In addition, we used the widely applied single sample gene set enrichment analysis method to analyze the gene set enrichment scores of nine immune cell types (70), including B cells, CD4+ T cells, CD8+ T cells, dendritic cells, macrophages, mast cells, NK cells, plasma cells, and CD4+ TPH cells, in the synovial tissue microenvironment of RA and OA (71) by using the representative gene sets derived from single-cell transcriptome data of RA synovium (11) (supplemental Table S8). Here, CD8A is linked to rheumatoid arthritis.