human gut metagenome Metagenome

Multiple associations between the gut microbiota and the host immunity have been involved in many immune-mediated diseases. The pathogenesis of immunoglobulin A nephropathy (IgAN) and membranous nephropathy (MN) is characterized by immune dysregulation, which is possibly linked to gut dysbiosis. However, the relationship between the gut microbiota and the two glomerular diseases has not been adequately studied. This study used 16S rRNA gene amplicon sequencing to investigate the bacterial communities of 44 patients with kidney biopsy-proven IgAN, 40 patients with kidney biopsy-proven MN, and 30 matched healthy controls (HC). Compared with healthy controls, abundances of Escherichia-Shigella and Defluviitaleaceae_incertae_sedis were significantly higher in IgAN, whereas lower abundances were observed for Roseburia, Lachnospiraceae_unclassified, Clostridium_sensu_stricto_1 and Fusobacterium. Meanwhile, Escherichia-Shigella, Peptostreptococcaceae_incertae_sedis, Streptococcus and Enterobacteriaceae_unclassified were increased, while Lachnospira, Lachnospiraceae_unclassified, Clostridium_sensu_stricto_1 and Veillonella were decreased in MN. Compared with MN, genera Megasphaera and Bilophila were increased, Megamonas, Veillonella, Klebsiella and Streptococcus were decreased in patients with IgAN. Correlations between the fecal microbiota and clinical biomarkers were evaluated by Spearman correlation analysis. In IgAN group, Prevotella showed positive correlation, while Klebsiella, Citrobacter, and Fusobacterium showed negative correlations with the level of the serum albumin. Positive correlation also existed between Bilophila and Crescents in the Oxford classification of IgAN. In MN group, Bacteroides and Klebsiella showed positive correlation with the MN stage, while Akkermansia showed negative correlations with the IgG4 deposition in the subepithelialby immunofluorescence. The results indicated that the human gut microbiota of patients with IgAN and MN were different from that of HC. Some taxa were associated with clinical parameters, which were risk factors for kidney prognosis. These taxa may potentially contribute to the pathogenesis and specific biomarkers of IgAN and MN.