Migration Inhibition Factor Secreted by Peripheral Blood Memory B Cells Binding to CD74-CD44 Receptor Complex Drives Macrophage Behavior in Alzheimer's Disease.

Dysregulation of the peripheral immune system is be involved in the neuroinflammation in Alzheimer disease (AD) and accelerate the disease progression. The contribution of immune cells, particularly B cells, to AD pathogenesis has gained attention in recent research. In this study, we investigated the role of Peripheral Blood Memory B cells (PBMBs) and their secreted Migration Inhibition Factor (MIF) in driving macrophage behavior in AD based on the scRNA-seq technique, immunofluorescence and flow cytometry. We discovered that MIF binds to the CD74-CD44 receptor complex on macrophages, influencing their behavior. The dysregulated macrophage response hampers the clearance of amyloid-beta (Aβ) plaques, exacerbating AD pathology. Targeting the MIF-CD74-CD44 signal pathway may hold therapeutic potential in modulating macrophage activity and mitigating neuroinflammation in AD. This study provides a further understanding of peripheral immune cells dysregulated in AD.