Double Negative B cells are decreased in patients with Idiopathic Inflammatory Myopathies.

Abstract

Abstract Background: Idiopathic inflammatory myopathies (IIM) are systemic autoimmune diseases characterized by skeletal muscle inflammation, frequently accompanied by extra muscular features associated with specific autoantibodies. The detailed pathogenesis of IIM remains unclear, but evidence suggests autoreactive B cells may play an essential role in this process. However, little is known about changes in peripheral blood B cell subsets in adult IIM patients. Objective: This study aims to determine the frequency of B cell subsets among patients with IIM and their clinical correlation with disease activity. Methods: Using a multiparametric flow cytometric approach, we determined the frequencies of B cell subsets in a cohort of 36 patients with IIM and correlated their values with clinical and laboratory data. Results: DN B cells (CD27 −IgD −), which represent an atypical B cell subset associated with various autoimmune diseases, showed a significant decrease in frequencies and a correlation with the MMT8 score. Within the DN subset, the DN1 subpopulation (CD21 +CD11c −) showed a significant decrease compared to the control group. There was also a significant decrease in the memory B cell subpopulation (CD27 +CD38 −) and the non-classic memory B cell subpopulation (CD27 −CD38 −CD24 +). A significant increase in naive B cells (CD27 −IgD +) was observed. However, none of the previously described subpopulations correlated with clinical features. Conclusion: This study demonstrated a decrease in frequencies in the double negative B cell subset in adult IIM patients and showed a correlation with clinical features, which suggests that these B cells could be related to disease activity. UNAM-DGAPA-PAPIIT IN212122