HLA-DRB5+ memory B cells from ACPA- RA patients were absent for HLA-DRB5 expression and exhibited a lower transcriptional profile, with enrichment for “antigen processing and presentation”, “peptide antigen binding”, “peptide binding”, “antigen binding”, and “MHC class II receptor activity” compared with ACPA+ RA patients (Fig. 3c, e). The gene discussed is PRTN3; the disease is rheumatoid arthritis.