Minimal Variations of Oral Virome and Microbiome in Human IgA Deficiency

Abstract Bakcground Immunoglobulin A (IgA) is the dominant antibody found in our mucosal secretions and plays an important role in the protection and homeostatic regulation of intestinal, respiratory and urogenital epithelia by `recognizing´and shapping our human commensal microbiome. Paradoxically, yet selective IgA-deficiency in humans and animal models is often described as asymptomatic and only a few microbiome studies are available, only focused on the mice and human gut microbiome. Results Here, we broad the view an address the oral microbiome employing a more holistic view integrating in our study for the first time not only microbes but also the frequently neglected commensal viruses of our human virome and measured the impact of IgA deficiency on our microbial and viral communities. Unexpectedly, data from fine 16S rRNA gene profiling and virome and metagenome analysis in human IgA deficiency indicate minimal changes in microbiome and virome composition compared to healthy control group and point out to a rather functional, resilient oral commensal viruses and microbes. However, a significant depletion (2-fold) of number of bacterial cells (p-value <0.01) and virus-like particles (VLPs) was observed in IgA-deficiency. Conclusions Our results challenge the view of an irreplaceable IgA role for regulating the composition and function of our commensal microbiota and pose the question whether other “ back-up ” Ig-independent mechanisms dicussed here might exist for maintaining a functional commensal microbiome.