Increased production of B cell growth factor (BCGF) in Sjögren's syndrome

The objective of this investigation to clarify possible roles of B cell growth factor (BCGF) in the abnormal activation of B cells in Sjögren's syndrome (SS). Lymphocyte subsets of peripheral blood from 20 patients with SS (14 with primary SS and six with secondary SS) and 11 healthy donors were analysed by flow cytometry. Supernatants of peripheral blood T cells obtained from patients with SS and from donors, cultured with or without PHA, were studied using bioassay with a B cell line, KS-3.F10. The number of CD20+ cells and CD4+DR+ cells was significantly increased in SS patients compared with healthy donors. T cells from SS patients showed increased production of BCGF, whether or not they were stimulated with PHA. The enhancement of BCGF production by PHA had a positive correlation with the percentage of CD4+CD45RA+ cells, and a negative correlation with the focus score of lip biopsy. Our experiments showed that BCGF production by T cells was spontaneously increased in SS patients. The accelerated BCGF production with PHA stimulation may be related to the increase of CD4+CD45RA+ cells and the decrease of the inflammation determined by the grade of cell infiltration into salivary glands, but not by the increase of CD20+ cells.