HLA-DRB1 and COVID-19: On the contrary, peptide 42766 (HLA-DRβ1*0101) induced the highest reactivity against its parental wild-type (Wuhan strain) peptide in Aotus, while its aa sequence (where residue N501 has become mutated in the UK, South African, Brazilian and some other strains) did not react with COVID-19 recovered sera due, perhaps, to tremendous virus-related genetic variability in this and some other RBD region residues.