Midazolam Inhibits IgE Production through Suppression of Class Switch Recombination

Abstract

Midazolam（MDZ）is reported to have immunomodulatory properties that affect immune cells. However, little is known about the effects of MDZ treatment on Immunoglobulin（Ig）E responses. Therefore, we examined whether MDZ is able to suppress total IgE production, followed by IgE class switch recombination（CSR）, in a mouse model. To assess the effects of MDZ on IgE-CSR, splenic B cells were cultured with LPS, IL-4 and anti-CD40 antibody in the presence or absence of MDZ for 72 h. Total-IgE, interferon-gamma（IFN-γ）responses and surface IgE-positive（sIgE+）B cells were analyzed by ELISA and flow cytometry. To confirm IgE-CSR, total RNA was isolated from splenic B cells and levels of CSR-associated molecules, such as germ-line transcript ε（εGLT）, germ-circle transcript ε（εCT）, activation-induced cytidine deaminase（AID）and inhibitor of differentiation 2（Id2） were compared. MDZ significantly decreased total IgE production and numbers of sIgE+ B cells. Significantly reduced levels of both εGLT- and εCT-specific mRNA were detected in MDZ-treated B cells. In contrast, Id2-specific mRNA transcript, which is a negative regulator for Ig-CSR, was increased on MDZ-treated B cells. Furthermore, MDZ-treated B cell significantly increased IFN-γ production and IFN-γRα expression. These results suggest that MDZ inhibits εGLT and εCT expression, and IgE synthesis via induction of IFN-γ production. MDZ may be useful for preventing IgE-mediated allergic diseases.