WAKMAR2 and rheumatoid arthritis: Proliferation of CD4+ T cells and expression of TRAP in monocytes/macrophages were higher after they were co-cultured with RA FLS with WAKMAR2 silencing (Supplementary Figure 3A), whereas the proliferation of CD4+ T cells and the expression of TRAP in monocytes/macrophages were lower after they were co-cultured with RA FLS with WAKMAR2 overexpression (Supplementary Figure 3B).