Increased interleukin-2 messenger RNA in the intestinal mucosal lesions of Crohn's disease but not ulcerative colitis

Correlation of ex vivo cytokine secretion profiles with scoring indices in ulcerative colitis

BACKGROUND

In ulcerative colitis, the complexity of mucosal cytokine secretion profiles and how they correlate with endoscopic and clinical scores is still unclear.

METHODS

In this study, we collected fresh biopsies from UC patients to investigate which cytokines are produced in ex vivo culture conditions, a platform increasingly used for testing of novel drugs. Then, we correlated cytokine production with several scoring indices commonly used to assess the severity of the disease.

RESULTS

Increased levels of IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, TNFα and IFNɣ were produced by biopsies of UC patients compared to non-IBD controls. Our results show a better correlation of cytokine levels with Mayo Endoscopic Subscore (MES) and Mayo score, than the more complex Ulcerative Colitis Endoscopic Index of Severity (UCEIS). Out of 10 measured cytokines, eight correlated with MES, six with Mayo score and only three with UCEIS, due to the partial increase in cytokine secretion observed in donors with UCEIS = 7-8. When we analysed individual subscores within the UCEIS, Vascular Network subscore showed a correlation similar to MES (7/10 cytokines), while Bleeding as well as Erosions and Ulcers subscores correlated with only 3/10 cytokines, similarly to the total UCEIS.

CONCLUSIONS

Our findings suggest that choosing biopsies from donors with MES = 2-3 and UCEIS = 2-6 from areas with no bleeding and no superficial and/or deep ulcers could enable a deeper insight into the cytokine profile of the inflamed tissue and represent a better tool for studying potential therapeutic targets and evaluation of novel therapies.

Genome-wide association studies of inflammatory bowel disease in German shepherd dogs

Canine Inflammatory Bowel Disease (IBD) is considered a multifactorial disease caused by complex interactions between the intestinal immune system, intestinal microbiota and environmental factors in genetically susceptible individuals. Although IBD can affect any breed, German shepherd dogs (GSD) in the UK are at increased risk of developing the disease. Based on previous evidence, the aim of the present study was to identify single nucleotide polymorphisms (SNPs), which may confer genetic susceptibility or resistance to IBD using a genome-wide association study (GWAS). Genomic DNA was extracted from EDTA blood or saliva samples of 96 cases and 98 controls. Genotyping of cases and controls was performed on the Canine Illumina HD SNP array and data generated was analyzed using PLINK. Several SNPs and regions on chromosomes 7,9,11 and 13 were detected to be associated with IBD using different SNP-by-SNP association methods and FST windows approach. Searching one Mb up-and down-stream of the most significant SNPs, as identified by single SNP analysis as well as 200Kb before and after the start and the end position of the associated regions identified by FST windows approach, we identified 63 genes. Using a combination of pathways analysis and a list of genes that have been reported to be involved in human IBD, we identified 16 candidate genes potentially associated with IBD in GSD.

Innate Lymphoid Cells in Intestinal Inflammation

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the intestine that encompasses Crohn's disease (CD) and ulcerative colitis. The cause of IBD is unknown, but the evidence suggests that an aberrant immune response toward the commensal bacterial flora is responsible for disease in genetically susceptible individuals. Results from animal models of colitis and human studies indicate a role for innate lymphoid cells (ILC) in the pathogenesis of chronic intestinal inflammation in IBD. ILC are a population of lymphocytes that are enriched at mucosal sites, where they play a protective role against pathogens including extracellular bacteria, helminthes, and viruses. ILC lack an antigen-specific receptor, but can respond to environmental stress signals contributing to the rapid orchestration of an early immune response. Several subsets of ILC reflecting functional characteristics of T helper subsets have been described. ILC1 express the transcription factor T-bet and are characterized by secretion of IFNγ, ILC2 are GATA3⁺ and secrete IL5 and IL13 and ILC3 depend on expression of RORγt and secrete IL17 and IL22. However, ILC retain a degree of plasticity depending on exposure to cytokines and environmental factors. IL23 responsive ILC have been implicated in the pathogenesis of colitis in several innate murine models through the production of IL17, IFNγ, and GM-CSF. We have previously identified IL23 responsive ILC in the human intestine and found that they accumulate in the inflamed colon and small bowel of patients with CD. Other studies have confirmed accumulation of ILC in CD with increased frequencies of IFNγ-secreting ILC1 in both the intestinal lamina propria and the epithelium. Moreover, IL23 driven IL22 producing ILC have been shown to drive bacteria-induced colitis-associated cancer in mice. Interestingly, our data show increased ILC accumulation in patients with IBD and primary sclerosing cholangitis, who carry an increased risk of developing colorectal cancer. ILC may play an important amplifying role in IBD and IBD-associated cancer, through secretion of inflammatory cytokines and interaction with other immune and non-immune cells. Here, we will review the evidence indicating a role for ILC in the pathogenesis of chronic intestinal inflammation.

Role of Vitamin D in Inflammatory Bowel Disease

Vitamin D is a secosteroid hormone that possesses immunomodulatory properties and has been demonstrated to potentially influence inflammatory bowel disease (IBD) pathogenesis and activity. Epidemiologic data have associated vitamin D deficiency with an increased risk of IBD, hospitalizations, surgery, and loss of response to biologic therapy. Conversely, IBD itself can lead to vitamin D deficiency. This bidirectional relationship between vitamin D and IBD suggests the need for monitoring and repletion of vitamin D, as needed, in the IBD patient. This review discusses the role of vitamin D in IBD and provides practical guidance on vitamin D repletion.

Treatment of perianal fistulas with human embryonic stem cell-derived mesenchymal stem cells: a canine model of human fistulizing Crohn's disease

Aim: To evaluate the safety and efficacy of intralesional injection of human embryonic stem cell (hESC)-derived mesenchymal stem/stromal cells (MSCs) in canine anal furunculosis dogs. Materials & methods: Dogs naturally develop an immune-mediated disease called canine anal furunculosis, which shares many features with human fistulizing Crohn's disease. Results: The hESC-MSCs were well tolerated and 1 month postinjection, accompanied by reduced serum levels of IL-2 and IL-6, two inflammatory cytokines associated with Crohn's disease. All six dogs were found to be completely free of fistulas at 3 months postinjection. However, at 6 months, two dogs had some fistula relapse. Conclusion: Results of this study provide the first evidence of the safety and therapeutic potential of hESC-MSCs in a large animal model.

Cytokines in inflammatory bowel disease

Over the past decade, much has been learned regarding the role of various cytokines in the pathogenesis of inflammatory bowel disease. Several cytokine ‘knockout’ models in mice have been shown to develop colitis, while alterations in the production of various cytokines has been documented in human Crohn's disease and ulcerative colitis. In recent years, attempts have been made to treat these diseases through modulation of cytokine production or action. This review focuses on the cytokines that have been implicated in the pathogenesis of inflammatory bowel disease. The evidence for and against a role for particular cytokines in intestinal inflammation is reviewed, as is the experimental and clinical data suggesting that cytokines are rational targets for the development of new therapies.

The role of cytokines in inflammatory bowel disease

Cytokines play an important role in the development and persistence of the inflammatory lesions seen in Crohn's disease and ulcerative colitis. This review discusses the current thinking of the role of cytokines in chronic intestinal inflammation including the involvement of immunoregulatory cytokines within the Th1 and Th2 subsets.

Patients with inflammatory bowel disease may have a transforming growth factor-beta-, interleukin (IL)-2- or IL-10-deficient state induced by intrinsic neutralizing antibodies

Ulcerative colitis (UC) and Crohn's disease (CD) are considered to be immunologically mediated disorders that share certain features with murine models of colitis. Whether any of these models are physiologically relevant to the human condition remains controversial. The hypothesis is that increased amounts of antibodies neutralizing transforming growth factor (TGF)-beta, interleukin (IL)-2 or IL-10 create a relative immunodeficient state in inflammatory bowel disease (IBD) that predisposes to disease. To evaluate this, serum samples from patients with UC or CD and from normal healthy individuals were studied by enzyme-linked immunosorbent assays. Antibodies recognizing TGF-beta were most prevalent in UC (P<0.01); anti-IL-10 antibodies were elevated in CD (P<0.05), while anti-IL-2 antibodies were the same for all three groups. Importantly, the percentage of IBD patients with at least one of the antibody levels greater than any control value was 30% for UC and 33% for CD. To verify the presence of these antibodies, immobilized TGF-beta was exposed to UC sera and the attached proteins identified by Western blot assay. The proteins proved to be exclusively immunoglobulin (Ig) G. To evaluate the neutralizing activity of these antibodies, cytokine-specific IgG from subjects in each group of patients was incubated with TGF-beta, IL-2 or IL-10 before addition to a bioassay with changes in viability determined by a colorimetric analysis. Antibodies from most individuals in all three groups neutralized the action of each cytokine. This study shows that about one-third of IBD patients may have a relative deficiency of TGF-beta, IL-2 or IL-10 due to an increase in neutralizing antibodies in their sera.

Treatment strategies for amyloid A amyloidosis

BACKGROUND

Amyloid A (AA) amyloidosis is a serious complication of a wide range of chronic inflammatory, infectious and neoplastic diseases. A longstanding overproduction of the liver-synthesised cytokine-induced acute phase serum amyloid A (SAA) protein is a key event in the pathogenetic cascade leading to the deposition of AA amyloid in tissues and organs.

OBJECTIVE

The aim of the study was to critically review treatment strategies in AA amyloidosis.

METHODS

A systematic literature review was conducted based on PubMed (January 1980 - April 2008) and selected conference abstracts.

RESULTS/CONCLUSIONS

The current strategy for the treatment of AA amyloidosis is firmly based on the knowledge of the underlying pathogenetic mechanism and aims at reducing the amyloid precursor (SAA) load by intensive anti-inflammatory/immunosuppressive therapy and, in selected instances, anticytokine (TNF-alpha, IL-1beta or IL-6 blockade) therapy, or, when applicable, the eradication of an existing infectious focus (surgery, antimicrobial drugs). Emerging strategies focus on the dissolution of the amyloid deposits using small molecules that either interact with the glycosaminoglycans or the fibril component of the deposits, or deplete amyloid P component.

Oxymatrine improves TNBS-induced colitis in rats by inhibiting the expression of NF-kappaB p65

Inflammatory bowel disease is thought to be regulated by the balance between Th1 and Th2 cytokines secreted by T cells, and NF-kappaB p65 also plays a predominant role in the intestinal inflammation. We evaluated the potency of oxymatrine, one of active components of Sophora Root, in inhibiting the immune responses and inflammation in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. The inflammation was markedly ameliorated in the oxymatrine-treated rats. The level of IL-2 was increased and that of IL-10 was decreased in colon tissue in the rat model, which was reversed by the treatment of oxymatrine. Moreover, the elevated expression of NF-kappaB p65 in colon tissue in the model was also improved by oxymatrine treatment. Our results suggest that oxymatrine might be beneficial for the abnormal immune responses and inflammation by regulating the unbalance of Th1 and Th2 cytokines secretion and inhibiting the expression of NF-kappaB p65 in colon tissue.

Detection of cytokine mRNA expression by PCR

Assessment of cytokine expression during an immune response is a critical requirement for studies of basic immune mechanisms and the pathogenesis of disease. As an alternative to measuring cytokine protein levels, analysis of cytokine mRNA may be appropriate, because production of many cytokines is primarily transcriptionally regulated. Therefore, the level of cytokine mRNA present in a sample may serve as a good estimate of the level of cytokine protein present. This unit outlines the amplification of IL-2 mRNA from clinical biopsy specimens by the polymerase chain reaction (PCR), but the approach can be readily modified to study any cytokine RNA of interest in biopsies or small samples. In the Basic Protocol, cDNA is synthesized from the sample RNA by reverse transcriptase; to control for experimental variation in both the reverse transcription and PCR amplification steps, an internal control RNA is included in the reaction. Together, the reverse-transcribed cDNAs are amplified by PCR.

Intestinal epithelial cells from inflammatory bowel disease patients preferentially stimulate CD4+ T cells to proliferate and secrete interferon-gamma

Previous studies have suggested that intestinal epithelial cells (IECs) have the capacity to function as nonprofessional antigen presenting cells that in the normal state preferentially activate CD8+ T cells. However, under pathological conditions, such as those found in inflammatory bowel disease (IBD), persistent activation of CD4+ T cells is seen. The aim of this study was to determine whether the IBD IECs contribute to CD4+ T cell activation. Freshly isolated human IECs were obtained from surgical specimens of patients with or without IBD and cocultured with autologous or allogeneic peripheral blood T lymphocytes. Cocultures of normal T cells and IECs derived from IBD patients resulted in the preferential activation of CD4+ T cell proliferation that was associated with significant IFN-gamma, but not IL-2, secretion. Cytokine secretion and CD4+ T cell proliferation was inhibited by pretreatment of the IBD IECs with the anti-DR MAb L243. In contrast, normal IECs stimulated the proliferation and cytokine secretion by CD4+ T cells to a significantly lesser degree than IBD IECs. Furthermore, blockade of human leukocyte antigen-DR had a lesser effect in the normal IEC-CD4+ T cell cocultures. We conclude that IECs can contribute to the ongoing CD4+ T cell activation seen in IBD. We suggest that the apparent differences between the secreted levels of IFN-gamma indicate that it may play a dual role in intestinal homeostasis, in which low levels contribute to physiological inflammation whereas higher levels are associated with an uncontrolled inflammatory state.

[Cytokines in the pathogenesis of inflammatory bowel diseases]

Inflammatory bowel disease (IBD) is produced by an exaggerated response to bacterial flora within the intestinal mucous, in which both environmental and genetic factors are involved. T lymphocytes are involved during the genesis and maintenance of IBD, and their cytokine profile in Crohn's disease (mostly Th1 cytokines) is different from that in ulcerative colitis (mainly Th2 cytokines). After the inflammatory response has been established, the balance between proinflammatory and regulatory cytokines determines the degree of mucosal damage and the form of presentation. A deeper knowledge of the immunological mechanisms involved in IBD has opened new research lines aimed to the development of new therapies such as the neutralization of proinflammatory cytokines with antibodies and the administration of antiinflammatory cytokines, which are currently at different stages of research.

Overview of role of the immune system in the pathogenesis of inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are caused by the over-activity of the immune system. Current and novel therapies are designed to dampen these over-active responses. Analysis of the types of immune responses ongoing in diseased mucosa of inflammatory bowel disease patients has revealed that CD and UC are fundamentally different diseases. The former has the molecular imprints of a Th1 dominant cell-mediated hypersensitivity response whereas the latter appears to involve antibody-mediated hypersensitivity.

Control of systemic and local inflammation with transforming growth factor beta containing formulas

Enteral nutrition therapy with liquid diet has been shown to be effective in achieving clinical remission in intestinal Crohn's disease. The mechanism of action of this therapy, however, is still poorly understood. As part of our assessment of the action of 3 related polymeric enteral therapies, we have used a variety of techniques to document the histological and cytokine responses, in the mucosa and, systemically, to these treatments. The feeds studied (AL110, Modulen IBD and ACD004 [Nestle, Vevey, Switzerland]) all have casein as the protein source, are lactose free and are rich in transforming growth factor beta (TGF-beta). They have all been shown to induce clinical remission associated with mucosal healing. In the case of Modulen IBD, as well as mucosal macroscopic and histological healing there was a fall in mucosal proinflammatory cytokines: interleukin-1 mRNA in colonic and ileal, interleukin-8 mRNA in the colon and interferon gamma mRNA in the ileum, but a rise in the regulatory cytokine TGF-beta mRNA in the ileum. These results indicate that these formulas are influencing the disease process itself, and thus suggest that the clinical remission achieved is a result of a reduction in inflammation, rather than a consequence of some other nutrition effect.

Alpha CD 2 mAb treatment safely attenuates adoptive transfer colitis

Increased proliferation, defective apoptosis, and cytokine dysregulation of T lymphocytes are thought to be important for the pathogenesis of inflammatory bowel disease. Since these phenomena can be corrected by alpha CD 2 mAb, we asked whether CD2 directed immunotherapy safely prevents and/or ameliorates adoptive transfer colitis. Colitis was induced by transfer of CD4(+) T cell blasts to syngenic RAG 1(-/-) mice or CD 45 RB(high) CD4(+) T cells to SCID mice. The alpha CD 2 mAb 12-15 or rat IgG was given, starting either initially or upon first signs of colitis. Disease activity was assessed by clinical monitoring, microscopic scoring, hemoccult, endoscopy, and blood count analysis. Cytokine production of stimulated LPL was measured by ELISA and cell proliferation by [(3)H]-thymidine incorporation. Parasite control was analyzed in a murine model of infection with Toxoplasma gondii. The alpha CD 2 mAb significantly increased mean survival time when starting at transfer of blasts (survival >35 days: alpha CD 2 69% vs 0% of controls, P<0.001). In the SCID colitis model hematochezia and macroscopic colitis were delayed. When used in established T-cell blast colitis, the benefit was less pronounced, even in combination with dexamethasone (mean survival+/-s.e.m.: alpha CD 2+dexa: 13.5+/-2.9 vs dexa+IgG: 6.3+/-1.0, P<0.05). In the preventive experiment the alpha CD 2 mAb markedly reduced IL-2 secretion and T-cell proliferation. The immune response towards Toxoplasma gondii was not impaired. These studies show for the first time that CD2 directed immunotherapy can attenuate or delay adoptive transfer colitis and ameliorate established colitis. Most likely inhibition of IL-2 secretion and T-cell proliferation are responsible for these effects. Still, immune defence towards T. gondii is maintained.

Acellular Bordetella pertussis vaccine enhances mucosal interleukin-10 production, induces apoptosis of activated Th1 cells and attenuates colitis in Galphai2-deficient mice

Mice deficient for the inhibitory G protein subunit alpha2 (Galphai2(-/-)) spontaneously develop a progressive inflammatory bowel disease resembling ulcerative colitis, and have a T helper 1 (Th1)-dominated immune response prior to onset of colitis, which is further augmented after the onset of disease. The present study was performed to investigate whether the Galphai2(-/-) mice were able to down-regulate the Th1-dominated inflammatory mucosal immune response and/or induce an anti-inflammatory Th2/T regulatory response and thereby diminish the severity of colitis following treatment with acellular Bordetella pertussis vaccine. The acellular vaccine against B. pertussis, the causative agent of whooping cough, has been demonstrated to induce a Th2-mediated response in both man and mice. We therefore treated Galphai2(-/-) mice intraperitoneally with a three-component acellular B. pertussis vaccine. The treated Galphai2(-/-) mice showed significantly increased interleukin (IL)-10 production in intestinal tissue, associated with significantly reduced colitis and decreased mortality, compared to untreated Galphai2(-/-) mice. The attenuation of colitis in Galphai2(-/-) mice was due, at least partly, to the B. pertussis surface antigen filamentous haemagglutinin (FHA), which almost completely inhibited proliferation of CD4(+) T cells and stimulated apoptosis of activated CD4(+) T helper 1 cells. In conclusion, the three-component acellular B. pertussis vaccine containing filamentous haemagglutinin increases the production of IL-10 in the intestinal mucosa, induces apoptosis of activated Th1 cells and attenuates colitis in Galphai2(-/-) mice.

Quantitative measurement of cytokine mRNA in inflammatory bowel disease: relation to clinical and endoscopic activity and outcome

OBJECTIVE

The objective of this study was to quantitatively determine cytokine mRNA expression in inflammatory bowel disease under different clinical conditions including active disease, remission or an impaired response to a glucocorticoid (GC) therapy.

METHODS

Mucosal biopsies were taken from 33 patients with ulcerative colitis (UC), 21 patients with Crohn's disease (CD) and 11 controls. Peripheral blood mononuclear cells (PBMNC) were isolated from 24 CU patients, 18 CD patients and 11 controls. Cytokine-mRNA [interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-10, interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha)] expression was measured by quantitative reverse transcriptase-polymerase chain reaction in biopsies and PBMNC, and correlated to endoscopic findings, clinical activity and outcome after 6 months GC therapy.

RESULTS

IL-1beta, IL-6 and TNF-alpha were the largely dominating cytokines. In contrast to IL-1beta and TNF-alpha-, IL-6 expression was restricted to inflamed mucosa and correlated with the clinical activity and C-reactive protein levels in cases of pancolitis ulcerosa. TNF-alpha was elevated in CD even in endoscopic normal tissue. IL-2 and IFN-gamma were downregulated in PBMNC from CD and UC. No Th1 or Th2 specificity could be detected. Cytokine mRNA levels did not correlate with the response to a GC therapy.

CONCLUSION

IL-6 sharply distinguishes between inflamed and non-inflamed mucosa, and is therefore a suitable marker of intestinal inflammation. Its selective expression in the inflammatory site makes it an interesting target for future therapeutic strategies. TNF-alpha overexpression even in remission suggests a key role of this cytokine in CD pathogenesis and is possibly a feature that allows one to differentiate CD from UC.

Protein microarray analysis of disease activity in pediatric inflammatory bowel disease demonstrates elevated serum PLGF, IL-7, TGF-beta1, and IL-12p40 levels in Crohn's disease and ulcerative colitis patients in remission versus active disease

OBJECTIVES

Cytokines and growth factors play a major role in the dysregulated immune response in inflammatory bowel disease (IBD). We hypothesized that significant differences exist between the serum cytokine and growth factor profiles of pediatric IBD patients with active disease (AD) and those in remission, and that levels of some of these soluble mediators may be used to define regulators in IBD and determine disease activity.

METHODS

Eighty-eight consecutive patients with confirmed Crohn's disease (CD) and ulcerative colitis (UC) seen at the Duke Children's Hospital were prospectively enrolled and a serum sample was obtained. Data were recorded at the time of serum collection to calculate disease activity indices. The relative expression of 78 cytokines, growth factors, and soluble receptors was determined using proprietary antibody-based protein microarrays amplified by rolling circle amplification. SPSS 8 (SPSS Inc., Chicago, IL) was used to compare protein profiles for CD and UC patients in clinical remission (CR) versus AD.

RESULTS

Sixty-five CD patients and 23 UC patients were enrolled. Forty-one CD patients had available samples and PCDAI results. Twenty-two patients were in remission PCDAI < or = 12.5 (median 5), 19 patients had disease activity >15 (median 30). Univariate analysis revealed that PLGF, IL-7, IL-12p40, and TGF-beta1 cytokine levels were significantly elevated for patients in CR versus AD (p < 0.01). Twelve UC serum samples had Seo/Truelove Witt AI for analysis. Five patients were in remission by TW AI and Seo AI < or =110 and 7 patients had active mild-to-severe disease by TW and Seo AI >110. Only one cytokine, IL12p40, showed significance between CR versus AD (p < 0.02).

CONCLUSIONS

Surprisingly, we found no differences in circulating levels of proinflammatory cytokines but found that pediatric IBD patients in remission compared to those with AD had higher levels of specific circulating cytokines, including the regulatory cytokines IL-12p40 and TGF-beta1. It may be that these cytokines directly regulate intestinal inflammation in IBD or reflect the activity of T regulatory cells in negatively regulating the inflammatory response. Further studies will be needed to validate our results to define the molecular pathways involved in the intestinal immune response in man.

Potential role for TL1A, the new TNF-family member and potent costimulator of IFN-gamma, in mucosal inflammation

TNF can potentiate IFN-gamma production by activated T cells and other members of the TNF-superfamily play key roles in this effect. A newly discovered TNF-superfamily cytokine (TL1A) could also be involved in initiating or promoting the Th1 response by enhancing IFN-gamma production. The purpose of this study was to assess the role of recombinant TL1A on IFN-gamma production by cultured PBMC and lamina propria LPMC and to determine whether TL1A expression is altered in inflammatory bowel disease. IFN-gamma, but not IL-4 or IL-10 production by PBMC and LPL, was dose-dependently augmented by TL1A (or by activation of its receptor, death domain receptor 3 [DR3], with specific mAb) independently of, but in synergy with, IL-12 and IL-18. T cell activating stimuli induced expression of TL1A on the cell membrane (mb-TL1A) in a fraction of peripheral blood (PB) T cells. In the intestinal mucosa, a fraction of lamina propria (LP) T cells, especially CD4+ cells, constitutively expressed mb-TL1A, and the fraction increased in mucosal inflammation. A higher fraction of cells also express the TL1A receptor DR3 in ulcerative colitis and Crohn's disease. TL1A transcript was several times more abundant in RNA from mucosal biopsies taken from inflamed Crohn's disease lesions than in those taken from uninvolved areas. Expression of TL1A and its receptor DR3 by lamina propria mononuclear cells (LPMC) could have significant influence on the severity of mucosal inflammation.

Cigarette smoking and appendectomy are risk factors for extraintestinal manifestations in ulcerative colitis

OBJECTIVE

Two common factors, cigarette smoking and appendectomy, have been found to play a role in ulcerative colitis (UC). Data on their role in the development of extraintestinal manifestations (EIM) are scarce.

METHODS

The relationship between cigarette smoking, appendectomy, and EIM was examined in a prospective study involving 535 (M/F = 319/216) consecutive UC patients followed up for 18 yr. We considered the major EIM: seronegative spondyloarthropathy, pyoderma gangrenosum/erythema nodosum, acute anterior uveitis, and primary sclerosing cholangitis. We excluded patients with a history of EIM or those colectomized before study entry, ex-smokers, and those who started to smoke during the course of UC.

RESULTS

In UC patients, seronegative spondyloarthropathy and dermatologic complications were found increased in smokers (p < 0.0001; p = 0.001) or in subjects with appendectomy (p = 0.0003; p = 0.02), while acute anterior uveitis and primary sclerosing cholangitis did not differ. The Kaplan-Meier analysis showed 18-yr rates for EIM of 71% in smokers and 45% in nonsmokers (log-rank test, p = 0.0001), and of 85% in patients with appendectomy and 48% in those without (p = 0.0001). Cox proportional-hazard model showed that cigarette smoking and appendectomy are independent factors promoting EIM. In smokers with appendectomy the adjusted hazard ratio (3.197, 95% CI 1.529-6.684) was higher than in patients with appendectomy alone (2.617, 95% CI 1.542-4.442) or smoking alone (1.947, 95% CI 1.317-2.879).

CONCLUSIONS

In UC patients, appendectomy and cigarette smoking are prognostic factors for the development of EIM. The unfavorable effect of cigarette smoking on EIM is additive to that of appendectomy.

Sjogren's syndrome in association with Crohn's disease

Crohn's disease has many autoimmune extraintestinal manifestations, such as arthritis, polymyositis, and erythema nodosum. However, an association between Crohn's disease and Sjogren's syndrome, an autoimmune disease, has rarely been reported. We describe the fourth case of Sjogren's syndrome in association with Crohn's disease. The patient is a 43-year-old African-American female diagnosed with Crohn's disease in 1981. Twenty years later, she developed abdominal pain, arthralgias, and sicca symptoms. Further evaluation led to a diagnosis of Sjogren's syndrome. Sjogren's syndrome should be considered in patients with underlying Crohn's disease who develop a constellation of constitutional, joint, and sicca symptoms.

CD44 isoform expression on colonic epithelium mediates lamina propria lymphocyte adhesion and is controlled by Th1 and Th2 cytokines

BACKGROUND AND AIMS

CD44v6 and CD44v3 are expressed on the surface of colonic epithelial cells in ulcerative colitis to a much greater extent than in Crohn's disease. We investigated mediators that induce CD44v6 and CD44v3 expression on colonic epithelium and the potential role of CD44 in mediating leucocyte-epithelial adhesion.

DESIGN AND METHODS

HT-29 cells were exposed to a range of T-helper 1 and T-helper 2 cytokines. Flow cytometry was used to determine their effect on CD44 isoform expression. The adhesion of peripheral blood and lamina propria lymphocytes to HT-29 monolayers was assessed and the effect of induction and blocking of CD44 isoforms was investigated.

RESULTS

Treatment of HT-29 cells with IL-4 and IL-13 resulted in a two- to three-fold increase in membrane expression of CD44v6 and CD44v3 isoforms. This was inhibited by T-helper 1 cytokines and hydrocortisone (P < 0.001). IL-4 increased lymphocyte adhesion to HT-29 monolayers approximately two-fold (P < 0.01). This increased adhesion of both lamina propria leucocytes and peripheral blood lymphocytes was abolished by anti-CD44v6 monoclonal antibodies (P < 0.01 and P < 0.05, respectively).

CONCLUSION

IL-4 and IL-13 are potent inducers of CD44v6 and CD44v3 expression on colon epithelial cells. The reciprocal effects of T-helper 2 and T-helper 1 cytokines on CD44 isoform expression may explain the observed differences between ulcerative colitis and colonic Crohn's disease. We have identified increased adhesion between lymphocytes and colon epithelial cells caused by IL-4-induced CD44v6 expression. This may contribute to epithelial targeting of inflammation in ulcerative colitis.

Cytokine profile in colonic mucosa of ulcerative colitis correlates with disease activity and response to granulocytapheresis

OBJECTIVE

The aim of this study was to clarify the correlation between cytokine profile in colonic mucosa with disease activity and response to granulocytapheresis (GCAP) in patients with ulcerative colitis (UC), using a reliable, reproducible quantitative method.

METHODS

Colonoscopic biopsies of inflamed colonic mucosa (16 patients, 21 cases) and uninflamed colonic mucosa (25 patients, 33 cases) were obtained from UC patients. Messenger (m)RNA was extracted and subjected to realtime polymerase chain reaction for quantitative measurement of interleukin (IL)-12, interferon-gamma, tumor necrosis factor-alpha, IL-4, IL-8, and IL-18 mRNAs. In seven patients with high disease activity despite prednisolone (PSL) treatment (> or = 20 mg/day), one course of GCAP was conducted, and pre- and post-GCAP cytokine profiles were determined.

RESULTS

In inflamed colonic mucosa of UC patients, three cytokine profiles were observed: 1) high expression of interferon-gamma, tumor necrosis factor-alpha, and IL-4 mRNAs but low expression of IL-8 mRNA; 2) high expression of IL-8 mRNA and low expression of others; and 3) low expression of all cytokines examined. Inflamed colonic mucosa of patients with high disease activity showed the second pattern. Inflamed colonic mucosa of patients who were not treated with PSL and who had low disease activity showed the first pattern, whereas those on high-dose PSL exhibited the second pattern. IL-8 mRNA was significantly higher in inflamed UC samples than in uninflamed samples. GCAP was effective in five of seven PSL-resistant patients (71.4%). IL-8 was the only cytokine that correlated with effectiveness of GCAP. Compared with GCAP nonresponders, responders had significantly higher IL-8 mRNA before GCAP and showed marked reduction of IL-8 mRNA after GCAP.

CONCLUSIONS

IL-8 mRNA was significantly increased in inflamed mucosa of UC. Patients with high IL-8 mRNA expression in colonic mucosa despite PSL treatment were responsive to GCAP. Therefore, quantitative measurement of mucosal IL-8 mRNA may be useful in predicting the response to GCAP.

Anti-tumour necrosis factor alpha (infliximab) in the treatment of severe ulcerative colitis: result of an open study on 13 patients

BACKGROUND

Conventional treatment options for patients with severe steroid-refractory ulcerative colitis include intravenous cyclosporine, which is frequently burdened by toxicity, or colectomy. Preliminary data suggest a benefit from anti-tumour necrosis factor alpha (Infliximab) therapy in patients with steroid refractory ulcerative colitis.

AIM

To evaluate the efficacy of Infliximab in the treatment of severe ulcerative colitis refractory to conventional therapy

PATIENTS AND METHODS

A series of 13 patients with severe ulcerative colitis, refractory to therapy with methyl-prednisolone, 60 mg daily for seven or more days, were treated with a single intravenous infusion of Infliximab 5 mg/kg.

RESULTS AND CONCLUSIONS

Of these 13 patients, 10 (77%) had a clinical response to therapy defined by a clinical activity index 10 on two consecutive days. In 2 patients (15%) total colectomy was necessary on account of clinical worsening whilst one patient refused surgery and was lost to follow-up. All patients who responded showed very rapid clinical improvement, within 2 to 3 days of infusion. Infusion with Infliximab produced no significant adverse events. The mean time of follow-up was 10.1 months (range 5-12; during this time, 9 out of 10 patients (90%) maintained clinical remission and were able to discontinue corticosteroid therapy. Infliximab appears to be an effective agent for inducing long-standing remission in refractory patients with severe ulcerative colitis.

Cytokines and anti-cytokine biologicals in autoimmunity: present and future

The increasing understanding of the role of cytokines in autoimmunity, and the observation that tumour necrosis factor alpha (TNFalpha) is central to the inflammatory and destructive process common to several human autoimmune diseases, has led to a new generation of therapeutics, the TNFalpha blocking agents. In this article, we review the current knowledge of the role of cytokines in autoimmunity as unravelled by studies both in the laboratory and the clinic. In addition, we discuss future prospects of the anti-TNFalpha therapy that may involve combination therapy with other anti-cytokine or anti-T cell biologicals, or the use of small chemicals targeting molecules involved in TNFalpha production such as NF-kappaB and p38 MAPK. The future developments of anti-TNFalpha and anti-cytokine therapy in general will be interesting.

Evaluation of Th1, Th2 and immunosuppressive cytokine mRNA expression within the colonic mucosa of dogs with idiopathic lymphocytic-plasmacytic colitis

The objective of this study was to evaluate the expression of the immunoregulatory and pro-inflammatory cytokines interleukin (IL)-2, IL-4, IL-6, IL-12p35, IL-12p40, interferon-gamma (IFN-gamma), and tumour necrosis factor-alpha (TNF-alpha), and the expression of the predominantly immunosuppressive cytokines transforming growth factor-beta (TGF-beta) and IL-10 in canine idiopathic lymphocytic-plasmacytic colitis (LPC). Semi-quantitative reverse transcriptase-polymerase chain reactions were performed using specific primers on RNA isolated from the colonic mucosa of healthy dogs, dogs with clinical signs of large intestinal disease but normal histopathology of the colon, and dogs with LPC. Canine LPC was associated with over-expression of IL-2 compared to healthy colonic mucosa (p<0.01) and the mucosa of dogs with large intestinal diarrhoea but normal histopathology (p<0.05). Higher levels of TNF-alpha mRNA were also seen in LPC compared to healthy mucosa (p<0.05). These results indicate that LPC is associated with activation of CD4+ T-helper lymphocytes and increased production of T-helper-1-type cytokines.

Differential expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in ulcerative colitis and Crohn's disease

Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is selectively expressed in the endothelial cells of intestinal mucosa and gut-associated lymphoid tissue (GALT). Engagement of MAdCAM-1 to its ligand, integrin alpha4beta7, on lymphocytes is associated with the homing of gut-associated lymphocytes to normal gastrointestinal tract and inflammation sites. The present study was designed to elucidate differences between Crohn's disease (CrD) and ulcerative colitis (UC) from the expression patterns of MAdCAM-1. Samples were taken from 40 patients with CrD and 24 patients with UC at surgical resection. Using frozen sections, immunohistochemistry was performed for MAdCAM-1, E-selectin and CD34. MAdCAM-1+ venules were abundant in inflamed mucosa in both UC and CrD. In contrast, clear differences were noted between UC and CrD in the inflammatory area in the ulcer base, that is, MAdCAM-1+ venules were more abundant in CrD than in UC (P < 0.001), while E-selectin was expressed equally in these venules in both diseases. Furthermore, CrD was characterized by the occurrence of MAdCAM-1+ venules in deeper layers of the intestinal tissue, mainly in lymphoid aggregates. Our data indicated more extensive expression of MAdCAM-1 in CrD, which could contribute not only to mucosal inflammation, but also to transmural inflammation in CrD.

The proportion of Th1 cells, which prevail in gut mucosa, is decreased in inflammatory bowel syndrome

T lymphocytes and their cytokines have an important role in the regulation of immune responses in the gut and in the pathogenesis of intestinal inflammation such as in Crohn's disease. The aim of this study was to analyse the Th1/Th2 cytokine profile (IFN-gamma, IL-2, IL-4 and IL-10) in intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) in Crohn's disease (CD) and ulcerative colitis (UC) in relation to healthy controls (C). Colonic and ileal biopsy specimens were obtained from controls (n = 13) and patients with CD (n = 32). Colonic biopsies were obtained from patients with UC (n = 11). Intracytoplasmic IFN-gamma, IL-2, IL-4 and IL-10 were determined by flow cytometry after PMA-ionomycin stimulation in IEL and LPL. In colonic LPL, a significant proportional decrease of IFN-gamma and IL-2 producing CD3+ cells was observed in patients with CD and UC compared to controls. In ileal LPL, a similar tendency was found although differences were not significant. In IEL no differences in cytokine profiles could be observed. Flow cytometric analysis of intracytoplasmic cytokines at single cell level showed a proportional decrease of IFN-gamma and IL-2 producing T cells in colonic lamina propria in patients with inflammatory bowel disease.

The Crohn's disease-associated bacterial protein I2 is a novel enteric t cell superantigen

An aberrant T cell response to enteric bacteria is important in inflammatory bowel disease. However, the identity of relevant microbial antigens is unknown. Here, we report the presence of I2, a Crohn's disease-associated microbial gene, in the murine intestine. The I2 protein induced a proliferative and IL-10 response by CD4(+) T cells from unimmunized mice. The I2 response was dependent on MHC class II-mediated recognition but did not require antigen processing. Selective activation was observed for the TCR-Vbeta5 subpopulation. These findings indicate that the I2 protein is a new class of T cell superantigen and suggest that colonization by the I2 microorganism in susceptible hosts may provide a superantigenic stimulus pertinent to Crohn's disease pathogenesis.

B2 microglobulin: is it a reliable marker of activity in inflammatory bowel disease?

OBJECTIVES

The aims of this study were to investigate a possible positive correlation between B2-microglobulin (B2-M) serum levels and the severity and activity of inflammatory bowel disease (IBD); and to examine whether B2-M levels reflect IBD extent.

METHODS

We examined B2-M serum levels in 87 ulcerative colitis (UC) patients, 74 with Crohn's disease (CD) and 68 control subjects, using an enzymatic method. The reliability of the measuring method was assessed by evaluating serum B2-M in 18 patients suffering from chronic renal failure (CRF). The severity and activity of IBD was estimated using the van Hees Activity Index and the True-love-Witts criteria for CD and UC patients respectively. Endoscopic evaluation for UC patients was done according to Baron's et al. classification; Riley's et al. criteria were used for histological evaluation.

RESULTS

B2-M serum levels were significantly increased in all CD patients except those in remission. After 6 months treatment a second blood sample taken from CD patients with initially elevated B2-M levels proved to be compatible with CD severity at that time. Such a positive correlation was not assessed in UC patients; therefore, a second blood sample was considered unnecessary. Furthermore, CD patients with pancolitis, ileal-caecal, or small intestinal disease had higher B2-M levels than those with left-sided, anal, or perianal disease.

CONCLUSIONS

B2-M serum levels could prove to be a useful marker in assessing not only the activity, severity, and extent of CD but the treatment efficacy as well.

Identification of genes upregulated in the inflamed colonic lesions of Crohn's disease

To identify the molecular mechanism which primarily plays a role in the pathogenesis of Crohn's disease (CD) without prior hypothesis, differential display method was employed to detect differentially expressed genes between the inflamed and uninflamed colonic samples from one patient with CD. The mRNA levels of these genes were subsequently semi-quantitated in affected and unaffected tissues from six patients using reverse transcriptase polymerase chain reaction (RT-PCR). Six genes including long form FLICE inhibitory protein (FLIP(L)) were found to be consistently overexpressed in the inflamed colonic CD tissues. Immunohistochemical studies revealed that FLIP(L) expressing cells were lamina propria lymphocytes (LPLs). The present study suggested that overexpression of FLIP(L) in the LPLs may be involved in the pathogenesis of CD through defective activation-induced cell death. In addition, this study provided evidence for a possible role of several previously unsuspected genes in the pathogenesis of CD.

Selective resistance of mucosal T-cell activation to immunosuppression in Crohn's disease

BACKGROUND & AIMS

The inappropriately high state of T-cell activation found in Crohn's disease could be due to failure to respond to inhibitory signals. We tested the hypothesis that Crohn's disease mucosal T-cells are resistant to the immunosuppressive action of interleukin4.

PATIENTS

Patients with Crohn's disease, ulcerative colitis, and other malignant and non-malignant conditions undergoing bowel resection.

METHODS

The effect of interleukin-4 on lamina propria mononuclear cells from Crohn's disease, ulcerative colitis and control mucosa was assessed on various T-cell functions: interleukin-2-induced cytotoxicity, soluble interleukin-2 receptor and interleukin-2 production, and expression of mRNA for interleukin-2R and interferon-gamma.

RESULTS

Cytotoxicity of control and ulcerative colitis cells was markedly decreased by interleukin-4, whereas Crohn's disease cells failed to be inhibited. Addition of interleukin-4 to interleukin-2-stimulated cultures decreased soluble interleukin-2R production significantly less in Crohn's disease and ulcerative colitis than control cells. In the same cultures, residual levels of interleukin-2 were significantly increased in control and ulcerative colitis, but not Crohn's disease cultures. Finally, Crohn's disease cells were significantly more resistant to interleukin-4-mediated inhibition of spontaneous and interleukin-2-induced expression of interleukin-2Ralpha and interferon-gamma mRNA compared to control cells.

CONCLUSIONS

The effector function, receptor expression and cytokine production of Crohn's disease mucosal T-cells are resistant to interleukin4-mediated inhibition. Failure to respond to down-regulatory signals may contribute to persistent T-cell activation and chronicity of inflammation in Crohn's disease.

Distribution and phenotype of Epstein-Barr virus-infected cells in inflammatory bowel disease

Little is known about Epstein-Barr virus (EBV) infection of colon mucosa, particularly in inflammatory bowel diseases. Crohn's disease and ulcerative colitis are thought to differ in T-helper lymphocyte composition and cytokine secretion patterns. Some of the implicated cytokines are growth factors for EBV-infected cells. We examined colon mucosa for differences in the distribution and phenotype of EBV-infected cells. Colon tissues with Crohn's disease (n = 31) or ulcerative colitis (n = 25) and controls (n = 60) were characterized by in situ hybridization and immunohistology for six EBV gene products as indicators of latent and replicative EBV infection. The cells were additionally phenotyped by combined detection of the EBV transcripts and B- or T-cell antigens. B lymphocytes predominated as the site of latent EBV infection in the colon and were most numerous in ulcerative colitis. In active ulcerative colitis, EBV-positive lymphocytes accumulated under and within the epithelium and displayed evidence for replicative infection. The patterns of mucosal EBV gene expression indicate local impairment of virus-specific T-cell responses in active ulcerative colitis. Detection of EBV may help to discriminate between active ulcerative colitis and other inflammatory bowel diseases. Colon mucosa is a potential site of EBV replication and may be relevant for EBV transmission.

Mucosal cytokine production in radiation-induced proctosigmoiditis compared with inflammatory bowel disease

OBJECTIVE

We measured the mucosal levels of interleukin 1beta (IL-1beta), IL-2, IL-6, and IL-8 in affected segments of radiation-induced proctosigmoiditis and compared these with the levels in normal controls and inflammatory bowel disease (IBD) patients.

METHODS

Thirteen patients with histologically proven radiation proctosigmoiditis, 32 patients with active ulcerative colitis (UC), 35 patients with Crohn's disease, and 15 normal subjects undergoing routine colonoscopy were included in the study. All patients underwent colonoscopy and mucosal biopsies were obtained from both diseased and normal-appearing areas. Mucosal levels of IL-1beta, IL-2, IL-6, and IL-8 were determined by solid-phase enzyme-linked immunosorbent assay (ELISA) using the Quantikine method (R&D Systems, Minneapolis, MN). All the data were statistically analyzed using Student's t test.

RESULTS

The mucosal levels of IL-2, IL-6, and IL-8 were significantly higher in both diseased segments (5.62 +/- 0.13, 1.60 +/- 0.31, and 21.45 +/- 4.03 pg/ml, respectively) and normal-appearing segments (3.83 +/- 0.78, 1.36 +/- 0.34, and 13.45 +/- 3.18 pg/mg) in the radiation proctitis group compared to those of normal control subjects (1.74 +/- 0.23, 0.67 +/- 0.09, and 4.99 +/- 1.39 pg/mg). These differences were statistically significant (p < 0.05). In the UC group, IL-1beta, IL-6, and IL-8 levels in diseased segments were 4.98 +/- 0.53, 2.22 +/- 0.28, and 88.85 +/- 8.05 pg/mg, respectively. In Crohn's disease patients, IL-1beta, IL-6, and IL-8 levels were 5.45 +/- 0.93, 2.88 +/- 0.58, and 61.68 +/- 10.02 pg/mg, respectively. All these levels were significantly higher (p < 0.05) compared with IL-1beta, IL-6, and IL-8 levels from normal segments of IBD patients. Compared with the radiation proctitis patients, the levels of IL-6 and IL-8 were significantly higher in the IBD group.

CONCLUSIONS

The mucosal levels of IL-2, IL-6, and IL-8 were significantly higher in both diseased and normal segments of colon in patients with radiation proctitis, compared with normal controls. Only IL-1beta levels were significantly higher in diseased segments, compared with endoscopically normal-appearing segments in radiation proctitis. These results indicate that there is a similarity in the activation of mucosal cytokines between IBD and radiation proctosigmoiditis. This may partly explain the beneficial effects of similar topical and systemic agents such as steroids and mesalamine compounds when used in radiation-induced proctosigmoiditis.

Defining new pathogens and nonculturable infectious agents associated with inflammatory bowel disease

The causes of inflammatory bowel disease remain uncertain, but increasing evidence supports roles for two pathogenic processes: genetic susceptibility in the host and an aberrant host response to enteric bacteria. Here, we review studies showing that the pathogenesis of inflammatory bowel disease involves both bacterial agents and genetic susceptibilities. We discuss the roles of known and novel commensal intestinal bacteria in the pathogenesis of inflammatory bowel disease and the various recombinant approaches used to identify these pathogens.

Interleukin-6 and soluble interleukin-6 receptor in the colonic mucosa of inflammatory bowel disease

BACKGROUND

Interleukin-6 (IL-6) has multiple immunological effects on a wide variety of cells and tissues. The expression of IL-6 and IL-6 receptor (IL-6R) may be important to the pathogenesis of inflammatory bowel disease (IBD).

METHODS

In the present study, we examined whether mucosal IL-6 and soluble IL-6R were associated with the pathophysiology of IBD using the colonic mucosal specimens obtained from patients with IBD. Enzyme-linked immunosorbent assay was used to measure the levels of IL-6 and sIL-6R in organ cultures of mucosal tissues and in cell cultures of fractionated mucosal cells as well as in the serum. Expression of IL-6 and IL-6R was analysed by reverse transcription-polymerase chain reaction analysis using freshly isolated lamina propria mononuclear cells (LPMC).

RESULTS

The levels of IL-6 and sIL-6R in organ cultures were substantially elevated in patients with IBD, especially in those with histologically active inflammation. In contrast, considerably higher levels of sIL-6R were detected in patients with other types of colonic inflammation who were included as inflammatory controls, but elevation of IL-6 was less prominent in such patients. The positivity for expression of IL-6 and IL-6R mRNA in LPMC was in parallel with the results obtained in organ cultures. In cell cultures, mucosal macrophages were the main cell type producing both IL-6 and sIL-6R on a per cell basis and other cell fractions including colonic epithelial cells and lymphocytes produced substantially lower amounts of these molecules. The levels of IL-6 and sIL-6R in organ cultures, but not those in the serum, showed a significantly positive correlation with the degree of clinical disease activity in patients with IBD.

CONCLUSIONS

Enhanced IL-6/sIL-6R-mediated immune and inflammatory responses may be implicated, at least partly, in the continuation of intestinal inflammation in patients with IBD.

Characterization of cytokine expression in the rectal mucosa of ulcerative colitis: correlation with disease activity

OBJECTIVE

Mucosal inflammation in ulcerative colitis (UC) is presumed to be regulated by Th2-like cytokines. The aim of this study was to characterize local expression of various cytokines mRNA.

METHODS

Total RNA was extracted from rectal biopsy specimens in 61 patients with UC, 18 inflammatory controls, and 16 noninflammatory controls. Reverse-transcription polymerase chain reaction (RT-PCR) was used to determine mRNA expression of interleukin (IL)-2, interferon (IFN)-gamma, IL-4, IL-10, IL-13, and IL-15.

RESULTS

Expression of IL-10 was more frequent in UC (75.4%) than in noninflammatory controls (37.5%, p < 0.01). IL-4 was more frequently positive in UC (41%) than in inflammatory controls (5.6%, p < 0.01) and in noninflammatory controls (6.3%, p < 0.01). Positive expressions of IL-4 (66.7% vs 20.6%, p < 0.01) and IL-13 (63.0% vs 29.4%, p < 0.01) were higher in active UC than in inactive UC. The positive rate of IL-2, interferon (IFN)-gamma, and IL-15 expression showed no difference among the groups divided by clinical, endoscopic, and histological grade of inflammation.

CONCLUSIONS

These findings suggest that in active UC, IL-4 is pivotal, in combination with other Th2-like cytokines. In contrast, Th1-like cytokines and IL-15 bear no definite relation to local inflammation of UC.

Type 1 T-helper cell predominance in granulomas of Crohn's disease

OBJECTIVE

The pathogenesis of Crohn's disease (CD) is thought to be associated with production of several cytokines, especially type-1 cytokines. To elucidate the in situ cytokine profiles in CD, cytokine-containing cells were localized by immunohistochemistry, with special attention to noncaseating granulomas. The results were compared with those from studies of ulcerative colitis (UC).

METHODS

We adopted the biotin-streptavidin-peroxidase method on frozen sections obtained at surgery from patients with CD or UC, and we immunohistochemically examined the expression of several cytokines (interferon-gamma, interleukin-2, -4, -10, and -12).

RESULTS

In normal colonic tissue, expression of these cytokines was rare except for interleukin-4. In actively inflamed areas of CD, increased expression of all cytokines by mononuclear cells was observed. In contrast, granulomas in CD involved interferon-gamma+ lymphocytes and interleukin-12+ macrophage-lineage cells (epithelioid cells and multinucleated giant cells) but few interleukin-4+ or -10+ cells. Actively inflamed areas of UC also showed an increase in the number of cytokine-containing cells; however, quantitative analysis revealed that there was more expression of interferon-gamma and interleukin-12, and less of interleukin-10, in CD than in UC, indicating the presence of more type 1 T-helper cells in CD tissue than in UC.

CONCLUSIONS

The findings of the present study suggest that granulomas of CD are coupled with type 1 T-helper responses; these responses may contribute to the pathogenesis of this disease.

CD44v6 expression in inflammatory bowel disease is associated with activity detected by endoscopy and pathological features

AIMS

Overexpression of CD44v6 in colon crypt epithelial cells has been suggested to have diagnostic potential in differentiating ulcerative colitis from other forms of colon inflammation, including Crohn's disease. Our aim was to determine the value of CD44v6 expression in inflammatory bowel disease (IBD) and to look for possible associations between CD44v6 expression and activity of this disease.

METHODS AND RESULTS

CD44v6 expression was studied using immunohistochemical techniques in 100 surgical and endoscopic colon samples of ulcerative colitis (n = 71) and Crohn's disease (n = 29), and in every case disease activity was studied by endoscopy and microscopic examination. Fifty-five of 71 (77.5%) samples of ulcerative colitis showed monoclonal antibody 2F10 stained colon epithelium, as did 16 of 29 (55.2%) samples of Crohn's disease. CD44v6 was detected in 88.2% (15 of 17) of cases of IBD with severe disease activity and in 100% of eight cases of severe ulcerative colitis. Our study showed a strong association between CD44v6 expression and the activity of IBD (P = 0.007).

CONCLUSIONS

CD44v6 expression in IBD is significantly associated with activity detected by means of endoscopy and pathological features. Our data suggest that CD44v6 expression may have some usefulness in conjunction with other factors as a means of evaluating the disease activity. Moreover, CD44v6 expression was higher in ulcerative colitis than Crohn's disease (P = 0.02), although this does not confirm the utility of monoclonal antibody 2F10 in differential diagnosis between ulcerative colitis and Crohn's disease, as there was a notable percentage of positive samples of Crohn's disease.

Resistance of Crohn’s Disease T Cells to Multiple Apoptotic Signals Is Associated with a Bcl-2/Bax Mucosal Imbalance

Crohn’s disease (CD) is a condition characterized by excessive numbers of activated T cells in the mucosa. We investigated whether a defect in apoptosis could prolong T cell survival and contribute to their accumulation in the mucosa. Apoptotic, Bcl-2+, and Bax+ cells in tissue sections were detected by the TUNEL method and immunohistochemistry. T cell apoptosis was induced by IL-2 deprivation, Fas Ag ligation, and exposure to TNF-α and nitric oxide. TUNEL+ leukocytes were few in control, CD, and ulcerative colitis (UC) mucosa, with occasional CD68+ and myeloperoxidase+, but no CD45RO+, apoptotic cells. Compared with control and UC, CD T cells grew remarkably more in response to IL-2 and were significantly more resistant to IL-2 deprivation-induced apoptosis. CD T cells were also more resistant to Fas- and nitric oxide-mediated apoptosis, whereas TNF-α failed to induce cell death in all groups. Compared with control, CD mucosa contained similar numbers of Bcl-2+, but fewer Bax+, cells, while UC mucosa contained fewer Bcl-2+, but more Bax+, cells. Hence, the Bcl-2/Bax ratio was significantly higher in CD and lower in UC. These results indicate that CD may represent a disorder where the rate of T cell proliferation exceeds that of cell death. Insufficient T cell apoptosis may interfere with clonal deletion and maintenance of tolerance, and result in inappropriate T cell accumulation contributing to chronic inflammation.

The influence of cigarette smoking on cytokine levels in patients with inflammatory bowel disease

Anecdotal reports suggest that smoking may be beneficial for patients with inflammatory bowel disease (IBD) as nicotine may act through inflammatory mediators within the colonic mucosa. Furthermore, there is increasing evidence that cytokines play a pathologic role in IBD. Our aim was to determine the effects of cigarette smoking on cytokine levels in the colonic mucosa of patients with and without IBD. Mucosal biopsies were obtained from 10 patients with Crohn's disease (CD), 10 with ulcerative colitis (UC), and 10 healthy controls. Five of 10 patients in each of the three groups were smokers and five were nonsmokers. Concentrations of interleukin (IL)-1beta, IL-2, IL-6, and IL-8 were determined using enzyme-linked immunosorbent assay (ELISA). Cytokine levels of smokers were compared with nonsmokers in each group and with controls. Results were analyzed using the Mann-Whitney test; significance was set at p<0.05. The concentration of IL-8 was significantly higher in healthy controls who smoke compared with nonsmokers and significantly reduced in smokers with CD compared with nonsmokers with CD. Moreover, concentrations of IL-1beta and IL-8 were significantly reduced in smokers with UC compared with nonsmokers with UC. Smokers had significantly elevated levels of IL-8 in the colonic mucosa. Smokers with IBD had a significant reduction in cytokine levels; specifically, IL-1beta and IL-8 for patients with UC and IL-8 for patients with CD. Further studies are warranted to determine if this reduction in cytokine levels is histologically and clinically significant.