HLA-DRB1 and COVID-19: Interestingly, two alleles (HLA-A*02:01, B*18:01) of this haplotype are also part of the HLA haplotype, HLA-A*02.01g-B*18.01g-C*07.01g-DRB1*11.04g, which in Italy has a regional distribution inversely correlated with both the incidence and mortality of COVID-19 (51).