The Immunodeficiency Profile of Lymphocytes in the Patient with Moesin Gene Mutation During Different Infection.

PURPOSE: The Ezrin-Radixin-Moesin (ERM) family member moesin (MSN) plays a crucial role in reversibly linking F-actin to the cell membrane. Patients carrying MSN gene mutations consistently exhibit immunodeficiencies. However, due to the scarce number of reported cases worldwide, the mechanism by which MSN mutation leads to immune function defects remains unclear. This study aims to profile the immunological features in MSN mutant patients elaborately. METHODS: In this article, we present a case study of a patient with c.511 C > T, p.Arg171Trp (p.R171W) mutation on the MSN gene. We analyzed abnormalities in peripheral immune cell subsets by quantitative analysis, morphological examination, and functional molecule assessment during various infection states. Using total internal reflection fluorescence microscopy (TIRFm), we visualized BCR clusters and F-actin dynamics in B cells, revealing valuable insights into B cell activation and the link between F-actin aggregation and BCR signaling in MSN mutant patients. RESULTS: The results suggest that the MSN c.511 C > T, p.Arg171Trp (p.R171W) mutation affects the proliferation, differentiation, metabolism, and adhesion functions in peripheral immune cells, as well as the maturation process in bone marrow cells. Additionally, we elucidate the impact of MSN mutation on B cell and T cell metabolism and propose a potential diagnostic indicator for patients with MSN gene mutations. CONCLUSION: Our findings support the diagnosis of primary immunodeficiency and provide detailed insights into changes occurring in immune cells, especially B cells. Overall, our study adds to the diagnosis and pathogenesis of X-linked moesin-associated immunodeficiency (X-MAID).