The Abnormal Distribution of Peripheral B1 Cells and Transition B Cells in Patients with Idiopathic Dilated Cardiomyopathy

Background: The aberrant distribution of peripheral B cell subsets is associated with the pathogenesis of a variety of inflammatory and autoimmune diseases. However, the distribution of peripheral B cell subsets in patients with idiopathic dilated cardiomyopathy (DCM) has yet to elucidated. Methods: Twenty-seven idiopathic DCM patients (DCM group), 18 heart failure controls (HF group) and 21 healthy individuals (HC group) were included in this study. Peripheral B cell subsets were analyzed by multi-color flow cytometry. Level of plasma β1 cholinergic receptor (β1-AR) autoantibody was assayed by ELISA. Additionally, clinical features were also collected. Results: Compared with HF and HC groups, the percentage of B1 cells were significantly decreased, whereas the percentage of transitional B cells (Tr) were significantly increased in DCM group. Notably, the percentage of B1 cells was significantly lower in patients with β1-AR autoantibody positive DCM compared with β1-AR autoantibody negative patients. Correlation analysis showed that the percentage of B1 cells was negatively correlated with N-terminal pro-brain natriuretic peptide (NT-proBNP) and positively correlated with left ventricular ejection fraction (LVEF) in patients with DCM. Conclusions: The study showed that B1 cells in peripheral blood of patients with idiopathic DCM were abnormally decreased, especially in those β1-AR autoantibody positive patients, while Tr cells are significantly increased, indicating that B1 cells and Tr cells may be implicated in the pathogenesis of idiopathic DCM.