The pattern of MHC class I expression in muscle biopsies from patients with myositis and other neuromuscular disorders
Authors' conclusion
MHC-I immunostaining was useful to distinguish IIMs from non-inflammatory myopathies or neurogenic disorders.
Study context
- Population
- Diagnostic muscle biopsies processed at the Johns Hopkins Neuromuscular Pathology Laboratory, August 2013 to January 2017
- Participants
- 357 muscle biopsies
- Exposure
- MHC-I immunostaining across normal biopsies, idiopathic inflammatory myopathies (IIMs), non-inflammatory myopathies and neurogenic disorders
- Normaln = 31reference
- IIMsn = 170
- Non-inflammatory myopathiesn = 60
- Neurogenic disordersn = 96
- Outcome
- Prevalence and patterns of abnormal MHC-I immunostaining
Methodological detailsretrospective, single-centre
- Retrospective
- Single-centre
Main finding
As reported in the abstract
Abnormal MHC-I immunostaining
Observational data: associations, not effects.
Further findings
| Outcome | Values |
|---|---|
| Diagnostic accuracy of abnormal MHC-I immunostaining for IIMs | Abnormal MHC-I immunostaining sensitivity 0.95 · specificity 0.82 |
| Perifascicular MHC-I pattern in DM biopsies without perifascicular atrophy (n = 18) | DM without perifascicular atrophy 50% |
MHC-I staining patterns
- Focal pattern associated with immune-mediated necrotizing myopathy (IMNM)
- Global pattern more prevalent in sporadic IBM (sIBM)
- Perifascicular pattern significantly more common in DM
- Sarcoplasmic upregulation more common than sarcolemmal staining across all groups
Original publication
The pattern of MHC class I expression in muscle biopsies from patients with myositis and other neuromuscular disorders. Rheumatology (Oxford). Published 27 January 2023. doi:10.
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