Summary Naturally occurring CD4+ CD25 + regulatory T cells (nTreg) play a major role in controlling autoimmunity by suppressing self-reactive T cells. Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the central nervous system (CNS), where T cells play a key role in orchestrating tissue damage. While CD4 + CD25 + nTreg have been investigated in peripheral blood from MS patients, little is known about their presence and possible function within the target organ, the CNS. In order to study whether these cells are present in the cerebrospinal fluid (CSF) under pathological conditions, we have analysed the frequency of CD4 + CD25 + nTreg in peripheral blood and CSF from MS patients (n = 14), patients with other neurological disorders (OND; n = 9) and compared peripheral levels with healthy controls (n = 40). We found that the frequency of CD4 + CD25 + forkhead transcription factor 3 (FOXP3) + nTreg was significantly elevated in the CSF from MS patients (mean CSF = 4·05 Ϯ 1·54% versus mean peripheral blood = 2·93 Ϯ 0·94%) but not from patients with other neurological disorders (mean CSF = 3·78 Ϯ 1·26% versus mean peripheral blood = 3·74 Ϯ 1·4%). The frequency of nTreg in the periphery did not differ between MS patients and healthy donors; however, nTreg from MS patients showed reduced suppressive capacity.
FOXP3-expressing naturally occurring CD4+CD25high T regulatory cells (Treg) are relevant in the control of autoimmunity, and a defect in this cell population has been observed in several human autoimmune diseases. We hypothesized that altered functions of peripheral Treg cells might play a role in the immunopathogenesis of myasthenia gravis, a T cell-dependent autoimmune disease characterized by the presence of pathogenic autoantibodies specific for the nicotinic acetylcholine receptor. We report in this study a significant decrease in the in vitro suppressive function of peripheral Treg cells isolated from myasthenia patients in comparison to those from healthy donors. Interestingly, Treg cells from prednisolone-treated myasthenia gravis patients showed an improved suppressive function compared with untreated patients, suggesting that prednisolone may play a role in the control of the peripheral regulatory network. Indeed, prednisolone treatment prevents LPS-induced maturation of monocyte-derived dendritic cells by hampering the up-regulation of costimulatory molecules and by limiting secretion of IL-12 and IL-23, and enhancing IL-10. In addition, CD4+ T cells cultured in the presence of such tolerogenic dendritic cells are hyporesponsive and can suppress autologous CD4+ T cell proliferation. The results shown in this study indicate that prednisolone treatment promotes an environment that favors immune regulation rather than inflammation.
Angiogenesis in pancreatic ductal adenocarcinomas depends on the presence of angiogenic factors such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) and is thought to be stimulated by hypoxia. We tested the angiogenic potential of 9 cell lines of pancreatic ductal carcinoma origin by screening mRNA and protein expression of VEGF and bFGF and the release of VEGF into culture medium under normoxic and hypoxic (5% or 0.2% O 2 ) conditions. Angiogenic activity was determined using 2-and 3-D endothelial cell assays. Furthermore, VEGF expression and tumor vascularization were studied in human pancreatic carcinoma tissues from orthotopic xenografts and resection specimens. All cell lines expressed (mRNA, protein) and secreted VEGF, whereas bFGF was only found in 3 cell lines and was secreted into the medium in low concentrations. In addition to the dominant isoforms VEGF 121 ,VEGF 165 and VEGF 189 , 2 isoforms described recently, VEGF 145 and VEGF 183 , were detected. Severe hypoxia (0.2% O 2 ), but not moderate hypoxia (5% O 2 ) raised VEGF mRNA expression and protein secretion in 7/9 and 5/9 cell lines, respectively. Conditioned media from 7/9, 6/9, 8/9 and 7/9 cell lines stimulated endothelial cell proliferation under normoxic (24 and 48 hr) or hypoxic (24 hr, 0.2% and 48 hr 5% O 2 ) conditions, respectively. Conditioned media from 4/9 cell lines also induced capillary-like sprouting under normoxic conditions and from 6/9 under hypoxic (0.2% O 2 ) conditions. In xenografted carcinoma tissues microvessel density was found not to be increased around areas of ischemic necrosis. In resected ductal carcinomas showing tumor necrosis VEGF expression and microvessel density were only increased in 3/12 and 2/13 cases, respectively. In conclusion, in vitro most pancreatic ductal carcinomas show a distinct VEGF related angiogenic potential, as demonstrated by 2-and 3-D endothelial cell proliferation, which may be promoted by severe hypoxia. Surprisingly, perinecrotic tumor areas, which are supposed to be hypoxic, only rarely showed the expected increase in microvessel density and VEGF expression.
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