Association of anti-HMGCR antibodies of the IgM isotype with refractory immune-mediated necrotizing myopathy
Authors' conclusion
In anti-HMGCR IgG-positive IMNM patients, the levels of anti-HMGCR IgG are associated with disease activity, and anti-HMGCR IgM is associated with refractory outcome and poor prognosis.
Study context
- Population
- Immune-mediated necrotizing myopathy (IMNM) patients positive for anti-HMGCR IgG at baseline123 serum samples
- Participants
- 71 participants
- Exposure
- Anti-HMGCR IgM positive vs anti-HMGCR IgM negative
- Outcome
- Association of anti-HMGCR isotypes (IgG, IgA, IgM) with clinical features and prognosis (disease activity by MMT8, PGA VAS, muscle VAS)
Methodological detailslongitudinal analysis, consecutive serum samples
- Longitudinal analysis
- Consecutive serum samples
Main finding
As reported in the abstract
Polycyclic course, IgM positive vs negative
40% vs. 25%
Chronic continuous course, IgM positive vs negative
46.7% vs. 20.5%
Observational data: associations, not effects.
Further findings
Neck weakness
P = 0.031
- Age of onset (lower in IgM positive)
- P = 0.006
Baseline anti-HMGCR IgG levels vs disease activity (correlation)
- Physician's Global Assessment (PGA) visual analog scale (VAS): r = 0.24; p = 0.04
- Muscle VAS: r = 0.32; p < 0.01
- MMT8: r=−0.24; p = 0.04
Baseline anti-HMGCR IgM levels vs disease activity (positive correlation)
- PGA VAS: r = 0.27, p = 0.02
- Muscle VAS: r = 0.24, p = 0.04
Longitudinal: changes in anti-HMGCR IgG levels vs changes in disease activity · follow-up
- PGA VAS: β = 3.830; p < 0.0001
- Muscle VAS: β = 2.893; p < 0.0001
- MMT8: β=−19.368; p < 0.0001
- Creatine kinase (CK) levels: β = 3900.05, p < 0.0001
Anti-HMGCR IgM vs IgA levels
- Baseline correlation (weak): r = 0.33, p < 0.01
- Changes during follow-up: β = 0.885; p < 0.0001
Parts of this Brief are withheld: the automatic checks could not confirm them against the abstract.
Original publication
Composed by AI from the published abstract and checked against it. How Briefs are made →