HLA-C and COVID-19: In conjunction with the results of an in silico analysis that the HLA-C*04:01 allele is one of the least efficient for SARS-CoV-2 peptide presentation (26), our aforementioned findings suggested that the scanty HLA class I heterozygosity and SARS-CoV-2 peptide presenting ability in COVID-19 cases with clinical symptoms may be driven by the stronger association of the HLA-C*04:01 with the disease severity.