[Quantity and function of regulatory B cells of the patients with immune thrombocytopenia]

To explore the quantity and function of regulatory B cells (Bregs) in peripheral blood (PB) of the patients with immune thrombocytopenia (ITP).

A total of 67 ITP patients (35 patients were newly diagnosed, 32 patients were in remission) were collected from November 2013 to October 2014 in our hospital. And 30 normal controls were enrolled in this study. Their PB Bregs (CD19⁺CD24(hi)CD38(hi) cells) and related molecules interleukin-10 (IL-10) in Bregs were detected by flow cytometry (FCM). Correlation between Bregs and clinical parameters of ITP patients was analysed.

The percentage of Bregs in CD19⁺ cells of newly diagnosed ITP patients (3.09% ± 2.57%) was significantly lower than that of remitted ITP patients (7.78% ± 6.59%, P = 0.002) and controls (5.42% ± 3.31%, P = 0.003). The percentage of IL-10⁺ cells in Bregs of newly diagnosed ITP patients (32.30% ± 12.71%) was significantly lower than that of remitted ITP patients (71.73% ± 18.08%, P = 0.000) and controls (51.01% ± 17.08%, P = 0.026). And the percentage of IL-10⁺ cells in Bregs of remitted ITP patients was significantly higher than that of controls (P = 0.026). The level of Bregs of newly diagnosed ITP patients had significantly positive correlation with myeloid dendritic cells (mDC) (r = 0.644, P = 0.003) and PB platelet count (r = 0.327, P = 0.006).

Bregs involved in the pathogenesis of ITP might be a potential therapeutic target of this disease.