Meanwhile, SPP1+ macrophages are observed in control lungs but comprise a higher proportion of the total macrophage population in more affected samples, and increased expression of SPP1 was associated with higher pathology scores (Fig. 5f, Supplementary Fig. 7 and Supplementary Tables 2, 7 and 8), suggesting an evolution of macrophage phenotypes characterizes progressive PF. This evidence concerns the gene SPP1 and pemphigus foliaceus.