Methods: B cell phenotype was analysed based on CD19, CD24 and CD38 expression using multiparameter flow cytometry analysis and was performed on PBMC from JIA patients (n=185), age-matched healthy controls (n=37) as well as SFMC from JIA patients (n=52, n=47 of which were paired with blood samples from the same patient). This evidence concerns the gene CD38 and juvenile idiopathic arthritis.