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

Abstract

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.

Distortion of the Self-Reactive IgG Antibody Repertoire in Multiple Sclerosis as a New Diagnostic Tool

“…However, no representative pattern of immune recognition could be associated with these pathophysiological processes. By contrast, patients with myasthenia gravis share similar immune recognition patterns of both purified IgM and IgG to self-Ags extracted only from the target tissues (thymus and muscle) (43,44). These data suggest that organ-specific autoimmune diseases might be associated with an alteration of immune recognition of target organs (18).…”

Myasthenia gravis associated with autoimmune thyroid disease: A report of two patients

“…First, OMG and GMG might actually represent separate diseases. 15,16 Second, an immunological cross-reactivity against epitopes or autoantigen shared by the thyroid and the eye muscles might be the basis for this association. 17,18 Several experimental data suggest that the thyroid antigens are presents in ocular tissues.…”

Ocular myasthenia gravis associated with euthyroid ophthalmopathy

“…In ocular MG, AChR antibodies tend to be present in low titer, and were not found in one-third of a patient population studied. 13 Ocular MG patients showed minimal, unstable sensitization of anti-AChR CD4 ϩ T cells. 12 Even in seronegative MG, plasma from generalized seronegative MG showed inhibition of AChR function, whereas that from ocular seronegative MG did not.…”