title: Circulating activated B cells in primary biliary cirrhosis.
abstract: Since patients with primary biliary cirrhosis (PBC) have evidence of abnormal function of the humoral immune system, we determined if B cells from patients with this disease show evidence of activation and can be stimulated by polyclonal activators. Using a reverse hemolytic plaque assay, it was found that patients with PBC had a significant increase in the number of circulating immunoglobulin-secreting cells, compared to normal controls and patients with chronic type B hepatitis virus (HBV) infection. However, the total number of activated cells was less than 1% of the total circulating B-cell population. Furthermore, we were unable to detect an increase in the expression of transferrin receptors, a membrane receptor associated with B-cell activation, in the majority of B cells in patients with PBC. In other studies, immunoglobulin production by lymphocytes from patients with PBC, when stimulated with the polyclonal activators pokeweed mitogen and Epstein-Barr virus (EBV), was reduced. This hyporesponsiveness was not due to a decrease in the number of B cells, as determined by staining with the monoclonal antibody anti-Leu 12. Furthermore, the decreased response to B cells to polyclonal activation in PBC patients was not due increased suppressor T-cell function, since EBV-simulated cultures of lymphocytes from patients with PBC demonstrated diminished suppression of immunoglobulin-secreting cells after 14 days of culture compared to controls. These findings suggest that the humoral abnormalities in PBC are due to the activation of a small subpopulation of B cells rather than to generalized B-cell hyperactivity.
mesh_terms: D000921:Antibody-Producing Cells / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D006509:Hepatitis B / Q000276:immunology; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000276:immunology*; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D011043:Pokeweed Mitogens / Q000494:pharmacology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D011043:Pokeweed Mitogens