Therefore, our findings confirmed the crucial role of MMP-2, MMP-7, MMP-9, and MMP-10 in RA-ILD+ and clarified that these together with two new relevant proteins, MMP-12 and TIMP-1, provide a useful combinatorial biomarker signature for the early diagnosis of ILD in patients with RA. This evidence concerns the gene MMP12 and rheumatoid arthritis.