[Production and role of B cell growth factor (BCGF) in Sjögren's syndrome].

Sjögren's syndrome (SS) is characterized by polyclonal B cell hyperactivity in exocrine glands and peripheral blood. The number of CD20+ B cells is significantly increased in peripheral blood of twenty patients with SS in our study. LMW-BCGF (12 KD) cloned by Sharma in 1987 was reported to associate with DNA synthesis and to give the progressive signal of B cell cycle which develop G1 stage to S stage. In our bioassay using Ks-3, F. 10 cells which respond only to BCGF and proliferate, T cells from SS patients showed increased production of BCGF, whether or not T cells were stimulated with PHA. It was suggested that BCGF may play an important role in the polyclonal activation of B cells in SS.