Wegener's granulomatosis. Electron microscopic and immunofluorescent studies.

We report a case of classic Wegener's granulomatosis. Direct immunofluorescent study showed finely granular deposits of IgG and IgM in some of the alveolar walls, and of IgM in the maxillary sinus arteries. Electron-microscopic study of the lung and maxillary sinus showed intravascular fibrin, but failed to demonstrate electron-dense deposits in the blood vessel walls. Our patient also had circulating cryoglobulins, consisting of IgG, IgM, Clq, and C3, and evidence of circulating immune complexes as demonstrated by the Clq-binding test. These findings suggest that circulating immune complexes may play an important role in the pathogenesis of the respiratory lesions of Wegener's granulomatosis.