Fig. 2

Correlation between frequencies of Bregs and different laboratory parameters. a. No difference of CD24^hiCD38^hi Bregs frequencies was found between active and inactive JIA patients (8.07 ± 2.48% vs. 7.50 ± 1.52%, p = 0.8494). b The frequency of CD24^hiCD38^hi Bregs was significantly lower in RF-positive JIA patients than in RF-negative patients (10.81 ± 1.80% vs. 17.11 ± 1.14%, p = 0.0199). c No significant correlation was found between frequencies of CD24^hiCD38^hi Bregs and ESR (Spearman’s r = − 0.5108, p = 0.0519). d No significant correlation was found between frequencies of CD24^hiCD38^hi Bregs and IL-10 producing regulatory B cells (B10 cells) (Spearman’s r = 0.0883, p = 0.7438). e No significant correlation was found between frequency of B10 cells and ESR (Spearman’s r = − 0.2549, p = 0.3073). f No difference of levels of B10 cells was found between RF-positive and RF-negative patients (8.07 ± 2.48% vs. 7.50 ± 1.52%, p = 0.8494). Bregs, regulatory B cells; ESR, erythrocyte sediment rate; JIA, juvenile idiopathic arthritis; RF, rheumatoid factor. * p < 0.05