[Studies on Fc-receptor activity of pulmonary alveolar macrophage in granulomatous lung diseases].

A) An assay method for Fc-receptor activity of pulmonary alveolar macrophages (PAM) was studied by using SRBC coated with anti-SRBC antibody (IgG) under consideration of variable effects of several conditions on phagocytosis and rosette formation of sensitized SRBC (EA) by rabbit PAM. EA phagocytosis by PAM inhibited EA rosette formation of PAM. Significant number of EA phagocytosis was observed in FCA-activated PAM after incubation at 22 degrees C for 1 hr. Because Fc-mediated phagocytic potential of PAM was influenced by nonspecific phagocytic potential of PAM, Fc-receptor activity should be expressed by EA rosette forming activity of PAM measured in the condition of 4 degrees C for 20 hrs where phagocytosis was minimal. B) Fc-receptor activity of PAM increased significantly in rabbits with granulomatous lung lesions induced by BCG compared to normal rabbits, but not in lung lesions by M. faeni. C) Fc-receptor activity of PAM increased significantly in sarcoid patients compared to control patients. As Fc-receptor activity of PAM increased remarkably in the patients with active findings in chest X-ray films, increase of Fc-receptor, activity of PAM might suggest to reflect the active stage of sarcoidosis.