Immune complex deposits in Graves' disease and Hashimoto's thyroiditis.

The thyroid glands of four patients with Graves' disease and five patients with Hashimoto's thyroiditis were investigated to demonstrate in vivo immune complex deposition. By electron microscopy, electron-dense deposits were observed in the follicular basal lamina--basement membrane--(FBL) often associated with lymphocytic and plasma cell infiltration. A positive correlation was obtained with all cases by immunofluorescent studies using anti-IgG, IgA, IgM, C3 and antithyroglobulin conjugated serums. The staining was of a granular pattern and coincided to the FBL region. No discrepancies were noted in electron microscopic and immunofluorescent observations between patients with Graves' disease and Hashimoto's thyroiditis, and the occasional observation of immune complexes in areas devoid of infiltrate in some patients with Graves' disease. Morphologically, the deposits were found to be similar to those described in the Obese Strain chickens with spontaneous autoimmune thyroiditis.