IL-2 ENHANCES POLYCLONAL IGM BUT NOT IGM-RHEUMATOID FACTOR SYNTHESIS BY ACTIVATED HUMAN PERIPHERAL-BLOOD B-CELLS

IgM-rheumatoid factor (RF) is thought to be involved in the pathogenes is of rheumatoid arthritis (RA). Several cytokines are known to regula te immunoglobulin synthesis. In this study the effects of IL-2 on poly clonal IgM and IgM RF synthesis were compared. Cytokines were added to peripheral blood B cells from normal subjects and patients with RA af ter activation by Staphylococcus aureus Cowan 1 (SAC). The addition of IL-2, but not IL-4 or IL-6, resulted in significant enhancement of Ig M synthesis in cultures from both healthy subjects and patients with R A. Similar degrees of enhancement were seen in both peripheral blood m ononuclear cell and highly purified B cell cultures. IgM-RF was synthe sized after activation in cultures from healthy subjects and spontaneo usly in cultures from RA patients. In contrast to polyclonal IgM synth esis, IL-2 failed to augment IgM-RF synthesis in cell cultures from ei ther healthy subjects or RA patients. This study demonstrates differen t effects of IL-2 on IgM and IgM-RF synthesis.