In summary, we demonstrated a lack of an “intermediate” HLA-DRB5+ Plasma B and abnormal IGHG4+ Plasma B in peripheral blood and a lack of HLA-DRB5 expression as well as impaired “antigen processing and presentation activity” on memory B cells in ST of ACPA- RA. The gene discussed is HLA-DRB5; the disease is rheumatoid arthritis.