Autoantibodies Recognizing Specificity Protein 4 Co‐occur With Anti–Transcription Intermediary Factor 1 and Are Associated With Distinct Clinical Features and Immunogenetic Risk Factors in Juvenile Myositis
Authors' conclusion
Anti-Sp4 autoantibodies were found in patients with juvenile-onset IIM, predominantly those with coexisting anti-TIF1 autoantibodies. Patients with anti-Sp4 autoantibodies represent a phenotypic subset of anti-TIF1 autoantibody-positive myositis characterized by frequent Raynaud's phenomenon and less pronounced muscle involvement, similar to adults with these autoantibodies.
Study context
- Population
- Patients with juvenile-onset idiopathic inflammatory myopathies (IIM) in a cross-sectional cohort and healthy controlsplus 91 healthy controls
- Participants
- 336 patients
- Exposure
- Juvenile myositis with vs without anti-Sp4 autoantibodies
- Anti-Sp4+n = 23
- Healthy controlsn = 91
- Outcome
- Prevalence of anti-Sp4 autoantibodies and associated clinical features
Methodological detailsELISA screening
- ELISA screening
Main finding
As reported in the abstract
Anti-Sp4 autoantibody prevalence (ELISA)
Juvenile myositis
7%
23 events
Observational data: associations, not effects.
Further findings
| Outcome | Anti-Sp4+ | Anti-Sp4− | P value |
|---|---|---|---|
| Anti-TIF1 autoantibody positivityAnti-Sp4+ vs Anti-Sp4− | 91% | 30% | P < 0.001 |
| RP (anti-TIF1+ subgroup)Anti-Sp4+ vs Anti-Sp4− | 38% | 2% | P < 0.001 |
| Wheelchair requirement | 0 events | — not stated in the abstract |
— not stated in the abstract
Peak aspartate aminotransferase (anti-TIF1+ subgroup)
- Significantly lower with anti-Sp4 autoantibodies
HLA alleles (White patients)
- DQA1*04 and DRB1*08 associated with anti-Sp4 autoantibodies
Original publication
Autoantibodies Recognizing Specificity Protein 4 Co‐occur With Anti–Transcription Intermediary Factor 1 and Are Associated With Distinct Clinical Features and Immunogenetic Risk Factors in Juvenile Myositis. Arthritis Rheumatol. Published 19 July 2023. doi:10.
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