Defective Circulating Regulatory B Cells in Patients with Dilated Cardiomyopathy

Abstract

Background/Aims: Newly identified IL-10-producing regulatory B cells (Bregs) have been shown to play an important role in the suppression of immune responses. Chronic immune activation participates in the pathogenesis of dilated cardiomyopathy (DCM) but whether Bregs are involved in its development remains unclear. We aimed to investigate the circulating frequency and function of Bregs in DCM. Methods: In total, 35 DCM patients (20 men and 15 women) and 44 healthy controls (23 men and 21 women) were included in the experiment, and the frequency of Bregs was detected using flow cytometry. Results: According to our results, the frequency of circulating IL-10-producing Bregs was significantly lower in DCM patients compared with healthy controls. Furthermore, the CD24^hiCD27⁺ B cell subset in which IL-10-producing Bregs were mainly enriched from DCM patients showed impaired IL-10 expression and a decreased ability to suppress the TNF-α production of CD4⁺CD25^- Tconv cells and to maintain Tregs differentiation. Correlation analysis showed that the frequency of IL-10-producing Bregs and the suppressive function of CD24^hiCD27⁺ B cells were positively correlated with left ventricular ejection fraction and negatively correlated with NT-proBNP in DCM patients. Conclusions: In conclusion, the reduced frequency and impaired functions suggest a potential role of Bregs in the development of DCM.