In particular, one of these earlier studies indicated that DR2, a serologic correlate of HLA-DRB1*15 and, generally much less frequently, HLA-DRB1*16 gene products, appeared to be over-represented in IPF subjects (45), a finding which may be congruent with the current results. This evidence concerns the gene HLA-DRB1 and idiopathic pulmonary fibrosis.