This study contrasts immune checkpoint inhibitor-induced myasthenia gravis (ICI-MG) with idiopathic MG by analyzing AChR autoantibodies. Among three patients with ICI-MG, only one exhibited complement activation and modulation/blocking capabilities akin to idiopathic MG, hinting that AChR autoantibodies may not be pivotal in the disease pathology of the other two. This observation questions the reliability of serological testing as the sole diagnostic tool for ICI-MG and underscores the necessity for thorough clinical evaluations to assess ICI-related adverse events.

Myasthenia gravis is usually diagnosed by detecting AChR autoantibodies, present in about 85% of cases. These autoantibodies impair neuromuscular transmission through various mechanisms. Although ICIs have transformed cancer therapy, they also lead to severe immune-related adverse events (irAEs), such as ICI-induced MG, which has a high mortality rate due to potential involvement of skeletal and cardiac muscles. This research probes the immunopathology of ICI-MG by exploring the autoantibodies’ binding capacity, effector functions, and epitope specificity, highlighting distinct differences in the pathogenic roles of AChR autoantibodies in ICI-MG compared to idiopathic MG.

Reference: Masi G, Pham MC, Karatz T, et al. Clinicoserological insights into patients with immune checkpoint inhibitor-induced myasthenia gravis. Ann Clin Transl Neurol. 2023 May;10(5):825-831. doi: 10.1002/acn3.51761. Epub 2023 Mar 16. PMID: 36924454; PMCID: PMC10187728.