Specific strains of Streptococcus mutans, a pathogen of dental caries, in the tonsils, are associated with IgA nephropathy

Seigo Ito, Taro Misaki, Shuhei Naka, Kaoruko Wato, Yasuyuki Nagasawa, Ryota Nomura, Masatoshi Otsugu, Michiyo Matsumoto-Nakano, Kazuhiko Nakano, Hiroo Kumagai, Naoki Oshima

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Abstract

Streptococcus mutans is known to be a major causative agent of dental caries, and strains expressing the cell surface collagen-binding Cnm protein contribute to the development of several systemic diseases. A relationship between tonsillar immunity and glomerulonephritis has been recognized in IgA nephropathy (IgAN), and specific pathogens may have effects on tonsillar immunity (mucosal immunity). Here, we present findings showing a relationship between the presence of Cnm-positive S. mutans strains in the tonsils of IgAN patients and IgAN condition/pathogenesis. Analyses of tonsillar specimens obtained from patients with IgAN (n = 61) and chronic tonsillitis (controls; n = 40) showed that the Cnm protein-positive rate was significantly higher in IgAN patients. Among IgAN patients, the tonsillar Cnm-positive group (n = 15) had a significantly higher proportion of patients with high urinary protein (>1.5 g/gCr) and lower serum albumin level than the Cnm-negative group (n = 46). Additionally, Cnm protein and CD68, a common human macrophage marker, were shown to be merged in the tonsils of IgAN patients. These findings suggest that Cnm-positive S. mutans strains in the tonsils may be associated with severe IgAN.

Original languageEnglish
Article number20130
JournalScientific reports
Volume9
Issue number1
DOIs
Publication statusPublished - Dec 1 2019

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Ito, S., Misaki, T., Naka, S., Wato, K., Nagasawa, Y., Nomura, R., Otsugu, M., Matsumoto-Nakano, M., Nakano, K., Kumagai, H., & Oshima, N. (2019). Specific strains of Streptococcus mutans, a pathogen of dental caries, in the tonsils, are associated with IgA nephropathy. Scientific reports, 9(1), [20130]. https://doi.org/10.1038/s41598-019-56679-2