A Study of Probiotics in IgA Nephropathy

IgA nephropathy (IgAN) occurs when a specific form of the IgA antibody lodges on the kidneys and causes damage, which may lead to kidney failure. This form of IgA is likely to come from the gut and the upper airways. Recent studies have shown that the bacteria that live in these areas may be different in IgAN. We think that the interaction between these and the immune system triggers production of the IgA that leads to kidney damage. We will examine these bacteria in detail, and test whether a probiotic can alter this favorably, and reduce harmful forms of IgA production in IgAN.

The purpose of this proposal is to conduct a proof of concept study, to test the hypothesis that dysbiosis of the gut microbiota plays a critical role in the development of IgAN. Objectives are firstly, to characterise the gut microbiome, and faecal, plasma and urine metabolome, in relation to biomarkers of mucosal immunity and glomerular disease in patients with IgAN. Secondly, Investigators will test whether a multi-strain probiotic (Bio-Kult Advanced) produces a modulatory effect on these indices. The probiotic has been selected with our industry collaborator Protexin, based on previous studies demonstrating reduced faecal microbial diversity in patients with progressive IgAN, compared to those with non-progressive IgAN and healthy subjects. This study will further our understanding of the interplay between the gut microbiome, metabolome, and mucosal immune system in IgAN. Investigators will generate important pilot data, to inform the design of a longer-term randomised clinical trial of probiotics in IgAN, and to identify potential plasma biomarkers to highlight those at risk of progressive disease, and those who may respond to treatments targeted to the gut.