HLA-DRB1 and hypersensitivity pneumonitis: Similar findings have been reported in a subset of HP patients who expressed the DRB1*03:01-DQB1*02:01 HLA haplotype that was associated with a significant risk of development of antinuclear antibodies (OR = 19.23; p = 0.0088), while expression of the HLA-DRB1*03:01 allele was associated with higher mortality (OR = 5.9; p = 0.043) (Buendía-Roldán et al., 2020).