H2BC9 and rheumatoid arthritis: In our enrichment analysis, differential genes, including H2bc9 and AABR07065750.2, were mostly associated with immune system diseases such as systemic lupus erythematosus, rheumatoid arthritis, and herpes simplex infection; the release of inflammatory cytokines and autoantibody production during the disease development leads to local and systemic bone loss (27).