Anti-mitochondrial M2 antibody links to cardiac involvement and immune-mediated inflammatory myopathy-like pathology in myositis
Authors' conclusion
AMA-M2 positivity defines an IIM subgroup with significant cardiac involvement and an immune-mediated inflammatory muscle histology, but not necessarily worse long-term survival.
Study context
- Population
- Idiopathic inflammatory myopathies (IIM) patients hospitalized at Peking Union Medical College Hospital, 2008–2020
- Participants
- 987 patients
- Exposure
- AMA-M2-positive vs AMA-M2-negative IIM
- AMA-M2-positiven = 55
- Outcome
- Cardiac involvement throughout disease course
Methodological detailssingle-centre, registry-based (Prospective Registry Of MyositIS (PROMIS)), multivariate Cox regression
- Single-centre
- Registry-based (PROMIS)
- Multivariate Cox regression
Main finding
As reported in the abstract
| Group | Value | Arrhythmias | HF | Pulmonary hypertension |
|---|---|---|---|---|
| AMA-M2-positive | 60% | 56% | 44% | 31% |
| AMA-M2-negative | 12.9% |
Value
AMA-M2-positive60%
AMA-M2-negative12.9%
Arrhythmias
AMA-M2-positive56%
AMA-M2-negative— not stated in the abstract
HF
AMA-M2-positive44%
AMA-M2-negative— not stated in the abstract
Pulmonary hypertension
AMA-M2-positive31%
AMA-M2-negative— not stated in the abstract
- AMA-M2-positive vs AMA-M2-negative: P < 0.001
- AMA-M2 positivity as independent risk factor for cardiac involvement (multivariate Cox), HR
- 3.156, P < 0.001
Observational data: associations, not effects.
Further findings
PM rate
P < 0.001
Long-term survival
P = 0.86
| Outcome | AMA-M2-positive | AMA-M2-negative | P value |
|---|---|---|---|
| Baseline gamma-glutamyl transferase | 78.0 | 35.0 | P < 0.001 |
| Baseline alkaline phosphatase | 85.0 | 64.0 | P < 0.001 |
Biopsy findings
- Some muscle biopsies showed features consistent with immune-mediated necrotizing myopathy; cardiac biopsies showed structural degeneration with minimal inflammation; liver biopsies confirmed early-stage primary biliary cholangitis (PBC)
Original publication
Anti-mitochondrial M2 antibody links to cardiac involvement and immune-mediated inflammatory myopathy-like pathology in myositis. Rheumatology (Oxford). Published 2 January 2026. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →