Repertoires of autoantibodies against homologous eye muscle in ocular and generalized myasthenia gravis differ.

If weakness of the eye muscles remains the only symptom of myasthenia gravis (MG) for more than 2 years, the condition is operationally defined as ocular MG (OMG). A number of clinical, genetic, and immunological differences between this variant and generalized MG (GMG) have been described. We analyzed repertoires of autoantibodies against proteins of skeletal and extraocular muscle in sex- and age-matched groups of patients with either GMG or OMG (n = 10 in each group). All GMG sera detected a group of three proteins larger than 200 kDa which were not detected by any of the OMG sera. Two components with apparent molecular weights of 50 and 60 kDa were stained by seven of the ten OMG sera but by none of the GMG group. These antigens are probably soluble, cytoplasmatic proteins of the eye muscle. OMG sera, furthermore, detected a protein of about 45 kDa in the pellet fraction of eye muscle but failed to do so after adsorption with skeletal muscle fractions. We conclude that OMG and GMG sera contain autoantibodies of different specificities. Our findings further support immunological heterogeneity in MG.