Oligoarticular juvenile idiopathic arthritis (oJIA) is the most frequent form of chronic arthritis in children; the clinical course is extremely variable. In this study we have characterized by flow cytometry synovial B and T cells subsets in patients with oJIA in order to identify any parameters that could predict a more aggressive course of disease.
B and T cells from synovial fluid (SF) of 39 patients with oJIA were characterized by flow cytometry. In 22 patients SF was analysed at the onset of the disease (GroupA), in 17 SF was analysed at articular relapse (Group B). All patients in Group A were followed up for at least for 2 years after SF analysis: 13 patients relapsed during the follow-up period.
Comparison of SF from Group A and Group B demonstrated an activated phenotype in relapsed patients, with higher Switched Memory B cells (58.53 vs 36.07% of CD19+, P-value 0.004) and lower Naïve B cells (8.53 vs 25.9 of CD19+, P-value 0.002) in Group B. Furthermore, patients from Group A who did not relapse showed lower percentages of synovial DNT (2.38 vs 1.50% of CD3 + TCRalpha/beta+, P-value 0.025) and γδ T cells (19.1 vs 15.0% of CD3+ cells, P-value 0.004) at the onset, if compared with other Group A patients.
In oJIA relapse SF present an activated B phenotype. Patients at disease onset with DNTs <1.8% and/or γδ T cells <16% of CD3+ in synovial fluid have longer free-disease survival. © 2017 International Clinical Cytometry Society.