039 Inhibitory effect on skin fibrosis by regulating Th17 and regulatory T cell imbalance in a systemic sclerosis mouse model and the involvement of alteration in the intestinal microbiota

There is growing evidence that Th17/regulatory T (Treg) imbalance associated with the etiology of autoimmune diseases. Heligmosomoides polygyrus (Hp) a natural intestinal parasite mice and has been shown to activate Tregs in host suppress symptoms diseases models. To evaluate involvement Th17/Treg balance pathogenesis systemic sclerosis (SSc), we investigated effect Hp-activated on bleomycin-induced SSc mouse model. Prior infection Hp inhibited skin fibrosis. CD3+ cells CD68+ macrophages induced by bleomycin were reduced Hp. Flowcytometric analysis lymph nodes showed an increase CD4+CD25+Foxp3+ decrease CD4+IL-17+Th17 due infection. These anti-fibrotic, anti-inflammatory, Th17 cell-reducing effects observed bleomycin-treated abolished depletion Tregs. results suggest increases suppresses cells, leading inhibitory Furthermore, microbiota revealed several bacteria increased Hp-infected mice. In patients, Treg activation patients severe sclerosis. alterations could be involved development progression disease. conclusion, found may SSc, proper regulation increasing new therapeutic target for SSc.