From the Research
Inclusion body myositis (IBM) is associated with several autoantibodies, most notably anti-cN1A (cytosolic 5'-nucleotidase 1A) antibodies, which are found in approximately 30-40% of IBM patients, as well as anti-NDUFA11 autoantibodies, which have been recently identified as a potential biomarker for IBM 1.
Autoantibodies in IBM
The autoantibodies associated with IBM include:
- Anti-cN1A (cytosolic 5'-nucleotidase 1A) antibodies, which are found in approximately 30-40% of IBM patients 2, 3
- Anti-NDUFA11 autoantibodies, which have been recently identified as a potential biomarker for IBM 1
Neurological Involvement
IBM does have neurological involvement, with both myopathic and neuropathic features, including:
- Nerve involvement, which can include thickened nerves and neuropathic changes
- Neuropathic changes, though acute inflammatory demyelinating polyneuropathy is not typically considered a classic feature of IBM
Skin and Respiratory Manifestations
Regarding skin manifestations, IBM generally does not cause skin ulcerations or significant cutaneous involvement, which distinguishes it from dermatomyositis. If a patient with IBM presents with shortness of breath, this is less likely to be directly related to the IBM itself, as IBM typically does not cause significant interstitial lung disease or respiratory muscle weakness to the extent seen in other inflammatory myopathies like polymyositis or dermatomyositis. However, dysphagia (swallowing difficulty) is common in IBM and can lead to aspiration pneumonia, which might present as shortness of breath.
Management and Pathophysiology
IBM is generally resistant to conventional immunosuppressive therapies, and management focuses on physical therapy, occupational therapy, and supportive care to maintain function and quality of life. The pathophysiology of IBM is complex, involving both inflammatory and degenerative processes, with accumulation of abnormal proteins in muscle fibers, which explains why it responds poorly to immunosuppression compared to other inflammatory myopathies. The most recent and highest quality study on this topic is 1, which highlights the importance of anti-NDUFA11 autoantibodies as a potential biomarker for IBM.