Background The course and outcome of oligo-JIA is more or less unpredictable. So far, no internationally acceptable prognostic biomarkers, regarding the progression of oligo- to the extended disease type have been defined.

Objectives The aim of this study was to assess the immunophenotype plus cytokine profile in synovial fluid (SF) of patients (pts) with JIA and to evaluate the findings in respect to the severity of the disease course in order to define those pts who need early aggressive treatment.

Methods 73 SF samples from the knees of 57 JIA patients (F: 48, median age 11.49 yrs) were studied. 20/57 pts had oligo-persistent (O-per), 27 oligo-extended (O-ext) and 10 polyarthritis (poly). 25 age-matched children (25 SF samples) with recent traumatic knee arthritis served as controls. The SF immunophenotype and cytokine levels were assessed by flow cytometry and ELISA respectively.

Results The median CD4:CD8 T cell ratio was found to be significantly lower in 19/57 pts (24/73 samples) from all 3 JIA pt groups as compared to the controls (0.75 vs 1.55, p<0.01). Also, the median CD4:CD8 ratio was significantly lower in the O-ext disease type (0.70) as compared to O-per and poly (1.54 and 1.57 respectively p<0.01). 23/24 SF samples with a low (<0.8) ratio had a polyarticular disease course (21 O-ext, 3/10 poly). Tregs were significantly lower and Th17 significantly higher in all 3 JIA pt groups as compared to the controls (p<0.001), especially in O-ext. Cytokines IL-17, IL-23 and IL-6 were significantly higher in all JIA pt groups as compared to the controls. A positive correlation between low CD4:CD8 ratio and the disease duration as well as, values of Th17 cells, IL-17 and IL-23 levels were found regardless of the JIA subtype.

Conclusions A low ratio of CD4:CD8 T cells in combination with high levels of IL-17 and IL-23 in SF of JIA pts can predict a prolonged, polyarticular course of the disease and may be used as “the window of opportunity” for a more targeted treatment.

References

1. Hunter PJ, et al. Biologic predictors of extension of oligoarticular juvenile idiopathic arthritis as determined from synovial fluid cellular composition and gene expression. Arthritis Rheum 2010;62: 896-907.

Disclosure of Interest None declared