[Mechanism of activation of B lymphocytes in idiopathic UIP: evaluation of BCGF and BCDF-production from blood T lymphocytes]

Abstract

The activation of B lymphocytes and formation of immune complexes were suggested to play important roles in the pathogenesis of idiopathic UIP. To investigate the mechanism of the activation of B lymphocytes, we studied the production of B cell growth factor (BCGF) and B cell differentiation factor (BCDF) in patients with idiopathic UIP and those with IP-CVD, in comparison with healthy controls. Culture supernatants of peripheral blood mononuclear cells from patients with idiopathic UIP induced more IgM- and IgA-production than those from healthy controls, indicating a higher production of BCDF. Culture supernatants of peripheral blood mononuclear cells from patients with idiopathic UIP did not induce higher proliferation of B lymphocytes than those from healthy controls, indicating that production of BCGF was not enhanced in the patients. Increase of production of BCGF and BCDF from patients with IP-CVD was not observed. From these results, it was suggested that T lymphocytes that release lymphokines like BCDF are activated in patients with idiopathic UIP, but not in those with IP-CVD, and that the process of activation of B lymphocytes might be different between these fibrotic diseases.