IGA AUTOANTIBODIES AGAINST HUMAN EYE MUSCLE ANTIGEN DETECTED BY WESTERN BLOTTING AND IMMUNOHISTOCHEMICAL METHODS IN GRAVES-DISEASE

The presence of IgA autoantibodies against human eye muscle was invest igated in 40 patients with Graves' disease (33 had ophthalmopathy), Ig A anti-eye muscle antibodies could be demonstrated in sera of patients using western blotting and immunohistochemical methods, For the detec tion of sera possessing autoantibodies against eye muscle antigen the indirect immunosorbent assay had been used. IgA anti-eye muscle antibo dies could be demonstrated in 25 cases and lgG types in 16 cases out o f 40 patients. These anti-muscle autoantibodies were associated with e ye muscle rather than skeletal muscle, the number of positive cases wi th the latter being 5/40 for IgG and 2/40 for IgA. Immunoreactive band s of IgA autoantibodies against eye cytosol were found at 84, 64, 45, 40 and 25-23 kDa in 22, 2, 16, 2 and 18 cases, respectively. A differe nce was observed in the staining of IgG and IgA types of autoantibodie s by immunohistochemical analysis of eye muscle tissue. The IgA anti-e ye muscle antibodies reacted with muscle fibers and the IgG types show ed staining on endomysium, No sera of Graves' disease patients gave st aining on skeletal muscle tissue. The results supported the presence o f IgA anti-human eye muscle antibodies in patients with Graves' ophtha lmopathy, which might play a relevant role in the development of eye d isease.