B-lymphocyte response in peripheral blood of patients with pulmonary sarcoidosis

Sarcoidosis is a granulomatous disorder which can be characterized by various immunologic abnormalities including lymphocyte dysfunctions. The purpose of this study was to investigate the B-lymphocyte reactivity in the peripheral blood of 29 various patients with pulmonary sarcoidosis. A significant decrease in the production of IgG, IgM and IgA in supernatants of cultivated sarcoidosis B-cells both after stimulation with a T-cell dependent polyclonal B-cell activator (pokeweed mitogen) and with a T-cell independent polyclonal B-lymphocyte activator (Klebsiella pneumoniae) was seen, which suggested a disturbance in the B-cell differentiation of sarcoidosis patients. Those patients which were known to have a clinically active disease or a high intensity alveolitis in the bronchoalveolar lavage fluid showed a greater reduction in the B-cell differentiation response. Further evaluation of Ig-G subclasses displayed a significant decrease in the secretion of IgG1, IgG3 and IgG4. In contrast to the differentiation, the proliferation response of sarcoidotic peripheral blood lymphocytes to different mitogens did not differ from healthy controls.