Bronchoalveolar mast cells in sarcoidosis: increased numbers and accentuation of mediator release.

Bronchoalveolar lavage was carried out in 36 subjects with sarcoidosis and 20 control subjects undergoing bronchoscopy for routine diagnostic purposes. The proportion of mast cells in the lavage fluid of subjects with sarcoidosis (mean (SE) 0.84% 0.09%; p less than 0.01) when compared with that of controls (mean 0.32% (0.05%); p less than 0.01). This increase was greatest in subjects with positive gallium scans but was not correlated with the percentage recovery of lymphocytes or radiographic stage. Anti-IgE induced histamine release from the bronchoalveolar cells of 15 subjects with sarcoidosis was significantly increased at all effective doses of anti-IgE. This accentuation of histamine release was significantly greater in patients with positive gallium scans and correlated directly with the percentage recovery of lymphocytes (r = 0.7, p less than 0.005). The dose-response curve of anti-IgE induced histamine release from bronchoalveolar cells of subjects with more than 20% of lymphocytes in the lavage cell population was significantly greater than the dose-response curves of subjects with fewer than 20% of lymphocytes and of controls.