA typing of patients with COVID-19 reveal some allelic variants of HLA Class II genes responsible for susceptibility or protection to SARS-CoV-2 infection in the Latvian population. In the further stage of the project, we plan to perform HLA typing of about 120 patients with COVID-19 to confirm the results and to identify haplotypes associated with susceptibility and protection.