Analysis of KIR and HLA Polymorphism in Chinese Individuals With COVID-19.

Killer-cell immunoglobulin-like receptor (KIR) interactions with HLA class I have crucial roles in modulating NK cell function in response to viral infections. To explore the correlation between KIR/HLA and susceptibility to SARS-CoV-2 infection, we analysed polymorphism of KIR genes, haplotypes, HLA allotypes, and the interplay between KIR and HLA in individuals diagnosed with COVID-19. Compared to a population control group, we observed a significantly increased frequency of KIR3DL300802 in the COVID-19 group. When encoded by the HLA-B gene, the frequency of HLA-Bw4, a ligand for KIR3DL1, was at lower frequency in the COVID-19 group. Additionally, significantly elevated frequencies of KIR-Bx3, KIR3DL300301, 3DL3048, and C1HLA-C were identified in the COVID-19 group before multiple test correction, suggesting associations with susceptibility to SARS-CoV-2 infection. Our findings indicate that the KIR3DL300802 allele may be a high-risk factor for SARS-CoV-2 infection, while Bw4 encoded by HLA-B gene may confer protective effects against the infection.