PDCD1 and rheumatoid arthritis: Our KEGG enrichment analysis found that SASH3 may participate in Natural killer cell-mediated cytotoxicity, Th17 cell differentiation, Hematopoietic cell lineage, Osteoclast differentiation, Rheumatoid arthritis, Th1 and Th2 cell differentiation, Toxoplasmosis, T-cell receptor signaling pathway, Inflammatory bowel disease, Type I diabetes mellitus, Primary immunodeficiency, PD-L1 expression and PD-1 checkpoint pathway in cancer, Graft-versus-host disease, NF-kappa B signaling pathway, B-cell receptor signaling pathway, and Toll-like receptor signaling pathway.