Comparative analysis of the tonsillar microbiota in IgA nephropathy and other glomerular diseases

Abstract

Immunoglobulin A nephropathy (IgAN) involves repeated events of gross haematuria with concurrent upper airway infections. The mucosal immune system, especially the tonsil, is considered the initial site of inflammation, although the role of the tonsillar microbiota has not been established in IgAN. In this study, we compared the tonsillar microbiota of patients with IgAN (n = 21) and other glomerular diseases (n = 36) as well as, healthy controls (n = 23) from three medical centres in Korea. The microbiota was analysed from tonsil swabs using the Illumina MiSeq system based on 16S rRNA gene. Tonsillar bacterial diversity was higher in IgAN than in other glomerular diseases, although it did not differ from that of healthy controls. Principal coordinates analysis revealed differences between the tonsillar microbiota of IgAN and both healthy and disease controls. The proportions of Rahnella, Ruminococcus_g2, and Clostridium_g21 were significantly higher in patients with IgAN than in healthy controls (corrected p < 0.05). The relative abundances of several taxa were correlated with the estimated glomerular filtration rate, blood urea nitrogen, haemoglobin, and serum albumin levels. Based on our findings, tonsillar microbiota may be associated with clinical features and possible immunologic pathogenesis of IgAN.

How will artificial intelligence and bioinformatics change our understanding of IgA Nephropathy in the next decade?

“…These taxonomic alterations were noted in IgAN patients when compared to healthy controls [26,31,32,34,36] or other nephropathy patients [32,33]. Some of the analyses also linked specific microbiota with remission rates [26,36] and clinical measurements, such as proteinuria [34], serum albumin [32,33], and inflammatory markers [34], thus highlighting the microbiome's potential as a diagnostic and prognostic marker of IgAN.…”

“…A sequencing-based technique targeting the bacterial 16S ribosomal RNA gene has been widely used to profile the taxonomic composition of the microbiome in different conditions. 16S analyses in IgAN reported alterations in the microbiome's structure in the saliva [31], tonsil swabs [32], and gut [33][34][35], while denaturing gradient gel electrophoresis showed compositional changes in tonsil tissues [36]. These taxonomic alterations were noted in IgAN patients when compared to healthy controls [26,31,32,34,36] or other nephropathy patients [32,33].…”

“…16S analyses in IgAN reported alterations in the microbiome's structure in the saliva [31], tonsil swabs [32], and gut [33][34][35], while denaturing gradient gel electrophoresis showed compositional changes in tonsil tissues [36]. These taxonomic alterations were noted in IgAN patients when compared to healthy controls [26,31,32,34,36] or other nephropathy patients [32,33]. Some of the analyses also linked specific microbiota with remission rates [26,36] and clinical measurements, such as proteinuria [34], serum albumin [32,33], and inflammatory markers [34], thus highlighting the microbiome's potential as a diagnostic and prognostic marker of IgAN.…”

Dysbiosis in the Salivary Microbiome Associated with IgA Nephropathy—‍A‍ ‍Japanese Cohort Study

“…The human microbiome is closely associated with mucosal immunity, and previous findings implicated the gut, tonsil, periodontal, and salivary microbiota in IgAN (De Angelis et al, 2014;Nagasawa et al, 2014;Piccolo et al, 2015;Watanabe et al, 2017;Cao et al, 2018;Luan et al, 2019;Dong et al, 2020;Hu et al, 2020;Park et al, 2020). However, despite Japan having the second highest incidence and frequency of IgAN (Schena and Nistor, 2018), few studies have been conducted on the IgAN-associated microbiota in a Japanese cohort.…”

“…A transgenic murine model of IgAN highlighted the essential dependence of signals from the commensal microbiota for kidney IgA deposition in the pathogenesis of IgAN ( McCarthy et al , 2011 ). Few studies have reported a change in the composition of the gut ( De Angelis et al , 2014 ; Dong et al , 2020 ; Hu et al , 2020 ), salivary ( Piccolo et al , 2015 ; Luan et al , 2019 ), periodontal ( Cao et al , 2018 ), or tonsillar ( Park et al , 2020 ) microbiota in Caucasian, Chinese, and Korean IgAN patients. However, none of these studies investigated microbiome changes in IgAN versus IBD.…”