INTERLEUKIN-6 RECEPTOR EXPRESSION IN THE PERIPHERAL B-CELLS OF PATIENTS WITH MULTICENTRIC CASTLEMANS-DISEASE

Interleukin-6 (IL-6) is an important regulator of terminal B-cell diff erentiation. Inappropriate over-synthesis of IL-6 may play a primary r ole in the pathogenesis of multicentric Castleman's disease (MCD). We investigated the expression of the IL-6 receptor (IL-6R) in peripheral B cells from three patients with MCD, as well as the responsiveness o f these cells to IL-6. Flow-cytometric analysis showed that IL-6R was significantly expressed on the peripheral B cells of two of three pati ents. The B cells expressing IL-6R spontaneously produced increased le vels of immunoglobulin G (IgG). IL-6R-expressing B cells from one pati ent showed hyper-responsiveness to IL-6.