HLA-DRB1 and idiopathic pulmonary fibrosis: There were no apparent associations between the presence (n = 91) or absence (n = 184) of DRB1*1501 among the IPF patients and either age (66±1 vs. 67±1 years) or gender (75% vs. 73% males), for the DRB1*1501+ and DRB1*1501null subjects, respectively.