IL-13Rα2-bearing, type II NKT cells reactive to sulfatide self-antigen populate the mucosa of ulcerative colitis.

OBJECTIVE: Previous studies have shown that ulcerative colitis (UC) is associated with the presence of lamina propria non-invariant (Type II) NKT cells producing IL-13 and mediating epithelial cell cytotoxicity. Here we sought to define the antigen(s) stimulating the NKT cells and to quantitate these cells in the UC lamina propria. DESIGN: Detection of Type II NKT cells in UC lamina propria mononuclear cells (LPMC) with lyso-sulfatide loaded tetramer and quantum dot-based flow cytometry and staining. Culture of UC LPMCs with lyso-sulfatide glycolipid to determine sulfatide induction of epithelial cell cytotoxicity, IL-13 production and IL-13Rα2 expression. Blinded quantum dot-based phenotypic analysis to assess UC LPMC expression of IL-13Rα2, CD161 and IL-13. RESULTS: Approximately 36% of UC LPMC were lyso-sulfatide tetramer positive, whereas few, if any, control LPMCs were positive. When tested, the positive cells were also CD3 and IL-13Rα2 positive. Culture of UC LPMC with lyso-sulfatide glycolipid showed that sulfatide stimulates UC LPMC production of IL-13 and induces UC CD161 LPMC-mediated cytotoxicity of activated epithelial cells; additionally, lyso-sulfatide induces enhanced expression of IL-13Rα2. Finally, blinded phenotypic analysis of UC LP MC using multicolour quantum dot-staining technology showed that approximately 60% of the LPMC bear both IL-13Rα2 and CD161 and most of these cells also produce IL-13. CONCLUSIONS: These studies show that UC lamina propria is replete with Type II NKT cells responsive to lyso-sulfatide glycolipid and bearing IL-13Rα2. Since lyso-sulfatide is a self-antigen, these data suggest that an autoimmune response is involved in UC pathogenesis.

Can access to urban networks promote urban development? Evidence from the Yangtze River Delta region of China.

The regional networking strategy is widely implemented in China as a normative policy aimed at fostering cohesion and enhancing competitiveness. However, the empirical basis for this strategy remains relatively weak due to limitations in measurement methods and data availability. This paper establishes the urban networks by the enterprise investment data, and then accurately measures the network's external effects of each city by the method of MGWR model. The results show that: (1) Regional networking plays a significant role in urban development, although it is not the dominant factor. (2) The benefits of network connections may vary depending on the location and level of cities. (3) The major cities assume a pivotal role in the urban network. Based upon the aforementioned research conclusions, this paper presents strategic measures to enhance the network's external impacts, aiming to offer insights for other regions in formulating regional development strategies and establishing regional urban networks.

Nodular regenerative hyperplasia in common variable immunodeficiency.

PURPOSE: Patients with Common Variable Immunodeficiency (CVID) are subject to the development of a liver disease syndrome known as nodular regenerative hyperplasia (NRH). The purpose of this study was to define the characteristics and course of this complication of CVID. METHODS: CVID patients were evaluated by retrospective and prospective clinical course review. Liver biopsy specimens were evaluated for evidence of NRH and studied via RT-PCR for cytokine analysis. RESULTS: NRH in our CVID patient population occurred in approximately 5 % of the 261 patients in our total CVID study group, initially presenting in most cases with an elevated alkaline phosphatase level. While in some patients the disease remained static, in a larger proportion a more severe disease developed characterized by portal hypertension, the latter leading to hypersplenism with neutropenia and thrombocytopenia and, in some cases, to ascites. In addition, a substantial proportion of patients either developed or presented initially with an autoimmune hepatitis-like (AIH-like) liver disease that resulted in severe liver dysfunction and, in most cases to death due to infections. The liver histologic findings in these AIH-like patients were characterized by underlying NRH pattern with superimposed interface hepatitis, lymphocytic infiltration and fibrosis. Immunologic studies of biopsies of NRH patients demonstrated the presence of infiltrating T cells producing IFN-γ, suggesting that the NRH is due to an autoimmune process. CONCLUSION: Overall, these studies provide evidence that NRH may not be benign but, can be a severe and potentially fatal disease complication of CVID that merits close monitoring and intervention.

Suppression of inflammation in ulcerative colitis by interferon-ß-1a is accompanied by inhibition of IL-13 production.

OBJECTIVE: Ulcerative colitis is associated with increased interleukin 13 (IL-13) production by natural killer T cells. Taking advantage of the inhibitory actions of interferon ß on IL-13 expression, this proof-of-concept study aimed to show that decreasing IL-13 production is associated with clinical improvement of ulcerative colitis symptoms. DESIGN: Open-label interventional drug trial. SETTING: Outpatient clinical research hospital. Patients Adult patients with active ulcerative colitis (Short Clinical Colitis Activity Index (SCCAI)≥ 5). Interventions Treatment with 30 µg IM interferon-ß-1a (Avonex) weekly for 12 weeks with 6 month follow-up. MAIN OUTCOME MEASURES: Clinical response was defined as ≥ 3 point drop in the SCCAI for at least two consecutive monitoring visits, and cytokine production was measured in cultured peripheral blood and lamina propria mononuclear cells (LPMC) before and after treatment. RESULTS: 11 of 16 patients were clinical responders, and 4 were in remission (SCCAI ≤ 2) at the end of treatment. Rectal bleeding subscores improved dramatically by week 4 (38% with frank bleeding vs 87% pretreatment). Increased IL-13 production by LPMC T cells fell significantly in clinical responders (690 ± 99 vs 297 ± 58 pg/ml p = 0.015) but was unchanged in non-responders (542 ± 83 vs 510 ± 39 pg/ml). In addition, non-responders had significantly higher production of IL-17 and IL-6 pre-treatment compared to responders. CONCLUSIONS: Interferon-ß-1a induces clinical response and remission in a large subset of patients with ulcerative colitis that is associated with significant inhibition of IL-13 production. In addition, increased IL-17 and IL-6 production is associated with no response to interferon-ß. These data provide a proof-of-concept that IL-13 is an effector cytokine in ulcerative colitis and should be a target for novel therapies.

Blau syndrome NOD2 mutations result in loss of NOD2 cross-regulatory function.

The studies described here provide an analysis of the pathogenesis of Blau syndrome and thereby the function of NOD2 as seen through the lens of its dysfunction resulting from Blau-associated NOD2 mutations in its nucleotide-binding domain (NBD). As such, this analysis also sheds light on the role of NOD2 risk polymorphisms in the LRR domain occurring in Crohn's disease. The main finding was that Blau NOD2 mutations precipitate a loss of canonical NOD2 signaling via RIPK2 and that this loss has two consequences: first, it results in defective NOD2 ligand (MDP)-mediated NF-κB activation and second, it disrupts NOD2-mediated cross-regulation whereby NOD2 downregulates concomitant innate (TLR) responses. Strong evidence is also presented favoring the view that NOD2-mediated cross-regulation is under mechanistic control by IRF4 and that failure to up-regulate this factor because of faulty NOD2 signaling is the proximal cause of defective cross-regulation and the latter's effect on Blau syndrome inflammation. Overall, these studies highlight the role of NOD2 as a regulatory factor and thus provide additional insight into its function in inflammatory disease. Mutations in the nucleotide binding domain of the CARD15 (NOD2) gene underlie the granulomatous inflammation characterizing Blau syndrome (BS). In studies probing the mechanism of this inflammation we show here that NOD2 plasmids expressing various Blau mutations in HEK293 cells result in reduced NOD2 activation of RIPK2 and correspondingly reduced NOD2 activation of NF-κB. These in vitro studies of NOD2 signaling were accompanied by in vivo studies showing that BS-NOD2 also exhibit defects in cross-regulation of innate responses underlying inflammation. Thus, whereas over-expressed intact NOD2 suppresses TNBS-colitis, over-expressed BS-NOD2 does not; in addition, whereas administration of NOD2 ligand (muramyl dipeptide, MDP) suppresses DSS-colitis in Wild Type (WT) mice it fails to do so in homozygous or heterozygous mice bearing a NOD2 Blau mutation. Similarly, mice bearing a Blau mutation exhibit enhanced anti-collagen antibody-induced arthritis. The basis of such cross-regulatory failure was revealed in studies showing that MDP-stimulated cells bearing BS-NOD2 exhibit a reduced capacity to signal via RIPK2 as well as a reduced capacity to up-regulate IRF4, a factor shown previously to mediate NOD2 suppression of NF-κB activation. Indeed, TLR-stimulated cells bearing a Blau mutation exhibited enhanced in vitro cytokine responses that are quieted by lentivirus transduction of IRF4. In addition, enhanced anti-collagen-induced joint inflammation in mice bearing a Blau mutation was accompanied by reduced IRF4 expression in inflamed joint tissue and IRF4 expression was reduced in MDP-stimulated cells from BS patients. Thus, inflammation characterizing Blau syndrome are caused, at least in part, by faulty canonical signaling and reduce IRF4-mediated cross-regulation.

NOD2 transgenic mice exhibit enhanced MDP-mediated down-regulation of TLR2 responses and resistance to colitis induction.

BACKGROUND & AIMS: Mutations in the CARD15 gene encoding NOD2 are susceptibility factors in Crohn's disease. We explored the mechanism of this susceptibility using mice that over express NOD2. METHODS: Cellular and molecular responses of mice bearing an NOD2 transgene or administered plasmids that express wild-type and mutated NOD2 constructs were examined. RESULTS: In initial studies, we showed that splenocytes from NOD2 transgenic mice as compared with littermate controls exhibit decreased interleukin (IL)-12p70 responses to peptidoglycan (PGN), a TLR2 ligand that contains muramyl dipeptide, but not other TLR ligands; in contrast, IL-12 responses to PAM(3)CSK(4), a TLR2 ligand that does not contain muramyl dipeptide, were normal. Similarly, transgenic mice as compared with controls exhibited greatly decreased IL-12p40 responses to intraperitoneal administration of PGN but not to lipopolysaccharide. In further studies, we showed using electrophoretic mobility shift assay that PGN-stimulated cells from transgenic mice exhibited decreased activation of nuclear factor kappaB. Finally, in a series of studies on the effect of the NOD2 on susceptibility to induced colitis, we found that (1) transgenic mice were highly resistant to induction of PGN colitis and partially resistant to induction of trinitrobenzene sulfonic acid (TNBS) colitis and (2) mice administered a plasmid expressing a wild-type NOD2 gene were completely resistant to TNBS colitis whereas mice administered a plasmid expressing an NOD2 gene with the Crohn's disease frameshift mutation were only slightly resistant to TNBS colitis. CONCLUSIONS: These data offer new evidence that NOD2 mutations contribute to inflammatory bowel disease by causing excessive TLR2 cytokine responses.

Nonclassical CD1d-restricted NK T cells that produce IL-13 characterize an atypical Th2 response in ulcerative colitis.

While Crohn disease (CD) has been clearly identified as a Th1 inflammation, the immunopathogenesis of its counterpart inflammatory bowel disease, ulcerative colitis (UC), remains enigmatic. Here we show that lamina propria T (LPT) cells from UC patients produce significantly greater amounts of IL-13 (and IL-5) than control cells and little IFN-gamma, whereas comparable cells from CD patients produce large amounts of IFN-gamma and small amounts of IL-13. We then show that stimulation of UC LPT cells bearing an NK marker (CD161) with anti-CD2/anti-CD28 or with B cells expressing transfected CD1d induces substantial IL-13 production. While this provided firm evidence that the IL-13-producing cell is an NK T (NKT) cell, it became clear that this cell does not express invariant NKT cell receptors characteristic of most NKT cells since there was no increase in cells binding alpha-galactosylceramide-loaded tetramers, and alpha-galactosylceramide did not induce IL-13 secretion. Finally, we show that both human NKT cell lines as well as UC CD161(+) LPT cells are cytotoxic for HT-29 epithelial cells and that this cytotoxicity is augmented by IL-13. These studies show that UC is associated with an atypical Th2 response mediated by nonclassical NKT cells producing IL-13 and having cytotoxic potential for epithelial cells.

Anti-interleukin-12 antibody for active Crohn's disease.

BACKGROUND: Crohn's disease is associated with excess cytokine activity mediated by type 1 helper T (Th1) cells. Interleukin-12 is a key cytokine that initiates Th1-mediated inflammatory responses. METHODS: This double-blind trial evaluated the safety and efficacy of a human monoclonal antibody against interleukin-12 (anti-interleukin-12) in 79 patients with active Crohn's disease. Patients were randomly assigned to receive seven weekly subcutaneous injections of 1 mg or 3 mg of anti-interleukin-12 per kilogram of body weight or placebo, with either a four-week interval between the first and second injection (Cohort 1) or no interruption between the two injections (Cohort 2). Safety was the primary end point, and the rates of clinical response (defined by a reduction in the score for the Crohn's Disease Activity Index [CDAI] of at least 100 points) and remission (defined by a CDAI score of 150 or less) were secondary end points. RESULTS: Seven weeks of uninterrupted treatment with 3 mg of anti-interleukin-12 per kilogram resulted in higher response rates than did placebo administration (75 percent vs. 25 percent, P=0.03). At 18 weeks of follow-up, the difference in response rates was no longer significant (69 percent vs. 25 percent, P=0.08). Differences in remission rates between the group given 3 mg of anti-interleukin-12 per kilogram and the placebo group in Cohort 2 were not significant at either the end of treatment or the end of follow-up (38 percent and 0 percent, respectively, at both times; P=0.07). There were no significant differences in response rates among the groups in Cohort 1. The rates of adverse events among patients receiving anti-interleukin-12 were similar to those among patients given placebo, except for a higher rate of local reactions at injection sites in the former group. Decreases in the secretion of interleukin-12, interferon-gamma, and tumor necrosis factor alpha by mononuclear cells of the colonic lamina propria accompanied clinical improvement in patients receiving anti-interleukin-12. CONCLUSIONS: Treatment with a monoclonal antibody against interleukin-12 may induce clinical responses and remissions in patients with active Crohn's disease. This treatment is associated with decreases in Th1-mediated inflammatory cytokines at the site of disease.

Both IL-12p70 and IL-23 are synthesized during active Crohn's disease and are down-regulated by treatment with anti-IL-12 p40 monoclonal antibody.

BACKGROUND: Interleukin (IL)-12p70 and IL-23 are key T helper-1 (TH1) cytokines that drive the inflammation seen in numerous models of intestinal inflammation. These molecules contain an identical p40 chain that is bound to a p35 chain in IL-12 and a p19 chain in IL-23, making both potentially susceptible to modulation by an anti-IL-12p40 monoclonal antibody (mAb). METHODS: In the present study, we sought to determine whether active inflammation in Crohn's disease (CD) is associated with the increased synthesis of both of these cytokines and whether patients treated with an anti-IL-12p40 mAb down-regulate IL-23 as well as IL-12p70 as previous reported. RESULTS: To this end we initially determined that IL-12p70 secretion by control and CD antigen-presenting cells (macrophages) in lamina propria mononuclear populations is optimized by stimulation with CD40L and interferon-gamma. In subsequent studies using these stimulation conditions we found that patients with CD manifested both increased IL-12p70 and IL-23 secretion before anti-IL-12p40 mAb treatment and normal levels of secretion of these cytokines following cessation of treatment. Antigen-presenting cells in lamina propria mononuclear cells from ulcerative colitis patients, in contrast, produced only baseline levels of IL-23. Finally, we found that IL-23-induced T cell production of IL-17 and IL-6 are also greatly reduced after antibody treatment. The latter data are parallel to those from previous studies showing that anti-IL-12p40 down-regulates IFN-gamma and tumor necrosis factor-alpha secretion. CONCLUSIONS: We conclude that CD but not ulcerative colitis is associated with high levels of both IL-12p70 and IL-23 secretion as well as the secretion of downstream effector cytokines, and that this cytokine production is down-regulated following administration of IL-12p40 mAb.

Dynamic changes in E-protein activity regulate T reg cell development.

E-proteins are TCR-sensitive transcription factors essential for intrathymic T cell transitions. Here, we show that deletion of E-proteins leads to both enhanced peripheral TGF-ß-induced regulatory T (iT reg) cell and thymic naturally arising T reg cell (nT reg cell) differentiation. In contrast, deletion of Id proteins results in reduced nT reg cell differentiation. Mechanistic analysis indicated that decreased E-protein activity leads to de-repression of signaling pathways that are essential to Foxp3 expression. Decreased E-protein binding to an IL-2Rα enhancer locus facilitated TCR-induced IL-2Rα expression. Similarly, decreased E-protein activity facilitated TCR-induced NF-κB activation and generation of c-Rel. Consistent with this, microarray analysis indicated that cells with E-protein depletion that are not yet expressing Foxp3 exhibit activation of the IL-2 and NF-κB signaling pathways as well as enhanced expression of many of the genes associated with Foxp3 induction. Finally, studies using Nur77-GFP mice to monitor TCR signaling showed that TCR signaling strength sufficient to induce Foxp3 differentiation is accompanied by down-regulation of E-protein levels. Collectively, these data suggest that TCR stimulation acts in part through down-regulation of E-protein activity to induce T reg cell lineage development.

Excess IL-12 but not IL-23 accompanies the inflammatory bowel disease associated with common variable immunodeficiency.

BACKGROUND & AIMS: Common variable immunodeficiency (CVID) patients can develop an idiopathic inflammatory bowel disease resulting in chronic diarrhea and life-threatening malabsorption. This study was designed to assess the status of the gastrointestinal tract and to define the mucosal immune abnormalities in patients with and without symptomatic gut inflammatory disease. METHODS: CVID patients underwent tests of gut absorption, peripheral blood mononuclear cell phenotyping, and upper and lower endoscopy for histology and lamina propria mononuclear cell (LPMC) cytokine production. RESULTS: CVID patients with gastrointestinal symptoms differed from asymptomatic CVID patients by having significantly longer duration of disease and lower body mass index, D-xylose absorption, serum albumin, CD4/CD45RA cells, CD3/CD25 cells, and natural killer cells. Symptomatic CVID patients showed diffuse histologic inflammatory changes in the duodenal and colonic mucosa including villus blunting, increased lamina propria and intraepithelial lymphocytes, and epithelial apoptosis, less frequently seen in asymptomatic patients. LPMCs from symptomatic CVID patients produced significantly higher T-helper (Th) 1 cytokines, interleukin-12, and interferon-gamma. Compared with the Th1 cytokines produced by LPMCs from Crohn's disease, CVID patients did not produce excess amounts of interleukin-23, interleukin-17, or tumor necrosis factor-alpha. CONCLUSIONS: The idiopathic inflammatory bowel disease associated with gastrointestinal symptoms in CVID is a unique combination of diverse histologic findings accompanied by excessive Th1 cytokine production, distinct from that in Crohn's disease. These data show that human gut mucosal inflammatory disease can occur with excess interleukin-12 and interferon-gamma production alone and provide a rationale for developing targeted therapies for this complication of CVID.