CD79A and rheumatoid arthritis: •Serum anti-MAA (IgA, IgG, IgM) antibody positivity (≥95th or 98th percentile in controls) observed in 0.6% to 14.8% of RA participants•Meta-analysis estimated anti-MAA IgG positivity among RA to be 38.5% [95% CI: 20.4%-60.3%]