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Determing an “autoimmune” phenotype in systemic JIA

Background

Data from research, clinics and response to treatment point out to an autoinflammatory pathogenesis in Systemic onset Juvenile Idiopathic Arthritis (SoJIA). However a subgroup of patients present with c hronic a ctive course of disease, destructive p olyarthritis and production of a utoantibodies (CAPA-subtype) not responsive to anti IL-1 treatment.

Aim

Determine phenotypic characteristics of the CAPA-subtype of SoJIA.

Methods

Retrospective analysis in a cohort of 35 SoJIA patients well characterized according clinical course and ANA, Rheumatic factor and ANCA.

Results

Autoantibodies have been found in 25,7% of the patients, with ANA being the most frequent auto-AK (table 1). There was a significant difference according the age of onset. Moreover females and carditis have been observed more frequently in the AK-pos. group.

SoJIA-Patients 35
Observation (month) mean 69 (range 1-262)
  n % n %
Autoantibodies pos neg
  9 25,7 26 74,3
ANA 6 17,1   
RF 2 5,7   
ANCA 3 8,6   
  percentage for each group
male 3 33,3 11 42,3
female 6 66,6 15 57,7
onset age (years) 6,03   3,54  
relapses 4   3,6  
joints at onset 2,1   3,1  
joints when AK pos 7    
MAS 1   1  
Carditis 6 66,7 13 50
SAA 2 of 4   8 of 12  
Amyloidosis 1   1  

Conclusion

There is evidence for an autoimmune course of disease in SoJIA in a subset of patients with chronic polyarthritis but without relapses of autoinflammation. These patients probably will need a switch in treatment to prevent further joint destruction.

Acknowledgement

supported by the BMBF (AID-Net 01GM0907)

Author information

Correspondence to JP Haas.

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Keywords

  • Public Health
  • Arthritis
  • Retrospective Analysis
  • Juvenile Idiopathic Arthritis
  • Phenotypic Characteristic