HLA-DRB1 and idiopathic interstitial pneumonia: In addition to HLA-DRB1 and HLA-DQB1, other HLA genes with rare deleterious variants were also significantly associated with IPF in our study, including HLA-DRB5, HLA-A, HLA-B, HLA-H, HLA-G, HLA-DQA1 and HLA-L.