SSC-ILD FCN1hi macrophages were associated with upregulated FcγR-mediated phagocytosis (FCGR1A, CTSL, MARCKS) and alternatively activated macrophage markers (MSR1, MRC1) (Fig. 1G, Supplementary Table S5b, available at Rheumatology online). Here, MRC1 is linked to interstitial lung disease.