New thoughts on the intestinal microbiome-B cell-IgA axis and therapies in IgA nephropathy.

IgA nephropathy (IgAN), as the most common chronic glomerulonephritis worldwide, is often triggered by mucosal infections and follows a chronic progression, with the majority of patients ultimately progressing to end-stage renal disease (ESRD) during their lifetimes. Since the mystery of its complete pathogenesis has not been fully solved, the resulting lack of effective early diagnosis and treatment greatly affects the prognosis of patients. Given the well-defined pathological feature of IgA deposition in the mesangial region, the source and role of pathogenic IgA has been focused on. Starting from the microbiology and immunity of the gut, we systematically review both the physiological and the pathological process of microbiome-B cell-IgA axis, from microbial-induced IgA production to the role of IgA in the intestinal immune milieu, and ultimately end up with the various aspects of microbiome-B cell-IgA axis in the pathogenesis of IgAN as well as the corresponding therapeutic initiatives available. Our retrospective review helps researchers to systematically understand the complex role between intestinal flora dysbiosis and pathogenic IgA in IgAN. This understanding provides a foundation for in-depth explorations to uncover more detailed pathogenic mechanisms and to develop more precise and effective diagnostic and therapeutic approaches.