B-cell Growth-promoting Activity in Supernatants from CD4+ Cells from Synovial Fluid and Peripheral Blood of Patients with Rheumatoid Arthritis and Other Inflammatory Arthritides

Abstract

The purpose of this study was to compare CD4+ cells from peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis with regard to mitogen-induced production of B-cell growth-promoting activity. CD4+ cells were isolated by a direct immunomagnetic technique and supernatants from both unstimulated and mitogen-stimulated CD4+ cells were studied. B-cell growth-promoting activity was assayed using highly purified B cells obtained from peripheral blood of healthy individuals. The indicator B cells were isolated by an indirect immunomagnetic technique and solid-phase anti-n was used for activation of the B cells. Supernatants of unstimulated CD4+ cells from SF and PB did not contain B-cell growth-promoting activity, while usually high levels of B-cell growth-promoting activity were detected in the supernatants from mitogen-stimulated cultures. There was no significant difference in the B-cell growth-promoting activity level between supernatants from SF CD4+ and patient PB CD4+ cells, nor was there any significant difference between SF CD4+ and control PB CD4+ supernatants. The results indicate that the CD4+ cells in the SF have a normal potential for producing B-cell growth-promoting activity.