Proteomic analyses of plasma-derived exosomes in IgG4-RD and its potential role in B

Objective: This study aimed to investigate plasma exosome profiling of IgG4-RD and its potential role in B cell differentiation and tissue damage. Methods: One hundred untreated IgG4-RD patients and 135 sex, age matched healthy controls (HCs) were enrolled in this study. A combination of liquid chromatography-tandem mass spectroscopy (LC-MS/MS) and TMT label quantitation was used to detect exosome and B cell profiling. To validate differentially expressed proteins, western blot and ELISA were performed. RT-qPCR was used to detect gene expression after exosome stimulation. Flowcytometry was used to measure B cell activation, apoptosis, differentiation and reactive oxygen species (ROS) expression. Besides, correlation analysis between differentially expressed complement protein and laboratory parameters was also performed. Results: In total, 82 proteins were upregulated and 96 proteins were downregulated in exosome of IgG4-RD patients compared with HCs.