HLA-DRA and idiopathic pulmonary fibrosis: In our study, we also observed a significant increase in the expression levels of macrophage-related genes (ITGAM, ITGAX, MRC1, CD86, and HLA-DRA) and monocyte chemotaxis genes (CCL2 and CCR2) in the terminally fibrotic areas of the lungs of patients with IPF.