Lupus mesenteric vasculitis (LMV) is a unique clinical entity found in patients who present with gastrointestinal manifestations of systemic lupus erythematosus, and is the main cause of acute abdominal pain in these patients. LMV usually presents as acute abdominal pain with sudden onset, severe intensity and diffuse localization. Other causes of abdominal pain, such as acute gastroenteritis, peptic ulcers, acute pancreatitis, peritonitis, and other reasons for abdominal surgery should be ruled out. Prompt and accurate diagnosis of LMV is critical to ensure implementation of appropriate immunosuppressive therapy and avoidance of unnecessary surgical intervention. The pathology of LMV comprises immune-complex deposition and complement activation, with subsequent submucosal edema, leukocytoclastic vasculitis and thrombus formation; most of these changes are confined to small mesenteric vessels. Abdominal CT is the most useful tool for diagnosing LMV, which is characterized by the presence of target signs, comb signs, and other associated findings. The presence of autoantibodies against phospholipids and endothelial cells might provide information about the likelihood of recurrence of LMV. Immediate, high-dose, intravenous steroid therapy can lead to a favorable outcome and prevent serious complications such as bowel ischemia, necrosis and perforation.

Myeloid-derived suppressor cells (MDSCs) are heterogenous populations of immature myeloid progenitor cells with immunoregulatory function. MDSCs play critical roles in controlling the processes of autoimmunity but their roles in rheumatoid arthritis (RA) are controversial. The present study was undertaken to investigate whether MDSCs have therapeutic impact in mice with collagen-induced arthritis (CIA), an animal model of RA. We also examined the mechanisms underlying the anti-arthritic effect of MDSCs. In vitro treatment with MDSCs repressed IL-17 but increased FOXP3 in CD4+ T cells in mice. In vivo infusion of MDSCs markedly ameliorated inflammatory arthritis. Th17 cells and Th1 cells were decreased while Tregs were increased in the spleens of MDSCs-treated mice. MDSCs profoundly inhibited T cell proliferation. Addition of anti-IL-10 almost completely blocked the anti-proliferative effects of MDSCs on T cells. Anti-IL-10 blocked the expansion of Tregs by MDSCs. However, infusion of MDSCs from IL-10 KO mice failed to suppress inflammatory arthritis. MDSCs could reciprocally regulate Th17/Treg cells and suppress CIA via IL-10, suggesting that MDSCs might be a promising therapeutic strategy for T cell mediated autoimmune diseases including RA.

Fibroblast-like synoviocytes (FLSs) are a major cell population of the pannus that invades cartilage and bone in rheumatoid arthritis (RA). FLS resistance to apoptosis is a major characteristic of RA. The aims of this study were to investigate the effects of interleukin-17 (IL-17) and IL-17-producing T helper (Th17) cells on resistance to apoptosis in FLSs from RA patients (RA FLSs) and their roles in mitochondrial dysfunction and autophagy. Mitochondrial function was assessed in RA FLSs and FLSs from osteoarthritis patients (OA FLSs). FLSs were treated with IL-17 and their morphological features, respiratory level and mitochondrial gene expression were measured. The effects of IL-17 and Th17 cells on the relationship between autophagy and apoptosis were evaluated by measuring the expression of apoptosis-related genes using sodium nitroprusside or 3-methyladenine. The mitochondria of FLSs isolated from RA and osteoarthritis patients displayed different morphological and physiological features. RA FLSs exhibited greater autophagosome formation and greater dysfunction of mitochondrial respiration compared with OA FLSs. IL-17 induced mitochondrial dysfunction and autophagosome formation in RA FLSs, suggesting that they were resistant to apoptosis. Autophagy-related antiapoptosis induced by IL-17 was restored by inhibition of autophagy, suggesting a relationship between mitochondrial dysfunction and cell survival in RA FLSs. Th17 cells and IL-17 increased autophagy of RA FLSs by causing mitochondrial dysfunction. Our findings suggest that, in RA, interactions between RA FLSs and Th17 cells may be involved in the tumorous growth of FLSs and the formation of pannus in joints.

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