Safety and efficacy assessment of fecal microbiota transplantation as an adjunctive treatment for IgA nephropathy: an exploratory clinical trial.

To assess the safety and efficacy of fecal microbiota transplantation (FMT) as an adjunctive therapeutic intervention for IgA nephropathy (IgAN). Fifteen patients with IgA nephropathy were recruited based on inclusion and exclusion criteria and underwent FMT using enteric microbial capsules. Clinical indicators, intestinal microbiota and metabolomic profiles, as well as changes in serum immune cells and cytokines, were monitored before and after FMT. No severe adverse reactions were observed in the subjects. After FMT, there was a reduction in the 24-h urinary protein quantification in subjects. The relative abundances of Phocaeicola_vulgatus, Bacteroides_uniformis, Prevotella_copri, Phocaeicola_dorei, Bacteroides_ovatus, Bacteroides_xylanisolvens, Parabacteroides _distasonis, Bifidobacterium_pseudocatenulatum, Bacteroides_sp._HF-162, and Bifidobacterium_longum changed after FMT. In terms of intestinal metabolites, the levels of acylcarnitine18:0 (ACar.18:0), cotinine, N-arachidonoyl-L-serine, phosphatidylcholine (PC. (18:3e/22:6)), serotonin, and fumagillin showed significant changes. Flow cytometry analysis showed the absolute count of plasma B cells decreased in subjects, and this change correlated with alterations in the intestinal microbiota and metabolites. This study preliminarily evaluates the safety and efficacy of FMT in patients with IgAN. No significant adverse reactions were observed, and the administration of FMT alongside ACEI/ARB therapy was effective in reducing urinary protein levels in patients with IgAN, a process that may be associated with B-cell immunity.