DPP9 and pulmonary fibrosis: Beyond ABO, a locus in the dipeptidyl peptidase 9 (DPP9) gene associated at p < 1 × 10−5 with severe COVID-19 was identified as being shared with a GWAS of fibrotic idiopathic interstitial pneumonia [92] and a recent GWAS of the most severe form of that group of diseases, idiopathic pulmonary fibrosis (IPF) [19].