Expression of CD 21, CD 22, and the mouse erythrocyte receptor on peripheral B lymphocytes in rheumatoid arthritis.

The expression of the B cell antigens, CD 21, CD 22, and the mouse erythrocyte receptor (MER), on peripheral mononuclear cells (PMC) in 61 patients with rheumatoid arthritis (RA) and in 25 patients with various other forms of rheumatic disease was studied. Patients with RA showed significantly more peripheral B cells than control patients, whereas there was no difference between patients with RA and controls in resting B cells expressing the MER or resting and activated B cells expressing CD 21. Patients with active RA had significantly less MER positive and more CD 21 positive B cells than patients with inactive disease.