Anti-acetylcholine receptor antibody related idiotypes in myasthenia gravis

Anti-acetylcholine receptor antibody associated idiotypes were defined by six murine monoclonal antibodies raised against purified receptor antibodies. Four of the monoclonal antibodies bound to idiotopes located within or close to the antigen binding site of the anti-receptor antibodies; the other two monoclonal antibodies were directed against framework determinants. These monoclonal antibodies recognized idiotopes present on immunoglobulins in 14-60% of patients presenting myasthenia gravis, indicating substantial idiotype sharing. These idiotopes were also found in patients with no detectable anti-receptor antibody activity in their serum. In all patients studied, the pattern of idiotypes fluctuated considerably during the course of the disease regardless of clinical symptoms. This suggests continuous modulation of the autoimmune process in myasthenia gravis.