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PubMed2006

GITR modulates innate and adaptive mucosal immunity during the development of experimental colitis in mice.

BACKGROUND: Uncontrolled T cell activation and abnormal function of the innate immune system against normal enteric bacterial flora play a critical part in the pathogenesis of inflammatory bowel disease (IBD). Therefore, pharmacological strategies directed to restore the normal responsiveness of the immune system could be efficacious in the treatment of these pathological conditions. Glucocorticoid-induced tumour necrosis factor receptor (GITR)-related gene is a member of the tumour necrosis factor receptor superfamily that is constitutively expressed at high levels on regulatory T cells and at low levels on unstimulated T cells, B cells and macrophages. GITR triggering leads to activation of T effectors and reversal of suppressive function of regulatory T cells. AIM: To investigate the role of GITR in the development of experimental colitis in mice. RESULTS: Using GITR(-/-) mice, GITR deletion protected against 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis by reducing innate immune responses and effector T cell activity. Effector T cells isolated from GITR(-/-) mice were less effective than T cells isolated from GITR(+/+) mice to transfer colitis in immunodeficient mice. Blocking the GITR/ligand for GITR (GITRL) signal by giving soluble GITR prevented TNBS-induced colitis in normal GITR(+/+) and also in lymphocyte-deficient SCID mice. CONCLUSIONS: Collectively, these data suggest that GITR plays a critical part in regulating both acquired and innate mucosal immune responses during the development of experimental colitis in mice. Therefore, targeting the GITR/GITRL system signalling may represent a potential pharmacological tool for the treatment of IBD.

Animals↗
PubMed1995

Histological discrimination of idiopathic inflammatory bowel disease from other types of colitis.

AIMS: To assess the value of histology in diagnosing inflammatory bowel disease (IBD) in colorectal biopsy specimens. METHODS: Retrospective, double blind evaluation of colorectal biopsy specimens from 41 patients with colitis (28 with ischaemic colitis and 13 with acute self-limited colitis) and 84 patients with IBD (42 with Crohn's disease and 42 with ulcerative colitis). RESULTS: The features distinguishing IBD from other forms of colitis included distorted architecture, lymphocyte and plasma cell infiltrate, excess of polymorphonuclear leucocytes, polymorphonuclear cryptitis, crypt abscesses, and basal lymphoid aggregates. The features discriminating between Crohn's disease and ulcerative colitis included an irregular or villous surface, distorted architecture, decrease in mucus content, and polymorphonuclear cryptitis. Using multivariate analysis, 90% of patients with Crohn's disease and 71% of those with ulcerative colitis were correctly classified, the former being strongly defined by epithelioid granulomas, microgranulomas and isolated giant cells, and the latter best defined by an irregular or villous surface, decrease in mucus content and crypt atrophy. CONCLUSIONS: Examination of colorectal biopsy specimens is a reliable method for diagnosing IBD. In the absence of epithelioid granulomas, microgranulomas and isolated giant cells a diagnosis of Crohn's disease is based on the absence of histological criteria favouring ulcerative colitis. The histological spectrum of indeterminate colitis remains to be clarified.

Adolescent↗
PubMed2003

Lymphocytic infiltration and expression of inducible nitric oxide synthase in human duodenal and colonic mucosa is a characteristic feature of ankylosing spondylitis.

OBJECTIVE: In patients with ankylosing spondylitis (AS), inflammatory processes have been detected in the ileal and colonic mucosa. The inducible isoform of nitric oxide synthase (iNOS) may be expressed early in the inflammatory process. We investigated iNOS activity and lymphocytic infiltration in the duodenum and colon in patients with AS and ulcerative colitis compared with controls. METHODS: Gastroscopy with duodenal biopsies and/or colonoscopy with biopsies were conducted in 42 patients with AS treated or not treated with nonsteroidal antiinflammatory drugs (NSAID), in 15 with ulcerative colitis, and in 46 controls. Lymphocytic infiltration in the lamina propria and intraepithelial infiltration were quantified by histological score. iNOS expression was assessed by immunohistochemistry with monoclonal antibodies, and iNOS activity was determined by radiochemical assay. RESULTS: Endoscopic examination of the gastroduodenal or colonic mucosa did not reveal macroscopic lesions in the AS patients. In the duodenum, mucosal lymphocytic infiltration was found in 83.3% of the AS group compared to 48.6% of controls (p = 0.02), and was independent of the NSAID intake. Intraepithelial lymphocyte infiltration was increased in both duodenum and colon in AS patients compared to controls. iNOS activity in duodenum and colon and expression of iNOS protein in lamina propria inflammatory cells was increased in AS patients compared to controls. CONCLUSION: Lymphocytic infiltration and iNOS expression and activity were detected in duodenal and colonic mucosa from patients with AS. Such findings may indicate an inflammatory process in the small intestine and colon of patients with AS.

Adult↗
PubMed2005

Xanthogranulomatous appendicitis.

Xanthogranulomatous inflammation is an uncommon, though well-recognized entity that has been described in various organs but mostly commonly in the kidney and gallbladder. There have been few reports of its occurrence in the appendix. We report a 39-year-old man who presented with fever, right lower quadrant abdominal pain and mass. Abdominal computed tomography (CT) revealed diffuse wall thickening over the terminal ileum and cecum with involvement of the mesentery. CT-guided biopsy showed colitis with infiltration of lymphocytes, neutrophils and eosinophils. The patient's illness responded to intravenous antibiotics, but relapsed after switching to oral antibiotics. After the second course of intravenous antibiotics was given without resolution of symptoms, exploratory laparotomy was performed. Although operative findings favored colitis of the cecum, cancer of the cecum could not be completely ruled out. Right hemicolectomy was done and pathology confirmed the diagnosis of xanthogranulomatous appendicitis. This case illustrates that xanthogranulomatous appendicitis may mimic a locally advanced cancer, has a benign course, and can be cured by surgical resection.

Adult↗
PubMed1999

Role of inducible nitric oxide synthase in the regulation of VCAM-1 expression in gut inflammation.

The objectives of this study were to assess the role of the inducible isoform of nitric oxide synthase (iNOS) on vascular cell adhesion molecule 1 (VCAM-1) expression in vivo in an acute model of inflammation induced in iNOS-deficient (iNOS-/-) mice and compare these data to those obtained by pharmacological inhibition of iNOS in a CD4+ T lymphocyte-dependent model of chronic colitis. VCAM-1 expression was quantified in vivo using the dual radiolabel monoclonal antibody technique. We found that intraperitoneal injection of 10 microg/kg tumor necrosis factor-alpha (TNF-alpha) enhanced VCAM-1 expression by approximately twofold in the colon, cecum, and stomach but not small intestine in iNOS-/- mice compared with TNF-alpha-injected wild-type mice. Injection of wild-type mice with 25 microg/kg TNF-alpha further enhanced VCAM-1 expression by approximately twofold compared with wild-type mice injected with 10 microg/kg TNF-alpha; however, VCAM-1 expression was not further enhanced in any gastrointestinal organ system in iNOS-/- mice. In a second series of experiments, we found that continuous inhibition of iNOS using oral administration of NG-iminoethyl-L-lysine did not alter the enhanced levels of VCAM-1 expression in the colon nor did it alter the severity of colonic inflammation in SCID mice reconstituted with CD4+, CD45RB(high) T cells. We conclude that iNOS may regulate VCAM-1 expression in acute inflammation; however, this effect is modest and tissue specific and occurs only when VCAM-1 expression is submaximal. iNOS does not appear to modulate VCAM-1 expression in an immune model of chronic colitis.

Animals↗
PubMed1985

Animal models of inflammatory bowel disease--an overview.

It is obvious from the above discussion that, whereas no really clear-cut animal model of IBD has been established, a number of specific insights into the nature of the human illness can be derived from the study of naturally occurring and induced gastrointestinal inflammations occurring in animals. One of the most important emerges from the finding that both immune complex deposition in the gastrointestinal tract as well as stimulation of the mucosal T-cell system results in an ulcerative colitis-like gastrointestinal inflammation. The simplest explanation of the fact that vastly different methods of inducing immune-mediated injury in the gastrointestinal tract can lead to a similar kind of gastrointestinal inflammation is that the inflammatory response in the gastrointestinal tract is rather restricted in its overall pathologic appearance and that the histologic lesions characteristic of ulcerative colitis and Crohn's disease can arise from primary disturbance of the B-cell system, the T-cell system, or both. Another explanation of this fact, however, is that no matter what the initial immunological disorder may be, the mechanism underlying the gastrointestinal inflammation ultimately comes to involve a response to materials in the mucosal environment so that pathologic events are inevitably channeled into an inflammatory pathway that is either ulcerative colitis-like or Crohn's disease-like in its final configuration. This second explanation is buttressed by other findings derived from the study of animal models which, in general, suggest that no matter what the initial result, an immunologic interaction against a constituent of the bowel flora determines the ultimate course of the gastrointestinal inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Evidence of Epstein-Barr virus infection in ulcerative colitis.

BACKGROUND AND AIM: The aetiology of ulcerative colitis is still controversial, however, recent studies have emphasised the possible role of infectious agents or ingested substances and their breakdown products, which might activate immune-mediated mechanisms eventually leading to tissue damage. Aim of this investigation was to ascertain the occurrence and the potential role of Epstein-Barr virus infection in large bowel mucosa of ulcerative colitis patients. PATIENTS AND METHODS: Twenty-three biopsies and six total colectomies from 17 patients were analysed for the expression of Epstein-Barr virus proteins and RNAs. Polymerase chain reaction experiments were also carried out to detect Epstein-Barr virus DNA. For comparison, ten biopsies from patients with Crohn's disease, ten biopsies from patients with different types of colitis, seven biopsies and five surgical margins of normal colonic mucosa from the small and large bowels were studied (controls). RESULTS: Six biopsies and four colectomies from seven ulcerative colitis patients showed scattered lymphocytes expressing nuclear EBER 1-2 and harbouring polymerase chain reaction-amplifiable Epstein-Barr virus-DNA. In some cases, linear viral DNA (typical of lytic Epstein-Barr virus infection) was also found. Epithelial cells were invariably negative in all cases. All control tissues from non-ulcerative colitis patients were also invariably non-reactive. CONCLUSION: Evidence of Epstein-Barr virus infection in the mucosal inflammatory cells of ulcerative colitis patients suggests a possible role of this virus in the chronicity of ulcerative colitis.

Adult↗
PubMed1996

Expanded CD4+CD45RO+ phenotype and defective proliferative response in T lymphocytes from patients with Crohn's disease.

BACKGROUND & AIMS: An abnormal immune response may play a pathogenic role in Crohn's disease. The aim of this study was to determine the role of regulatory T cells in Crohn's disease. METHODS: T-cell phenotype and function were studied in blood lymphocytes from patients with Crohn's disease and a control group consisting of healthy donors and patients with ulcerative colitis. RESULTS: Flow cytometric studies showed a significant increase in the percentage of CD3+DR+ and CD4+CD45RO+ T cells in patients with Crohn's disease. T cells from patients with Crohn's disease and ulcerative colitis showed a defective proliferative response after stimulation with surface mitogenic ligands (phytohemagglutinin and anti-CD28 or anti-CD3 antibodies). Soluble interleukin-2 receptor alpha was augmented in the Crohn's disease and ulcerative colitis groups. In the Crohn's disease group, impairment of T-lymphocyte proliferation was normalized by exogenous interleukin 2, although endogenous interleukin-2 production and interleukin-2 receptor alpha expression were normal. CONCLUSIONS: An in vivo expansion of CD4+ T lymphocytes with memory phenotype and impaired T-cell proliferation that can be restored by pharmacological amounts of interleukin 2 was found in patients with Crohn's disease. There is a severe immunodisturbance in the T-cell compartment of patients with either clinically active or inactive Crohn's disease.

Adult↗
PubMed1993

Enterocolic lymphocytic phlebitis. Clinical, radiologic, and pathologic features.

Venous compromise as a cause of ischemic colitis and enteritis is infrequent. Enterocolic lymphocytic phlebitis, a rare cause of such compromise, to our knowledge has been reported in only three patients. We describe a patient with this condition who had hematochezia and a cecal mass that was mistaken endoscopically and radiologically for carcinoma and required resection. The mass, which was ulcerated, was due to intense submucosal edema. The patient had no history of taking hydroxyethylrutoside, a drug used in Europe in treating varicose veins that has been implicated in all three previously reported cases. This entity is characterized by a mixed T- and B-cell vasculitis affecting veins exclusively in the wall and mesentery of the colon and small bowel, without systemic involvement, leading to fibrointimal proliferation, thrombosis, venous occlusion, and subsequent edema and ischemic necrosis. It should be distinguished from other enterocolic phlebitides, including Behçet disease, systemic lupus erythematosus, and myointimal hyperplasia of mesenteric veins, and can be treated by local excision of the affected bowel.

Aged↗
PubMed1995

Antibodies to interleukin 12 abrogate established experimental colitis in mice.

In this study, we describe a novel murine model of chronic intestinal inflammation induced by the hapten reagent 2,4,6-trinitrobenzene sulfonic acid (TNBS). Rectal application of low doses of TNBS in BALB/c and SJL/J mice resulted in a chronic transmural colitis with severe diarrhea, weight loss, and rectal prolapse, an illness that mimics some characteristics of Crohn's disease in humans. The colon of TNBS-treated mice on day 7 was marked by infiltration of CD4+ T cells; furthermore, in situ polymerase chain reaction studies revealed high levels of interferon (IFN)-gamma mRNA in diseased colons. Isolated lamina propria (LP) CD4+ T cells from TNBS-treated mice stimulated with anti-CD3 and anti-CD28 antibodies exhibited a Th1 pattern of cytokine secretion: a 20-50-fold increase in IL-2 and IFN-gamma levels and a 5-fold decrease in IL-4 levels as compared with those of stimulated LP CD4+ T cells from control BALB/c mice. Administration of monoclonal anti-IL-12 antibodies to the TNBS-treated mice both early (at 5 d) and late (at 20 d) after induction of colitis led to a striking improvement in both the clinical and histopathological aspects of the disease and frequently abrogated the established colitis completely. Furthermore, LP CD4+ T cells isolated from anti-IL-12-treated mice failed to secrete IFN-gamma upon in vitro stimulation. In summary, the data demonstrate the pivotal role of IL-12 and IFN-gamma in a TNBS-induced murine model of chronic intestinal inflammation. Furthermore, they suggest the potential utility of anti-IL-12 antibodies in patients with Crohn's disease.

Animals↗
PubMed1997

Intestinal disease in acquired immunodeficiency: evaluation by CT.

Intestinal symptoms affect most AIDS patients at some point in their disease. The purpose of this study was to evaluate the use of CT in this setting. A total of 339 abdominal CT exams were reviewed for signs of intestinal disease. Abdominal CT scans of 45 patients with intestinal symptoms were compared with colonoscopy and histologic data. The CT results were correlated with CD4( +) T-lymphocyte counts and patient survival. More than 14 % of all abdominal CT exams displayed signs of enteric disease. Of the 45 patients studied with both CT and colonoscopy, 35 (78 %) had signs of intestinal disease by CT. Of these 35 patients, colonoscopic signs of an intestinal lesion were found in 29 and histologic proof of disease was established in 30 cases. Colonoscopy and histology detected 8 lesions missed by CT. There were 14 cases of unspecific colitis, 15 cases of cytomegalovirus (CMV) colitis, and 4 cases of enteric tuberculosis as per biopsy. Five patients presented with Kaposi's sarcoma and 1 with a non-Hodgkin's lymphoma. Neither colonoscopic nor CT signs of intestinal disease did reliably distinguish between histologic subgroups. Specifically, CMV colitis could not be distinguished from unspecific colitis. CD4( +) T-lymphocyte counts for histologic subgroups were not significantly different, either. No colonoscopic or histologic feature predicted survival, whereas low CD4 counts and ascites on CT indicated a poor prognosis. Whereas CT detects signs of intestinal disease in most AIDS patients, these signs remain largely unspecific. Colonoscopy and biopsies provide no consistently valid standard with which to compare CT because of controversial sensitivity and specificity of these methods. The CT technique detects small bowel as well as extraintestinal disease. Therefore, CT is an important diagnostic modality in abdominal disease of immunocompromised patients.

AIDS-Related Opportunistic Infections↗
PubMed2003

Basiliximab (anti-CD25) in combination with steroids may be an effective new treatment for steroid-resistant ulcerative colitis.

BACKGROUND: Steroid resistance represents a major clinical problem in the treatment of ulcerative colitis. In vitro, interleukin-2 renders lymphocytes steroid resistant. AIM: To explore the therapeutic potential of interleukin-2 receptor blockade in steroid-resistant ulcerative colitis with both in vitro measures and a pilot in vivo study. METHODS: Ten patients with steroid-resistant ulcerative colitis received a single bolus of 40 mg of intravenous basiliximab plus steroid treatment in an open-label, uncontrolled, 24-week study. The outcome was assessed using the Ulcerative Colitis Symptom Score, rectal biopsy and Inflammatory Bowel Disease Questionnaire. Lymphocyte steroid sensitivity was measured in vitro in 39 subjects in the presence or absence of basiliximab. RESULTS: Nine of the 10 patients achieved clinical remission within 8 weeks. At 24 weeks, seven patients were in clinical remission. Marked improvement in the Ulcerative Colitis Symptom Score was seen by 1 week (P = 0.004) and on rectal biopsy and Inflammatory Bowel Disease Questionnaire by 2 weeks (both P < 0.05). Improvements persisted to 24 weeks (Ulcerative Colitis Symptom Score, Inflammatory Bowel Disease Questionnaire, both P < 0.005). Eight of the nine responders relapsed (median, 9 weeks), but remission was re-achieved with further corticosteroids and the addition of azathioprine. At 24 weeks, seven patients were in full clinical remission, five off all steroid therapy. In vitro measurement of lymphocyte steroid sensitivity demonstrated steroid resistance in 22% of subjects. All were rendered steroid sensitive in the presence of basiliximab. CONCLUSIONS: Basiliximab appears to be effective at inducing remission in steroid-resistant ulcerative colitis. In vitro, basiliximab also produced a dramatic increase in lymphocyte steroid sensitivity in healthy subjects. Confirmation in randomized controlled studies is required.

Adult↗
PubMed2000

CMV complications in common variable immunodeficiency.

A patient suffering from common variable immunodeficiency is described, who developed a myelitis under treatment with glucocorticosteroids. Later on, autoimmune complications had to be treated with azathioprine. An exacerbation of the myelitis, retinitis, encephalitis and colitis was observed and a cytomegalovirus infection diagnosed. This infection does not represent a typical complication of common variable immunodeficiency. A functional NK cell defect was detected that may contribute to susceptibility for cytomegalovirus infection in addition to immunosuppressive therapy.

Adult↗
PubMed1995

Cytomegalovirus colitis in AIDS: CT features.

OBJECTIVE: The purpose of this study was to determine the CT features of cytomegalovirus colitis in patients with AIDS. MATERIALS AND METHODS: Abdominal CT scans of 24 patients with biopsy-proved cytomegalovirus colitis (colonoscopy, n = 14; sigmoidoscopy, n = 8; surgery, n = 2) were jointly reviewed by two observers. Patients were men 26-68 years old (mean age, 39 years; SD, 9 years) with CD4 counts of 3-129 mm3 (mean, 32 mm3; SD, 34 mm3). The mean interval between CT and biopsy was 6 days (range, 0-20 days; SD, 6 days). Scans were assessed for colonic wall thickening (> or = 4 mm), ulceration, mural edema, pericolonic stranding, ascites, lymphadenopathy, and thickening of the small-bowel wall. Mural involvement was recorded as asymmetric or circumferential. Disease location was recorded as ascending colon, transverse colon, descending colon, rectosigmoid colon, or pancolonic. RESULTS: Colonic wall thickening of 8 to 33 mm (mean, 15 mm; SD, 6 mm) was seen in 22 patients. One patient had pancolonic involvement. The ascending colon was involved in 13, the transverse colon in five, the descending colon in 10, and the rectosigmoid colon in 16. Circumferential colonic thickening was seen in 17 patients. Deep mural ulceration was seen in 15 patients, mural edema in 15, pericolonic stranding in 23, ascites in 10, lymphadenopathy in four, and small-bowel involvement in 10. Two patients had appendicitis. Three patients had perforations (two rectal, one cecal). One patient had a giant rectal ulcer. CONCLUSION: Although many of the CT features of cytomegalovirus colitis are nonspecific, the diagnosis should be suggested when CT shows colonic wall thickening, particularly if the thickening is associated with mural ulceration in patients with AIDS and CD4 counts of less than 200 mm3.

AIDS-Related Opportunistic Infections↗