[Bound class M, A and G immunoglobulins in the thymus of myasthenia gravis patients].

Deposits of granular material containing IgM, IgA, and IgG were revealed in the thymus of patients with myasthenia by direct immunofluorescence. Treatment of the thymus sections by unlabeled preparations against individual classes of human immunoglobulins inhibited the reaction of the granular material with the homologous labeled preparations. Disappearance of fluorescence of these deposits was also seen in treatment of the sections with glycine-HCl-buffer, pH 2.8. These data permitted a suggestion that granular material represented immune complexes where IgM, IgA, and IgG served as antibody, and thymus tissue components--as an antigen. The presence of bound immunoglobulin in the thymus indicated that an autoimmune process directed against the tissues of this organ occurred in myasthenia.