Differences in Fine Specificity of Anti-Acetylcholine Receptor Antibodies between Subgroups of Spontaneous Myasthenia Gravis of Recent Onset, and of Penicillamine Induced Myasthenia

Abstract

The antigenic specificity of anti-acetylcholine receptor antibodies (anti-AChR) from 70 recent onset myasthenia gravis (MG) and nine penicillamine MG patients was determined by inhibition experiments using monoclonal antibodies (m.abs) raised against human AChR.

Differences were found between individuals and between the three clinical subgroups of idiopathic MG distinguished by age of onset, thymic pathology and HLA associations. Pencillamine-induced MG anti-AChR differed from that in age-matched MG controls but was similar to that in young-onset cases.

The variable and heterogeneous antigenic specificity in MG suggests that AChR itself rather than a cross-reacting epitope is the primary antigen. Differences in specificity between MG subgroups may reflect a diversity of triggering factors or of immunoglobulin genes.

Key Words:

• Anti-acetylcholine receptor antibodies
• antibody specificity
• autoimmunity
• myasthenia gravis subgroups
• thymoma
• penicillamine-induced