Expression ofCD 21,CD 22,andthemouse erythrocyte receptor on peripheral Blymphocytes in rheumatoid arthritis

SUMMARY Theexpression oftheB cell antigens, CD 21,CD 22,andthemouse erythrocyte receptor (MER), on peripheral mononuclear cells (PMC)in61patients withrheumatoid arthritis (RA)andin25patients withvarious other formsofrheumatic disease was studied. Patients with RA showedsignificantly more peripheral B cells thancontrol patients, whereasthere was no difference between patients withRA andcontrols inresting B cells expressing theMER or resting andactivated B cells expressing CD 21.Patients withactive RA hadsignificantly less MER positive andmore CD 21positive B cells thanpatients withinactive disease. Therelation between disease activity andexpression ofMER andCD 21was independent ofdrugtreatment orproduction ofclassical rheumatoid factor. Thesedata may beinterpreted as a signofB cell activation inRA.Inaddition, patients withseronegative RA receiving goldtreatmentshowed significantly more MER positive cells thanpatients receiving different drugs, whereas patients receiving non-steroidal anti-inflammatory drugs(NSAIDs) alonehadsignificantly more CD 21 positive cells. This may betheresult ofdifferent immunomodulating effects ofdrugs on B cell subsets.