RESUMO
Salivary gland epithelial cells (SGECs) have been implicated in the pathogenesis of Sjögren's syndrome due to aberrant antigen-presentation function. This study examined the hypothesis that oral dysbiosis modulates the antigen-presentation function of SGECs, which regulates CD4 T cell proliferation in primary Sjögren's syndrome (pSS). Saliva samples from 8 pSS patients and 16 healthy subjects were analyzed for bacterial 16S ribosomal DNA. As a result, 39 differentially abundant taxa were identified. Among them, the phylum Proteobacteria comprised 21 taxa, and this phylum was mostly enriched in the healthy controls. The proteobacterium Haemophilus parainfluenzae was enriched in the healthy controls, with the greatest effect size at the species level. Treatment of A253 cells in vitro with H. parainfluenzae upregulated PD-L1 expression, and H. parainfluenzae-pretreated A253 cells suppressed CD4 T cell proliferation. The suppression was partially reversed by PD-L1 blockade. Among low-grade xerostomia patients, salivary abundance of H. parainfluenzae decreased in pSS patients compared to that in non-pSS sicca patients. Our findings suggest that H. parainfluenzae may be an immunomodulatory commensal bacterium in pSS.
Assuntos
Disbiose/diagnóstico , Haemophilus parainfluenzae/imunologia , RNA Ribossômico 16S/genética , Saliva/microbiologia , Glândulas Salivares/citologia , Análise de Sequência de DNA/métodos , Síndrome de Sjogren/microbiologia , Idoso , Apresentação de Antígeno , Linfócitos T CD4-Positivos/metabolismo , Estudos de Casos e Controles , Linhagem Celular , Proliferação de Células , DNA Bacteriano/genética , DNA Ribossômico/genética , Células Epiteliais/citologia , Células Epiteliais/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Filogenia , Glândulas Salivares/imunologia , Glândulas Salivares/microbiologia , Síndrome de Sjogren/imunologiaRESUMO
IgA nephropathy (IgAN), the most common form of primary glomerulonephritis, is recognized as a disease that often becomes worse during acute tonsillitis. Although many reports have shown that tonsillectomy is an effective treatment for IgAN patients, the immunological evidence has not yet been investigated fully. In this study, we compared the expression of T cell receptor (TCR) V beta families in tonsillar T cells of IgAN patients to those of non-IgAN patients. The reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometric analyses showed that the TCR V beta 6 was used more frequently in tonsillar T cells of IgAN patients than in those of non-IgAN patients (P < 0.01 each). Similarly, the proportions of TCR V beta 6-positive cells in peripheral blood T cells were significantly higher in IgAN patients than in non-IgAN patients (P < 0.05). After tonsillectomy, the proportions decreased in IgAN patients (P < 0.05), but did not in non-IgAN patients. Furthermore, in vitro stimulation with Haemophilus parainfluenzae antigen, which is reported to deposit in the glomerular mesangium of IgAN, enhanced expression of TCR V beta 6 in tonsillar T cells from both IgAN and non-IgAN patients. These results suggest that TCR V beta 6-positive tonsillar T cells might be activated by H. parainfluenzae, move into the kidney through blood circulation and induce glomerulonephritis.
