Representative data for the differences in Th cell subsets between two IPF patients with non-PF-ILD or PF-ILD phenotypes are shown in Fig. 1C. The proportion of Th2 cells, defined by the expression of surface markers CD4+CD45RA−CXCR5−CD25low−intermediateCCR6−CXCR3−, was increased in the BALF of patients with the PF-ILD phenotype (44.5%) compared to the non-PF-ILD phenotype (9.02%). Here, CD4 is linked to idiopathic pulmonary fibrosis.