PTGS2/COX2 was exclusively upregulated in SSc-PF lung tissues (Supplementary Table 4) and is a hub protein that interacts with TLR8, IRF1, ARG1, CAMP, LIF, MMP10, RCAN1, GGT1, EDN1, and MPO. This evidence concerns the gene RCAN1 and pemphigus foliaceus.