Tumor necrosis factor alpha antibody (infliximab) therapy profoundly down-regulates the inflammation in Crohn's ileocolitis

Tumor Necrosis Factor and Its Blockade in Granulomatous Infections: Differential Modes of Action of Infliximab and Etanercept?

Tumor necrosis factor (TNF) is a critical component of both the antibacterially protective and the inflammatory responses against infections, particularly infections with intracellularly viable microorganisms. It is, therefore, not surprising that some treatment regimens that target TNF function have resulted in an increase in complications associated with infections due to such pathogens as Mycobacterium tuberculosis, Listeria monocytogenes, and Histoplasma capsulatum; organized granuloma formation is required to keep such infections under control. However, treatment with anti-TNF monoclonal antibodies (i.e., infliximab) has been associated with a higher incidence of granulomatous infections than has treatment with a TNF receptor (TNFR) p75 immunoglobulin G-fusion construct (i.e., etanercept). Three hypotheses concerning the mode of action of these 2 agents that might explain this difference are discussed here: differential induction of apoptosis or lysis in membrane TNF-expressing macrophages and T cells, differential inhibition of signaling via TNFRp55 and TNFRp75, and different net neutralizing capacities resulting from different pharmacologic properties.

Reconsidering Adjuvant Immunotherapy for Tuberculosis

BACKGROUND

Shortened regimens for treatment of pulmonary tuberculosis (TB) are urgently needed to facilitate its global eradication. Prolonged treatment is presently required to prevent relapse, which is thought to arise from persisting foci of semidormant infection contained within granulomas.

METHODS

The medical literature was reviewed to identify clinical trials of adjuvant TB immunotherapy, as well as other studies of the relationship between immune status and TB relapse or reactivation.

RESULTS

Four studies of therapeutic interferon indicated its inability to effectively augment the mycobactericidal capacity of lung macrophages. One randomized, placebo-controlled trial of therapeutic interleukin-2 found that it delayed the microbiologic response to treatment, whereas 2 controlled trials of anti-tumor necrosis factor (TNF) therapies (high-dose prednisolone and etanercept [a soluble TNF receptor]) found that these interventions significantly accelerated the response to treatment. Four retrospective studies were identified in which the response to TB therapy was accelerated and/or the relapse risk was reduced in persons with human immunodeficiency virus coinfection; one study reported that immune reconstitution syndrome due to use of antiretroviral therapy was associated with increased risk of relapse. Several studies indicated that granulomas may be efficiently targeted and disrupted by the anti-TNF antibody infliximab, apparently because of its ability to bind to cell-surface TNF and to induce apoptosis in TNF-expressing cells.

CONCLUSIONS

These findings support the hypothesis that the granulomatous host response to TB may paradoxically protect sequestered mycobacteria from administered anti-TB therapy and that treatment may be improved by therapeutic disruption of granulomas. Clinical trials to test this hypothesis are warranted.

Hyperresponsiveness of the mucosal barrier in Crohn's disease is not tumor necrosis factor-dependent

BACKGROUND

Crohn's disease (CD) is associated with gut barrier dysfunction. Besides the baseline barrier defect, a subgroup of patients also expresses an intestinal barrier hyperresponsiveness to nonsteroidal anti-inflammatory drugs. We studied whether reducing inflammation and restoring gut barrier dysfunction with anti-tumor necrosis factor (TNF) antibody treatment also antagonizes the permeability increase by oral nonsteroidal anti-inflammatory drug intake in patients with CD.

METHODS

Thirty-one healthy control subjects and 25 patients with active CD were studied. The 31 controls performed intestinal permeability testing for Cr-EDTA before (baseline) and after oral intake of indomethacin (50 + 75 mg). Twenty-five patients carried out a baseline and indomethacin-mediated permeability test before infliximab infusion. The patients repeated either the indomethacin test (12/25) or baseline and indomethacin tests (13/25), 1 month after this treatment. Intestinal permeability was studied by measurement of urinary excretion of Cr-EDTA after oral intake.

RESULTS

Increased whole gut permeation before treatment (3.16%; interquartile range [IQR], 2.92-5.72) was restored to normal values (2.47%; IQR, 1.97-2.78) by anti-TNF treatment. Indomethacin increased whole gut permeability significantly more in patients with CD (before anti-TNF: 6.50%; IQR, 4.84-10.38; after anti-TNF: 5.50%; IQR, 3.97-10.09) compared with the healthy subjects (4.66%; IQR, 3.51-5.64). Eleven of 25 patients (44%) had an abnormal whole gut permeability response to indomethacin before anti-TNF, and 9 of them remained hyperresponsive after infusion, despite clinical remission.

CONCLUSIONS

Although anti-TNF treatment suppresses inflammation and restores gut barrier function in patients with CD, it does not antagonize the barrier hyperresponsiveness to indomethacin. These data support the notion of an underlying intestinal mucosal barrier hyperresponsiveness in a subset of patients with CD, independent of inflammation.

In vivo demonstration of T lymphocyte migration and amelioration of ileitis in intestinal mucosa of SAMP1/Yit mice by the inhibition of MAdCAM-1

The aetiology of Crohn's disease (CD) remains unknown. Since SAMP1/Yit mice have been reported to develop CD-like spontaneous enteric inflammation, such mice have been studied as an animal model of CD. In this study, using this model we examined T lymphocyte migration in microvessels of intestinal mucosa in vivo and the expression of adhesion molecules by immunohistochemistry. Fluorescence-labelled T lymphocytes isolated from AKR/J (control) mice were injected into the tail veins of recipient mice, and T lymphocyte migration in the postcapillary venules of Peyer's patches, submucosal microvessels, and villus capillaries of the terminal ileum was monitored using an intravital microscope. Adhesion of T lymphocytes was significantly increased in 35 week old SAMP1/Yit mice compared with that in AKR/J or 15 week old SAMP1/Yit mice. Immunohistochemical study showed increased infiltration of CD4, CD8 and beta7-integrin-positive cells and increased expression of MAdCAM-1 and VCAM-1 in the terminal ileum of SAMP1/Yit mice. Antibodies against MAdCAM-1 and VCAM-1 significantly inhibited adhesion of T lymphocytes to microvessels of the terminal ileum, and anti-MAdCAM-1 antibody showed stronger suppressive effect than the anti-VCAM-1 antibody. Periodical administration of anti-MAdCAM-1 antibody twice a week for 7 weeks significantly ameliorated ileitis of SAMP1/Yit mice, but submucosal hypertrophy was not significantly suppressed. Anti-VCAM-1 antibody treatment failed to show significant resolution of ileitis. In addition, anti-MAdCAM-1 antibody treatment also attenuated established ileitis. The results demonstrate that, although MAdCAM-1 and VCAM-1 play an important role in T lymphocyte-endothelial cell interactions in SAMP1/Yit mice, MAdCAM-1 may be a more appropriate target for therapeutic modulation of chronic ileitis.

Tumor necrosis factor and granuloma biology: Explaining the differential infection risk of etanercept and infliximab

Several studies show that the risk of granulomatous infections following therapy with the anti-tumor necrosis factor (TNF) antibody infliximab is higher than after treatment with the soluble TNFRp75 immunoglobulin fusion construct etanercept. Therefore, despite sharing a common target, it is possible that the actual mode of action of the 2 biologicals differs in vivo. TNF is known to participate in the induction and maintenance of protective granulomas at multiple steps, and evidence supporting a differential inhibition of TNF bioactivity and signaling by the 2 drugs is discussed.

Very early treatment with infliximab in addition to methotrexate in early, poor-prognosis rheumatoid arthritis reduces magnetic resonance imaging evidence of synovitis and damage, with sustained benefit after infliximab withdrawal: results from a twelve-month randomized, double-blind, placebo-controlled trial

OBJECTIVE

Anti-tumor necrosis factor alpha agents are among the most effective therapies for rheumatoid arthritis (RA). However, their optimal use is yet to be determined. This 12-month double-blind study attempted remission induction using standard therapy with or without infliximab in patients with early, poor-prognosis RA. The primary end point was synovitis (measured by magnetic resonance imaging [MRI]). Clinical observations continued to 24 months.

METHODS

All patients had fewer than 12 months of symptoms. Assessments included full metrologic evaluation, laboratory tests, radiographs, functional evaluation using the Health Assessment Questionnaire (HAQ), and quality of life measurement using the RA Quality of Life (RAQoL) questionnaire. MRI was performed at 0, 4, 14, and 54 weeks; MR images were scored blindly. Patients received methotrexate (MTX) and were randomized to receive either infliximab or placebo for 12 months.

RESULTS

Twenty patients were recruited (mean age 52 years, mean symptom duration 6 months, mean C-reactive protein level 42 mg/liter, and 65% rheumatoid factor positive). At 1 year, all MRI scores were significantly better, with no new erosions in the infliximab plus MTX group; a greater percentage of infliximab plus MTX-treated patients fulfilled the American College of Rheumatology (ACR) 50% and 70% improvement criteria (78% versus 40% in the placebo plus MTX group and 67% versus 30%, respectively) and had a greater functional benefit (P < 0.05 for all comparisons). Importantly, at 1 year after stopping induction therapy, response was sustained in 70% of the patients in the infliximab plus MTX group, with a median Disease Activity Score in 28 joints (DAS28) of 2.05 (remission range). At 2 years, there were no significant between-group differences in the DAS28, ACR response, or radiographic scores, but differences in the HAQ and RAQoL scores were maintained (P < 0.05).

CONCLUSION

Remission induction with infliximab plus MTX provided a significant reduction in MRI evidence of synovitis and erosions at 1 year. At 2 years, functional and quality of life benefits were sustained, despite withdrawal of infliximab therapy. These data may have significant implications for the optimal use of expensive biologic therapies.

A randomized, double-blind, placebo-controlled trial of CDP571, a humanized monoclonal antibody to tumour necrosis factor-alpha, in patients with corticosteroid-dependent Crohn's disease

AIM

To evaluate CDP571, a humanized monoclonal antibody to tumour necrosis factor-alpha, for the treatment of corticosteroid-dependent Crohn's disease.

METHODS

Patients with corticosteroid-dependent Crohn's disease (use of prednisolone 15-40 mg/day or budesonide 9 mg/day for at least 8 weeks, a previous failed attempt to discontinue corticosteroids within 8 weeks, and Crohn's Disease Activity Index score 150 points or less) were enrolled in a 16-week, randomized, double-blind, placebo-controlled trial. The patients received intravenous CDP571 (20 mg/kg at week 0 and 10 mg/kg at week 8) or placebo. Corticosteroid therapy was decreased following a predefined schedule. The primary efficacy end-point was the percentage of patients with corticosteroid-sparing [i.e. no disease flare (Crohn's Disease Activity Index score > or =220 points) and no longer requiring corticosteroid therapy] at week 10. The major secondary efficacy end-point was corticosteroid-sparing at week 16.

RESULTS

Seventy-one patients received treatment. Corticosteroid-sparing was achieved by 19 of 39 (48.7%) CDP571 patients and 13 of 42 (40.6%) placebo patients (P = 0.452) at week 10, and by 18 of 39 (46.2%) CDP571 patients and seven of 32 (21.9%) placebo patients (P = 0.032) at week 16. CDP571 therapy was well-tolerated and the incidence of serious adverse events was similar to placebo.

CONCLUSIONS

The CDP571 was effective for corticosteroid-sparing at week 16 but not week 10, and was well-tolerated in patients with corticosteroid-dependent Crohn's disease.

Troglitazone, a PPAR-gamma activator prevents endothelial cell adhesion molecule expression and lymphocyte adhesion mediated by TNF-alpha

Background

Cytokine mediated induction of the mucosal addressin cell adhesion molecule-1(MAdCAM-1) expression is associated with the onset and progression of inflammatory bowel disease (IBD).

Results

Using western blotting and cell-based ELISA, we show in this study that troglitazone, an activator of the peroxisome proliferator-activated receptor-γ (PPAR-γ), widely used in the treatment of diabetes, has as well recently been highlighted as protective in models of inflammation and cancer. We found that troglitazone (10–40 μM), significantly reduced the TNF-α (1 ng/ml) mediated induction of endothelial MAdCAM-1 in a dose-dependent manner, achieving a 34.7% to 98.4% reduction in induced MAdCAM-1. Trogliazone (20μM) reduced TNF-α induced VCAM-1, ICAM-1 and E-selectin expression. Moreover, troglitazone significantly reduced α4β7-integrin dependent lymphocyte adhesion to TNF-α cultured endothelial cells.

Conclusions

These results suggest that PPAR-γ agonists like troglitazone may be useful in the clinical treatment of IBD.

Physiological basis for novel drug therapies used to treat the inflammatory bowel diseases. I. Immunology and therapeutic potential of antiadhesion molecule therapy in inflammatory bowel disease

Adhesion molecules regulate the influx of leukocytes in normal and inflamed gut. They are also involved in local lymphocyte stimulation and antigen presentation within the intestinal mucosa. In intestinal inflammation, many adhesion molecules are upregulated, but alpha4-integrins most likely hold a key position in directing leukocytes into the inflamed bowel wall. Therapeutic compounds directed against trafficking of leukocytes have been designed and are being developed as a novel class of drugs in the treatment of Crohn's disease and ulcerative colitis. This review deals with the immunological aspects of leukocyte trafficking focused on gut homing of T cells. Second, the changes in adhesion molecules and T cell trafficking during intestinal inflammation are discussed. Finally, we review the clinical data that have been gathered with respect to the therapeutic potential and the safety of antiadhesion molecule treatment. Antegren, or natalizumab, a humanized anti-alpha4 integrin IgG4 antibody, has been most extensively evaluated and may be close to registration. A more specific humanized alpha4beta7-integrin MLN-02 has shown preliminary clinical efficacy in ulcerative colitis, and both antergren and MLN-02 appear to be very safe. Trials with the anti-ICAM-1 antisense oligonucleotide ISIS-2302 in steroid refractory Crohn's disease have provided conflicting efficacy data. In the near future, some of these novel biological agents may prove valuable therapeutic tools in the management of refractory inflammatory bowel disease, although it is too early to define the patient population that will benefit most from these agents.

A distinct subset of chemokines dominates the mucosal chemokine response in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is characterised by intense mucosal recruitment of activated leukocytes. Chemokines determine inflammatory leukocyte recruitment and retention.

AIM

To compare expression of the entire chemokine family within colonic mucosa from IBD patients and uninflamed controls.

METHODS

A microarray of cDNAs, representing every member of this superfamily and their cognate receptors, was hybridised with probes derived from colonoscopic biopsies.

RESULTS

A distinct subset of chemokines, consisting of CXCLs 1-3 and 8 and CCL20, was upregulated in active colonic IBD, compared with uninflamed areas or tissue from controls. Increased expression of their cognate receptors, CXCR1, CXCR2 and CCR6, was confirmed by quantitative PCR and immunohistochemistry. An identical chemokine response was induced in Caco-2 cells by stimulation with interleukin (IL)-1beta, but not tumour necrosis factor-alpha (TNF-alpha). By contrast, IL-1beta and TNF-alpha were synergistic in an HT29 cell line and primary keratinocytes.

CONCLUSIONS

IL-1beta and TNF-alpha appear to be the pivotal mediators of a previously unidentified coordinated epithelial chemokine response that dominates the mucosal chemokine environment in inflamed IBD tissue.

Crohn's-like changes in the colon due to mycophenolate?

OBJECTIVE

Mycophenolate mofetil (MMF) is used for prevention of allograft rejection in kidney transplant patients. A subset of patients suffers from chronic diarrhoea of unknown origin. The aim of the study was to investigate the effect of MMF on the colonic mucosa.

MATERIALS AND METHODS

Colonic mucosal biopsies from 24 kidney transplant patients receiving MMF and presenting with chronic diarrhoea were analysed using routine stainings and immunohistochemistry for Ki67 and E-cadherin. Results were compared with a control group of 19 kidney transplant patients not receiving MMF. In all patients routine clinical and laboratory investigations were performed in order to explain the diarrhoea.

RESULTS

In 11 patients, the diarrhoea seemed to be of infectious origin. Furthermore, 19/24 of MMF-patients showed characteristic histological alterations of the mucosa that were Crohn's disease-like: discontinuous crypt architectural distortion, increased epithelial mucin secretion, mildly active inflammation and focal presence of dilated and inflamed crypts. Ki67 staining was abnormal in 6/24 MMF patients but also in 4/19 control patients. E-Cadherin staining was normal in most MMF and control patients.

CONCLUSIONS

Diarrhoea following MMF treatment is frequently infectious in origin and associated with morphological changes with a Crohn's-like pattern in the colonic mucosa in a subset of patients. MMF does not induce major alteration in the proliferative compartment of colonic epithelium. The diarrhoea is not associated with altered E-cadherin expression in the colonic epithelium.

Outcome of patients with active ankylosing spondylitis after two years of therapy with etanercept: Clinical and magnetic resonance imaging data

OBJECTIVE

To examine the long-term outcome of patients with active ankylosing spondylitis (AS) clinically and by magnetic resonance imaging (MRI) after continuous treatment with the tumor necrosis factor (TNF) receptor fusion protein etanercept over 2 years.

METHODS

Overall, 26 patients with active AS were treated with etanercept 25 mg twice daily subcutaneously, twice weekly with no concomitant disease-modifying antirheumatic drugs (DMARDs) or steroids. The clinical response was assessed by standardized parameters. Inflammatory spinal lesions were quantified by the ASspiMRI-a rating gadolinium-enhanced (T1-weighted gadolinium diethylenetriaminepentaacetic acid) and STIR MRI sequences. The primary outcome was a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) improvement > or =50% after 2 years of etanercept therapy compared with the baseline value of the study.

RESULTS

Overall, 21 (70%) of 30 patients completed year 2. In the intent-to-treat analysis, 54% of the patients showed a 50% improvement according to the BASDAI and a 40% improvement according to the Assessment in Ankylosing Spondylitis (ASAS) criteria. In the completer analysis, 9 (43%) of 21 patients were in partial remission according to ASAS criteria. Mean +/- SD BASDAI scores, which were elevated at baseline (6.3 +/- 1.6), remained low: 2.7 +/- 2.4 after 2 years compared with 2.6 +/- 2.2 at week 54. In accordance, all other clinical parameters showed sustained improvement during year 2. The majority of patients had no disease activity flares. MRI evaluation showed a 75% improvement of active spinal lesions, but minor spinal inflammation was still present in 64% of the patients after 2 years. There were 2 serious adverse events leading to discontinuation of etanercept.

CONCLUSION

The clinical efficacy and safety of etanercept in patients with active AS without simultaneous administration of DMARDs or steroids over 2 years of continuous treatment is confirmed. Spinal inflammation as depicted by MRI decreased significantly, but a few patients still had some spinal inflammation even after long-term anti-TNF therapy.

Role of endogenous and exogenous ligands for the peroxisome proliferators activated receptors alpha (PPAR-alpha) in the development of inflammatory bowel disease in mice

The peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors related to retinoid, steroid and thyroid hormone receptors. The aim of the present study was to examine the effects of endogenous and exogenous PPAR-alpha ligand on the development of experimental colitis. To address this question, we used an experimental model of colitis, induced by dinitrobenzene sulfonic acid (DNBS). When compared to DNBS-treated PPAR-alpha wild-type (WT) mice, DNBS-treated PPAR-alpha knockout mice (PPAR-alphaKO) mice experienced a higher rate of the extent and severity of the histological signs of colon injury. After administration of DNBS PPAR-alphaWT mice experienced hemorrhagic diarrhea, weight loss and large areas of necrosis in the mucosa of the colon were also observed. Neutrophil infiltration was associated with upregulation of ICAM-1. Immunohistochemistry for nitrotyrosine showed an intense staining in the inflamed colon. Absence of a functional PPAR-alpha gene in PPAR-alphaKO mice resulted in a significant augmentation of all the above-described parameters. On the contrary, the treatment of PPAR-alphaWT with Wy-14643 (1 mg/kg daily i.p) significantly reduced: (i) the degree of hemorrhagic diarrhea and weight loss, (ii) the degree of colon injury, (iii) the rise in MPO activity (mucosa), (iv) the increase in staining (immunohistochemistry) for nitrotyrosine, as well as (v) the upregulation of ICAM-1 caused by DNBS in the colon. In order to elucidate whether the protective effects of Wy-14643 is related to activation of the PPAR-alpha receptor, we also investigated the effect the of Wy-14643 treatment on PPAR-alpha-deficient mice. The absence of the PPAR-alpha receptor significantly abolished the protective effect of the PPAR-alpha agonist against DNBS-induced colitis. Thus, endogenous and exogenous PPAR-alpha ligands reduce the degree of colitis caused by DNBS. We propose that PPAR-alpha ligand may be useful in the treatment of inflammatory bowel disease.

Proinflammatory cytokines alter/reduce esophageal circular muscle contraction in experimental cat esophagitis

Cholinergic mechanisms are largely responsible for esophageal contraction in response to swallowing or to in vitro electrical field stimulation (EFS). After induction of experimental esophagitis by repeated acid perfusion, the responses to swallowing and to EFS were significantly reduced but contraction in response to ACh was not affected, suggesting that cholinergic mechanisms are damaged by acid perfusion but that myogenic mechanisms are not. Measurements of ACh release in response to EFS confirmed that release of ACh was reduced in esophagitis compared with normal controls. To examine factors contributing to this neuropathy, normal esophageal strips were incubated for 1-2 h with the proinflammatory cytokines IL-1beta (100 U/ml), IL-6 (1 ng/ml), or TNF-alpha (1 ng/ml). IL-1beta and IL-6 levels, measured by Western blot analysis, increased in esophagitis compared with normal circular muscle. IL-1beta and IL-6 reduced contraction in response to EFS (2-10 Hz, 0.2 ms) but did not affect ACh-induced contraction, suggesting that these cytokines inhibit ACh release without affecting myogenic contractile mechanisms. EFS-induced ACh release was significantly reduced in normal esophageal strips by incubation in IL-1beta or IL-6, suggesting that they may contribute to the contractility changes. TNF-alpha at 1 ng/ml, however, did not affect the response to ACh or to electrical stimulation but inhibited both at higher concentrations. TNF-alpha levels were low in normal muscle and did not increase with esophagitis. The data suggest that the proinflammatory cytokines IL-1beta and IL-6 contribute to reduced esophageal contraction by inhibiting release of ACh from myenteric neurons.

Lupus Nephritis Improvement After Anti‐tumor Necrosis Factor Alpha Monoclonal Antibody (Infliximab) Treatment for Crohn's Disease: A Case Report

Association between Crohn's disease (CD) and lupus nephritis is very rare and, to the best of our knowledge, it has been described only once. We report here a clinical case of CD occurred in a young woman 8 years after a diagnosis of lupus nephritis according to clinical, laboratory and histological criteria. CD was unresponsive to steroids and immunosuppressants and, therefore, the patient was treated with anti-tumour necrosis factor alpha monoclonal antibody (Infliximab). This therapy led to the remission of both CD (50% of Crohn's Disease Activity Index--CDAI--decrease) and lupus nephritis (disappearance of pyuria in absence of infection, significant increase of serum albumin and improvement of renal function tests). The immunological background of both diseases has to be taken into account to explain either the association of the two disorders or the therapeutic response. Moreover, this clinical case confirms and extends the concept that in patients with CD a more accurate detection of autoimmune associated disorders is required.

CDP571, a humanized anti-tumor necrosis factor-alpha monoclonal antibody in pediatric Crohn's disease

OBJECTIVES

The objectives of this study were to evaluate the safety, pharmacokinetics, and immunogenicity of CDP571 in pediatric patients with Crohn's disease.

METHODS

A single dose of CDP571, 10 mg/kg, was administered by infusion to pediatric patients (aged 6-17 years) with Crohn's disease in a 12-week open-label study. Adverse events were monitored during infusion and throughout the study. Plasma concentrations of CDP571 and standard clinical and laboratory values were assessed. Changes in disease activity were monitored using the Pediatric Crohn's Disease Activity Index (PCDAI).

RESULTS

Twenty patients were enrolled and stratified by age: 6 to 13 (n = 9) and 14 to 17 years (n = 11). Fourteen patients experienced adverse events, which were mainly mild or moderate in intensity. The plasma concentration profile was consistent with a half-life of approximately 2 weeks. At Week 4, 4 patients in the 6- to 13-year-old group and 2 patients in the 14- to 17-year-old group had detectable anti-CDP571 antibodies. By Week 2, 7 patients in the 6- to 13-year-old group and 6 patients in the 14- to 17-year-old group had responded to treatment (reduction in PCDAI score >10 points).

CONCLUSION

In conclusion, CDP571 was well tolerated among pediatric patients with Crohn's disease.

Infliximab for acute, not steroid-refractory ulcerative colitis: a randomized pilot study

OBJECTIVE

Therapeutic alternatives for patients with acute ulcerative colitis in whom steroids would usually be contraindicated are rare. The antibody to tumor necrosis factor alpha, infliximab, has shown to be effective in the treatment of steroid-refractory ulcerative colitis in pilot studies. We therefore evaluated whether infliximab can achieve remission in patients with acute ulcerative pancolitis who were not steroid-refractory.

METHODS AND DESIGN

Patients were eligible if they had acute disease with a modified Truelove and Witts activity score of more than 10 for at least 2 weeks and if they were currently not receiving immunomodulators or more than 10 mg/day prednisolone. Patients were randomly assigned to receive either three intravenous infusions of infliximab at 5 mg/kg (group A) or high-dose prednisolone (1.5 mg/kg body weight) daily for 2 weeks, followed by 1 mg/kg for 1 week, followed by a weekly reduction of 5 mg (group B). Therapy success was defined as clinical response in terms of a decrease of more than 5 points from the baseline score and to less than 10 points total after 3 weeks as well as after 13 weeks.

RESULTS

Thirteen patients (seven women, six men) were randomized (six for group A and seven for group B). The median baseline activity scores were 13.5 (12-18) in group A and 14.0 (11-18) in group B. Five of six patients in group A and six of seven patients in group B showed therapy success after 3 weeks as well as after 13 weeks.

CONCLUSIONS

Infliximab could be effective in the treatment of acute moderate or severe ulcerative colitis. The obtained data call for larger controlled trials.

Effect of antitumour necrosis factor-alpha therapy on bone turnover in patients with active Crohn's disease: a prospective study

BACKGROUND AND AIMS

Patients with Crohn's disease are at increased risk of osteoporosis. Disease activity and circulating proinflammatory cytokines are thought to play a role in this process. Infliximab, a chimaeric antitumour necrosis factor-alpha antibody is effective in the treatment of Crohn's disease. The aim of this study was to investigate the impact of treatment with infliximab on bone turnover in Crohn's disease patients.

METHODS

This was a prospective trial. Twenty-four patients with active Crohn's disease were treated with infliximab (5 mg/kg). Bone markers were assayed pre- and post-treatment. Bone formation was measured using serum bone-specific alkaline phosphatase and total osteocalcin and bone resorption using serum N-telopeptide cross-linked type 1 collagen.

RESULTS

Infliximab therapy caused a significant increase in both markers of bone formation in patients with active Crohn's disease. No significant change in the bone resorption marker serum N-telopeptide cross-linked type 1 was found.

CONCLUSION

Infliximab therapy had a significant beneficial effect on bone metabolism in patients with active Crohn's disease. These findings further support the theory that active ongoing inflammation and high levels of circulating cytokines play a pivotal role in the pathogenesis of bone loss in patients with Crohn's disease.

Extensive forearm deep venous thrombosis following a severe infliximab infusion reaction

Here we describe a patient with Crohn's disease who developed a severe infliximab infusion reaction (IIR), complicated 1 day later by severe swelling of the forearm and hand ipsilateral to the site of infliximab infusion. This proved to be extensive forearm deep venous thrombosis. The site of thrombosis and the chronological relationship with the IIR implicates a hypersensitivity to infliximab in the causation of the venous thrombosis in this case. With an increasing trend towards re-treating patients with known IIRs, clinicians should be aware of this potentially serious and previously unreported complication.

Safety of infliximab treatment in pediatric patients with inflammatory bowel disease

BACKGROUND

Infliximab appears to be efficacious in the treatment of pediatric Crohn disease (CD). There are few large-scale pediatric studies on the complications of infliximab therapy.

METHODS

A retrospective review of all infliximab infusions administered to IBD patients at a tertiary children's hospital was undertaken. Data was obtained from an infliximab infusion database maintained in the section of Pediatric Gastroenterology, pharmacy records and patient charts.

RESULTS

594 infusions were administered to 111 IBD patients (88 CD and 23 UC; 55 male and 56 female; ages 4 to 20 years; mean age, 13.4 years). The number of infusions ranged from 1 to 24 with a mean of 5.4/patient. Infusion reactions occurred in 8.1% of patients (seven early and two delayed) and in 1.5% of all infusions. Reactions occurred more frequently in female patients (14% versus 2%; P = 0.03). All reactions were mild and responded rapidly to treatment. Four patients had infections deemed unusual, including three cutaneous tinea infections and one case of shingles.

CONCLUSION

Infliximab is safe in pediatric IBD patients with a low incidence of generally mild reactions that respond rapidly to intervention. Infusion reactions are more common in female patients. Our patients had no serious infectious complications, although cutaneous tinea infection may represent a newly reported associated complication.

Autoantibody formation in patients with rheumatoid arthritis treated with anti-TNF alpha

BACKGROUND

Research on autoantibody formation in patients treated with TNF alpha inhibitors has produced contradictory results.

OBJECTIVE

To study the prevalence of autoantibodies in patients with rheumatoid arthritis treated with the TNF alpha inhibitor infliximab.

METHODS

53 patients (48 female, 11 male) treated with infliximab for rheumatoid arthritis were followed for autoantibody production before treatment and after 14, 30, and 54 weeks. Six patients treated with etanercept were studied for comparison. The analyses included antibodies against nuclear antigens (ANA), extractable nuclear antigens, double stranded (ds)DNA (by ELISA, IIF on Crithidia luciliae for IgM and IgG, and Farr assay), nucleosomes, cardiolipin, smooth muscle, mitochondria, proteinase 3, and myeloperoxidase antigens.

RESULTS

The number of patients treated with infliximab who developed antibodies against dsDNA of both IgG and IgM class (tested by IIF) increased significantly. The prevalence of patients positive for IgG class increased to 66% at 30 weeks and 45% at 54 weeks, and of IgM class to 85% and 70%, respectively. The titre and number of patients expressing antibodies against nucleosomes and ANA also increased significantly. The number of rheumatoid factor or anticardiolipin positive patients was stable and there was no increase in antibodies against the other antigens. A lupus-like syndrome was seen in one patient. No patient treated with etanercept developed any of these autoantibodies.

CONCLUSIONS

Patients treated with infliximab may develop anti-dsDNA antibodies of both IgM and IgG class, anti-nucleosome antibodies, and ANA, with a gradual increase until 30 weeks.

Increased production of granulocyte-macrophage colony-stimulating factor in Crohn's disease--a possible target for infliximab treatment

BACKGROUND

The presence of neutrophils among epithelial cells is one of the major features of the inflammation in Crohn's disease, and has been used to indicate disease activity. The survival of neutrophils outside the blood vessels is limited and their longevity is influenced by granulocyte-macrophage colony-stimulating factor (GM-CSF), which probably reduces neutrophil apoptosis.

OBJECTIVE

To study GM-CSF production in intestinal cell cultures from Crohn's disease patients before and after infliximab treatment.

PATIENTS

Colonic mucosal biopsies were obtained from 29 Crohn's disease patients before and after three infliximab infusions (5 mg/ml) and from ten healthy subjects.

METHODS

Biopsies were cultured in RPMI at high concentrations of interleukin-2 (IL-2) (2000 U/ml) and IL-4 (500 U/ml), but without antigen addition. GM-CSF content was analysed after 5 days culture and related to the Crohn's disease activity index (CDAI) and compared with the GM-CSF production from healthy subjects. Peripheral leucocyte count, C-reactive protein and the degree of mucosal inflammation, evaluated histologically, were determined. In-vitro T cell GM-CSF production was studied with/without addition of infliximab and after stimulation.

RESULTS

GM-CSF production was increased in Crohn's disease patients compared with healthy controls (P = 0.02) and correlated with the CDAI (Spearman rho = 0.65, P = 0.001). GM-CSF levels and mucosal histology score decreased (P = 0.007 and P = 0.01 respectively) after three infliximab infusions, as did the peripheral blood leucocyte count (P < 0.001). Infliximab inhibited in-vitro T cell GM-CSF production.

CONCLUSION

In-vitro cell culture production of GM-CSF was increased in Crohn's disease and related to inflammation, but decreased after infliximab treatment, probably because intestinal T cell GM-CSF production was reduced.

Infliximab therapy in 30 patients with refractory pediatric crohn disease with and without fistulas in The Netherlands

OBJECTIVE

The purpose of this study was to describe the clinical experience with the anti-tumor necrosis factor chimeric monoclonal antibody, infliximab, in pediatric patients with Crohn disease in The Netherlands.

DESIGN

Descriptive.

METHODS

Clinical response and adverse effects of infliximab were recorded for pediatric patients with Crohn disease treated from October 1992 to January 2003.

RESULTS

Thirty patients (aged 7-18 years) with refractory Crohn disease (with or without severe fistulas) were treated with infliximab. Patients were treated with up to 30 infusions. Mean follow-up was 25.3 months. A total of 212 infusions were administered. Thirteen patients had refractory Crohn disease without fistulas. Six patients showed good long-term response to infliximab treatment (defined as clinical index < or =10 points). Sixteen patients had refractory Crohn disease with draining fistulas. Nine showed good long-term response (closure or nonproductiveness of fistulas). One patient with metastatic Crohn disease in the skin had a good long-term response. Six patients developed an allergic reaction during infusion. In one patient, the allergic reaction occurred after an infliximab-free interval of 9 years. One patient died of sepsis.

CONCLUSIONS

Infliximab was an effective therapy in 53% of patients with refractory pediatric Crohn disease, with or without fistulas. Approximately half of the patients become unresponsive to infliximab therapy. Randomized controlled studies are mandatory to assess long-term efficacy and safety to define the optimal therapeutic strategy of infliximab therapy in children with Crohn disease.

Crohn's is not a 6-week disease: lifelong management of mild to moderate Crohn's disease

Crohn's disease is an idiopathic, chronic inflammatory disorder of the digestive tract with heterogeneous clinical presentations. Crohn's is currently not a curable disease, and patients are faced with a lifetime of recurrent disease flare-ups and remissions. Management strategies for Crohn's must therefore be targeted toward lifelong management, taking into consideration not only the short-term but also the long-term aspects of the disease. With this in mind, here we review the classifications and natural history of Crohn's disease and discuss possible predictive factors for the disease evolution in a patient. Here we also evaluate the current preferable treatment practices, based on scientifically valid research and collective clinical experience, for the management of mild to moderate Crohn's disease.

Medical management of postoperative recurrence in Crohn's disease

More than half of Crohn's disease patients require surgery during the course of their disease. Although endoscopic recurrence does not necessarily imply that patients have symptom recurrence, the high need for repeated surgery indicates that lesions gradually developing after surgical remission lead to fibrostenosis or other complications. Despite multiple clinical trials a clear medical strategy to prevent disease recurrence has not been identified. Future well designed collaborative trials with specified end points are needed to optimize clinical practice in the prevention of postoperative Crohn's disease recurrence.

Optimizing anti-TNF treatment in inflammatory bowel disease

Infliximab, the chimeric monoclonal immunoglobulin (Ig)G1 antibody to tumor necrosis factor (TNF) has changed our therapy of Crohn's disease. Infliximab is indicated in refractory luminal and fistulizing Crohn's disease. In patients with luminal disease, a single intravenous (i.v.) dose of 5 mg/kg is efficacious; in fistulizing disease, an i.v. loading therapy of 5 mg/kg at weeks 0, 2, and 6 is advocated. Because the majority of patients will relapse if not re-treated, a long-term strategy is necessary. The optimal long-term approach is systematic re-treatment with 5 mg/kg every 8 weeks. Episodic therapy on relapse also is possible but is less efficacious and frequently is associated with problems resulting from the formation of antibodies to infliximab (ATI). If treatment is episodic, maintenance therapy with immunosuppression (azathioprine [AZA]/6-mercaptopurine [6-MP] or methotrexate) is mandatory. Trial data suggest that systematic maintenance with 8 weekly doses of infliximab decreases the rate of complications, hospitalizations, and surgeries. These effects probably are achieved thanks to thorough healing of the bowel. Infliximab also is indicated in treating corticosteroid-dependent Crohn's disease and extraintestinal manifestations of Crohn's disease. There are no data yet that support its use as first-line therapy. The data in ulcerative colitis (UC) are conflicting and we should await the results of 2 large controlled trials (ACT1 and ACT2) to position infliximab in the treatment of UC. Other anti-TNF strategies have been less effective than infliximab in the treatment of IBD until now. The results with thalidomide are promising but much more research into small molecules inhibiting TNF and other proinflammatory cytokines is necessary. Safety problems with antibody treatment mainly concern immunogenicity leading to infusion reactions, loss of response, and serum sickness-like delayed infusion reactions. The rate of opportunistic infections is increased mainly in patients treated concomitantly with immunosuppression. Other adverse events associated with anti-TNF strategies are demyelinating disease and worsening of congestive heart failure. Malignancy rates in patients treated with anti-TNF strategies do not seem to be increased.

Demonstration of functional role of TECK/CCL25 in T lymphocyte-endothelium interaction in inflamed and uninflamed intestinal mucosa

It has recently been suggested that C-C chemokines may play a role in the organ-specific homing of lymphocytes, but there is not enough in vivo evidence in intestinal mucosa. The aim of this study was to examine whether thymus-expressed chemokine (TECK)/CCL25 and its ligand CCR9 are involved in T-lymphocyte interaction with microvessels of murine intestinal mucosa. T lymphocytes from the small intestine were fluorescence labeled, and their adhesion to mucosal microvessels was observed by intravital microscopy. Lamina proprial lymphocytes (LPL) and intraepithelial lymphocytes (IEL) adhered to both the small intestine and colon, and desensitization of CCR9 with TECK/CCL25 or anti-TECK/CCL25 antibody significantly inhibited these adhesions only in small intestine. At both sites, TNF-alpha significantly increased LPL adhesion but not IEL adhesion. Desensitization of CCR9 or anti-TECK/CCL25 antibody also attenuated the TNF-alpha-induced LPL adhesion in the small intestine. Increased expression of TECK/CCL25 by TNF-alpha was observed in the lamina propria of small intestine. TECK/CCL25 may thus play an important role in the adherence of mucosal lymphocytes to the microvessels of the small intestine but not the colon under uninflamed as well as inflamed conditions.

A porous defense: the leaky epithelial barrier in intestinal disease

A critical function of the intestinal mucosa is to form a barrier that separates luminal contents from the interstitium. This intestinal barrier is compromised in a number of intestinal diseases, most notably inflammatory bowel disease. In vitro studies have demonstrated that cytokines elaborated by immune cells can cause the mucosal barrier to become leaky; these cytokines are known to be increased in intestinal mucosa involved in inflammatory bowel disease. Detailed information describing the mechanisms by which altered cytokine signaling occurs is not available, but recent data implicate the cytoskeleton within epithelial cells as a critical regulator of the mucosal barrier under physiological and pathophysiological conditions. Using available data, we describe a model of intestinal disease where an initial insult to the epithelial barrier may trigger a self-amplifying cycle of immune activation, cytokine release, and further barrier dysfunction. This model is supported by the observation that pharmacological abrogation of cytokine signaling corrects both barrier defects and clinical disease in animal models and human patients, although such therapy clearly has multiple mechanisms. Other therapeutic targets that represent strategies to prevent or reverse disease processes are also considered. The overarching hypothesis is that modulation of the mucosal epithelial barrier plays a critical role in the initiation and propogation of inflammatory intestinal diseases.

Association between polymorphism in IgG Fc receptor IIIa coding gene and biological response to infliximab in Crohn's disease

AIM

To test the hypothesis of an association between polymorphism in FCGR3A (the gene coding for FcgammaRIIIa, which is expressed on macrophages and natural killer cells, is involved in antibody-dependent cell-mediated cytotoxicity and has recently been associated with a positive response to rituximab, a recombinant immunoglobulin G1 antibody used in non-Hodgkin's lymphomas) and response to infliximab in Crohn's disease.

METHODS

FCGR3A-158 polymorphism was determined using an allele-specific polymerase chain reaction assay in 200 Crohn's disease patients who had received infliximab for either refractory luminal (n = 142) or fistulizing (n = 58) Crohn's disease. Clinical and biological responses (according to C-reactive protein levels) were assessed in 200 and 145 patients, respectively.

RESULTS

There were 82.9% clinical responders in V/V patients vs. 72.7% in V/F and F/F patients (N.S.). Globally, the decrease in C-reactive protein was significantly higher in V/V patients than in F carriers (P = 0.0078). A biological response was observed in 100% of V/V patients, compared with 69.8% of F carriers (P = 0.0002; relative risk, 1.43; 95% confidence interval, 1.27-1.61). In the sub-group of patients with elevated C-reactive protein before treatment, the multivariate analysis selected the use of immunosuppressive drugs and FCGR3A genotype as independent factors influencing the clinical response to infliximab (P = 0.003).

CONCLUSION

Crohn's disease patients with FCGR3A-158 V/V genotype have a better biological and, possibly, clinical response to infliximab.

Tumour necrosis factor-alpha converting enzyme (TACE) activity in human colonic epithelial cells

Tumour necrosis factor (TNF)-alpha converting enzyme (TACE) releases biologically active, soluble TNF-alpha from transmembrane pro-TNF-alpha and has attracted interest as a specific therapeutic target in inflammatory bowel disease (IBD). Strong immunoreactivity for TACE protein was demonstrated recently in human colonic epithelium, but the function is unknown. We investigated if human colonic epithelial cells express functional TACE activity and how TACE expression is regulated in response to cytokine stimulation. TACE and TNF-alpha mRNA and protein expression were measured in HT-29 and DLD-1 colonic epithelial cells by reverse-transcription polymerase chain reaction, western blotting or enzyme-linked immunosorbent assay. Monocytic THP-1 cells served as positive control. Functional TACE activity was identified and quantified in detergent extracts of cell lines and freshly isolated colonocytes from 14 IBD patients and five controls by a hydrolysis assay using an oligopeptide spanning the cleavage site in pro-TNF-alpha. HT-29 and DLD-1 cells spontaneously expressed TACE mRNA and the active form of TACE protein at levels similar to those of monocytic cells. Functional TACE activity was demonstrated in all cell lines and in cells of controls or IBD patients irrespective of disease activity. TACE mRNA expression and functional activity remained unchanged in cell lines after stimulation with TNF-alpha despite clear induction of TNF-alpha mRNA expression and release of soluble TNF-alpha protein. The release of soluble TNF-alpha protein was almost completely abolished by CH4474, a synthetic TACE inhibitor. We conclude that functional TACE activity is constitutively expressed in human colonic epithelial cells and responsible for processing of the mature, soluble form of TNF-alpha in response to cytokine stimulation.

Etanercept therapy in patients with autoimmunity and hepatitis C

Accumulated data suggest that etanercept may be a therapeutic option in patients with hepatitis C and coexisting autoimmune disorders such as rheumatoid arthritis, psoriasis, psoriatic arthritis and ankylosing spondylitis. Additionally, etanercept may actually be of benefit, when used in combination with standard treatments, for hepatitis C.

Medical therapy for Crohn's disease strictures

Intestinal fibrostenosis is a frequent and debilitating complication of Crohn's disease (CD), not only resulting in small bowel obstruction, but eventually in repeated bowel resection and short bowel syndrome. Over one third of patients with CD have a clear stenosing disease phenotype, often in the absence of luminal inflammatory symptoms. Intestinal fibrosis is a consequence of chronic transmural inflammation in CD. As in other organs and tissues, phenotypic transformation and activation of resident mesenchymal cells, such as fibroblasts and smooth muscle cells, underlie fibrogenesis in the gut. The molecular mechanisms and growth factors involved in this process have not been identified. However, it is clear that inflammatory mediators may have effects on mesenchymal cells in the submucosa and the muscle layers that are profoundly different from their action on leukocytes or epithelial cells. Transforming growth factor-beta (TGF-beta), for instance, has profound anti-inflammatory activity in the mucosa and probably serves to keep physiologic inflammation at bay, but at the same time it appears to be driving the process of fibrosis in the deeper layers of the gut. Tumor necrosis factor, on the other hand, has antifibrotic bioactivity and pharmacologic inhibition of this cytokine carries a theoretical risk of enhanced stricture formation. Endoscopic management of intestinal strictures with balloon dilation is an accepted strategy to prevent or postpone repeated surgery, but careful patient selection is of paramount importance to ensure favorable long-term outcomes. Specific medical therapy aimed at preventing or reversing intestinal fibrosis is not yet available, but candidate molecules are emerging from research in the liver and in other organs.

Tumor necrosis factor-alpha antibody for induction of remission in Crohn's disease

BACKGROUND

Crohn's disease may be refractory to conventional treatments such as corticosteroids, enteral nutrition and immuno-suppressive agents. A number of patients with the disease may also become steroid-dependent leading to increased risk of developing steroid-related adverse effects. Recent studies suggest that TNF-a blocking agents may be effective in inducing remission in Crohn's disease.

OBJECTIVES

To conduct a systematic review to evaluate the effectiveness of TNF-a blocking agents in inducing remission in patients with active Crohn's disease.

SEARCH STRATEGY

We searched MEDLINE (1966-June 2003), EMBASE (1984-June 2003), the Cochrane Central Register of Controlled Trials from the Cochrane Library (Issue 2, 2003) and the IBD Review Group Specialized Trials Register. We hand-searched the articles cited in each publication obtained.

SELECTION CRITERIA

We included only randomised controlled trials in which patients with active Crohn's disease (defined by a validated Crohn's disease activity index) were randomly allocated to receive a TNF-a blocking agent in the treatment arm, or to receive placebo or another treatment in the comparison arm.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of the methodological quality of each trial were independently performed by two reviewers. Any disagreement among reviewers was resolved by consensus. Outcome measures reported in the primary studies included clinical remission, clinical response and changes in disease activity index.

MAIN RESULTS

Ten studies were identified of which 4 met the inclusion criteria. The included studies either differed in the type of TNF-a blocking agent used or in the way outcomes were assessed to such an extent that we considered it inappropriate to combine the data statistically. There is evidence from one randomised controlled trial that suggests that a single intravenous infusion of the monoclonal antibody cA2, infliximab, may be effective for induction of remission in Crohn's disease. There was no difference in response rates among infliximab doses of 5, 10 or 20 mg/kg. The results of two other trials suggested that CDP571, the genetically engineered human TNF monoclonal antibody, may also be effective in reducing disease activity index at 2 weeks after an infusion. We did not find any evidence to support the use of etanercept in Crohn's disease.

REVIEWER'S CONCLUSIONS

Evidence from one randomized controlled trial suggests that a single infusion of infliximab may be effective for induction of remission in Crohn's disease. Based on this study, we can recommend a dose of 5 mg/kg. There is also some evidence that CDP571 may be effective in inducing remission in Crohn's disease. We did not find any evidence that supports the use of etanercept in Crohn's disease. The period of follow up for the patients in these studies was probably too short to allow adequate assessment of recently reported serious adverse effects such as tuberculosis and lymphoma.

Biopsy assessment of drug efficacy in the gastrointestinal tract

When using biopsy pathology in clinical pharmacology to assess drug efficacy in the gastrointestinal tract, a number of questions must be answered: Is the biopsy necessary or more effective than macroscopic views by endoscopy? Can we extract maximal information from the specimen? Are there surrogate serum or other markers that give an overall measure of disease and/or improvement? Indeed, clinicopathological correlation is of paramount importance. If biopsy is to be used, it is important to utilize appropriate scoring systems. Many grading systems use continuous spectra, which are ordinal categorical variables and therefore a grading system of assigned 'numbers' which cannot be used in processes that require continuous variables such as linear regression. The use of grading vs a 'true' score with real numbers must be carefully considered, the site and number of biopsies must be precisely chosen and interobserver reproducibility of results evaluated before undertaking drug trials. Immunocytochemistry and in situ hybridization, however, can provide quantifiable molecular information related to mechanisms of drug action. The biopsy is of significant value as it is a true in vivo assessment if the above caveats are taken into account. However, further work is needed to determine sound histological criteria to assess the efficacy of drugs for use in gastrointestinal disease.

Disseminated tuberculosis, pulmonary aspergillosis and cutaneous herpes simplex infection in a patient with infliximab and methotrexate

CASE PRESENTATION

Despite chemoprophylaxis with isoniazid a 58-year-old Creole patient with mild rheumatoid arthritis developed disseminated tuberculosis, pulmonary aspergillosis and cutaneous herpes simplex infection during treatment with infliximab and methotrexate.

TREATMENT

The patient received antituberculous drugs (ethambutol, isoniazid, pyrazinamide, rifampicin), amphotericin B, flucytosine, and valaciclovir, along with prolonged intensive care treatment and mechanical ventilation.

CONCLUSIONS

The present case confirms that isoniazid prophylaxis (300 mg once daily, during 6 months) does not protect against the reactivation and dissemination of latent tuberculosis. It also shows that combined treatment with infliximab and methotrexate may induce severe immunosuppression with prolonged leukocytopenia and depressed cellular immunity, leading to multiple opportunistic infections. Extensive diagnostic testing, early start of antimicrobial therapy and enteral immunonutrition, and further infection prevention with selective decontamination of the digestive tract may have been the key to a good clinical outcome.

Evaluation of new therapies for inflammatory bowel disease

The pathophysiology of inflammatory bowel disease (IBD) is gradually being unravelled and new therapies are being developed to target the disturbed biological processes. This article outlines the clinical features of IBD, its current therapy and pathogenesis. The difficulties for clinical pharmacologists and gastroenterologists associated with designing, executing and interpreting clinical trials in IBD are then discussed. The final section reviews methods that can used to demonstrate the pharmacological actions of new treatments in patients with IBD. It is emphasized that proof of the therapeutic efficacy of a novel agent with a specific mechanism of action yields not only clinical benefit to patients with IBD, but also indicates the importance of the targeted biochemical pathway in the pathogenesis of the disease.

Complement activation in plasma before and after infliximab treatment in Crohn disease

BACKGROUND

Crohn disease is characterized by up-regulated intestinal inflammation mainly caused by increased tumour necrosis factor alpha (TNF-alpha) levels. However, the complement system (C) may also have a role in maintaining inflammation.

METHODS

Plasma from 26 patients with Crohn disease complicated by fistulizing ano-rectal disease was collected before and after three Infliximab infusions (5 mg kg(-1)).

RESULTS

Before treatment, the C3-activation capacities (C3-AC) in plasma from patients with Crohn disease were comparable with values obtained from healthy controls. The classical C pathway-mediated C3-AC, mannan-binding lectin C4-AC, leucocyte count, C-reactive protein concentration and Crohn Disease Activity Index decreased significantly 8 weeks after the first infusion of Infliximab (P < 0.04, Wilcoxon test).

CONCLUSIONS

Before treatment, all three C pathways were within the normal range in plasma from patients with Crohn disease; the decrease observed in the classical pathway-mediated C3-AC after treatment with Infliximab reflects a general down-regulation in immune activation.

The effect of etanercept and infliximab on the production of tumour necrosis factor alpha, interferon-gamma and GM-CSF in in vivo activated intestinal T lymphocyte cultures

BACKGROUND/AIMS

Infliximab (Ifx) is effective in the treatment of Crohn's disease (CD) and rheumatoid arthritis (RA), etanercept (Eta) in RA but not in CD. The mechanisms underlying these clinical differences are not fully understood, but this knowledge could be valuable to identify responders and develop new treatments. This study compares Eta and Ifx in vitro regarding transmembrane tumour necrosis factor alpha (tmb-TNF-alpha) expression and interferon-gamma (IFN-gamma), TNF-alpha and granulocyte macrophage colony stimulating factor (GM-CSF) production in intestinal T lymphocytes.

METHODS

T lymphocyte cultures were established from biopsies from 10 CD patients and three healthy controls. The cytokine production and the expression of tmb-TNF-alpha were measured in the presence of Ifx/Eta.

RESULTS

Eta and Ifx downregulated the production of IFN-gamma and GM-CSF in colonic T lymphocytes from CD patients and healthy controls. Both drugs bound tmb-TNF-alpha on activated T lymphocytes besides neutralising TNF-alpha, Eta less efficiently than Ifx (406 pg/ml (337-475); 133 pg/ml (119-147); p=0.004). TNF-alpha was detectable with the present assay in cell lines cultured in the presence of excess Eta.

CONCLUSIONS

We have established that Eta is just as efficient as Ifx in downregulating IFN-gamma and GM-CSF production in vitro and Eta bound to tmb-TNF-alpha. However, Eta bound the TNF-alpha molecule, important in CD, less efficiently than Ifx.

Infliximab for treatment of pyoderma gangrenosum associated with inflammatory bowel disease

OBJECTIVES

Pyoderma gangrenosum is an immune-mediated inflammatory condition characterized by ulcerative skin lesions affecting 1-2% of patients with inflammatory bowel disease (IBD). Treatment includes wound care, antibiotics, corticosteroids, and immunomodulators. However, response to therapy varies, and many patients with pyoderma gangrenosum have disease that is refractory to these agents. The aim of this study was to assess the response of medically refractory pyoderma gangrenosum to infliximab.

METHODS

This was a multicenter retrospective study of patients with IBD and medically refractory pyoderma gangrenosum treated with infliximab. Data collected included the following: baseline demographics; duration of IBD; history of bowel resection; duration of skin lesions; number, size, and location of pyoderma gangrenosum lesions; prior medications; dose and number of infliximab infusions; bowel activity before and after infliximab; pyoderma gangrenosum activity before and after infliximab therapy; time to response and time to healing of pyoderma gangrenosum lesions; recurrence of pyoderma gangrenosum after infliximab; corticosteroid taper; and adverse reactions to infliximab.

RESULTS

There were 13 patients with moderate to severe pyoderma gangrenosum and IBD treated with infliximab. All patients demonstrated complete healing of the skin lesions. Three patients had a complete response to induction infliximab therapy and did not require additional treatment. Ten patients responded to induction infliximab and have maintained pyoderma gangrenosum healing with infusions every 4-12 wk. All patients receiving corticosteroids were able to discontinue them completely after institution of infliximab treatment. Infliximab was well tolerated; the only treatment-related adverse events were sunburn in one patient and an infusion reaction in another.

CONCLUSIONS

Infliximab is a safe and effective treatment for IBD-associated pyoderma gangrenosum.

TNF-alpha neutralization ameliorates the severity of murine Crohn's-like ileitis by abrogation of intestinal epithelial cell apoptosis

Tumor necrosis factor alpha (TNF-alpha) is an important mediator of programmed cell death, and TNF-alpha blockade significantly improves disease severity in several inflammatory conditions, including Crohn's disease (CD), one of the idiopathic inflammatory bowel diseases. However, the precise mechanism(s) of action of anti-TNF-alpha therapy in CD remains poorly understood. SAMP1/YitFc mice develop a spontaneous ileitis with similarities to human CD in regard to histological features as well as response to conventional treatments. In this report, we tested the novel hypothesis that the beneficial effects of anti-TNF-alpha therapy in CD are mediated by a mechanism that involves down-regulation of intestinal epithelial cell (IEC) apoptosis. Similar to the efficacy of monoclonal anti-TNF-alpha antibodies in human CD, a single injection of a chimeric anti-murine TNF-alpha antibody into SAMP1/YitFc mice resulted in a marked suppression of intestinal inflammation and epithelial cell damage compared with mice injected with an isotype control antibody. These effects were associated with a significant reduction in apoptosis of freshly isolated IEC as assessed by propidium iodide staining and DNA laddering. In contrast, an increase in lamina propria mononuclear cell apoptosis was observed in anti-TNF-alpha-treated mice compared with control. These results were confirmed in vivo by using the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling-assay. In addition, neutralization of TNF-alpha reduced membrane bound FAS/CD95 expression in IEC from SAMP1/YitFc mice compared with control antibody. These data demonstrate a novel mechanism of action of anti-TNF-alpha therapy that involves homeostatic regulation of mucosal cell apoptosis, which results in the net decrease of chronic inflammation typically found in CD.

The signaling adaptors and pathways activated by TNF superfamily

Members of the TNF receptor superfamily play pivotal roles in numerous biological events in metazoan organisms. Ligand-mediated trimerization by corresponding homo- or heterotrimeric ligands, the TNF family ligands, causes recruitment of several intracellular adaptors, which activate multiple signal transduction pathways. While recruitment of death domain (DD) containing adaptors such as Fas associated death domain (FADD) and TNFR associated DD (TRADD) can lead to the activation of a signal transduction pathway that induces apoptosis, recruitment of TRAF family proteins can lead to the activation of transcription factors such as, NF-kappaB and JNK thereby promoting cell survival and differentiation as well as immune and inflammatory responses. Individual TNF receptors are expressed in different cell types and have a range of affinities for various intracellular adaptors, which provide tremendous signaling and biological specificities. In addition, numerous signaling modulators are involved in regulating activities of signal transduction pathways downstream of receptors in this superfamily. Most of the TNF receptor superfamily members as well as many of their signaling mediators, have been uncovered in the last two decades. However, much remains unknown about how individual signal transduction pathways are regulated upon activation by any particular TNF receptor, under physiological conditions.

Treatment of severe recalcitrant plaque psoriasis with single-dose intravenous tumour necrosis factor-alpha antibody (infliximab)

Infliximab is a chimeric anti-tumour necrosis factor-alpha antibody that has been demonstrated to have marked efficacy in the treatment of psoriasis. Seven patients with chronic plaque psoriasis were treated with single-dose intravenous infliximab (5 mg/kg), and the Psoriasis Area and Severity Index (PASI) and Dermatology Life Questionnaire Index (DLQI) were used as a measure of treatment efficacy. There was an average improvement in PASI scores of 69% at 2 weeks post infusion. There was an improvement in DLQI of 61%. Four of the seven patients were also seen at 10 weeks post infusion and the improvement in PASI and DLQI was sustained. All patients tolerated the initial infusion well without adverse events. The results indicate that single-dose infliximab is an effective and efficacious therapy for recalcitrant psoriasis and has a prolonged therapeutic effect.

Tumor necrosis factor alpha and apoptosis in Helicobacter pylori related progressive gastric damage: a possible mechanism of immune system involvement in epithelial turnover regulation

Helicobacter pylori (HP) related inflammation is mediated by tumour necrosis factor alpha (TNFalpha), which "in vitro" increases epithelial apoptosis in response to infection. In the early stages of HP gastritis, a raised epithelial apoptosis occurs; this phenomenon becomes less evident with progression towards intestinal metaplasia. Aim of our study was to analyze "in vivo" mucosal TNFalpha in relation to epithelial apoptosis in the progression of HP related histological damage. Antral biopsies from 20 HP positive patients were retrospectively studied: 10 with and 10 without intestinal metaplasia (IM and CG group respectively); samples of 10 dyspeptics with normal HP negative stomach (N) were used as control. The following parameters were evaluated by immunohistochemistry: 85 kDa caspase-cleaved fragment (p85) of human poly (ADP-ribose) polymerase (PARP) labelling index (LI) as marker of apoptosis and TNFalpha LI in stromal cells as marker of inflammatory response. Both epithelial apoptosis and mucosal TNFalpha expression were higher in chronic active gastritis compared to intestinal metaplasia and controls (PARP and TNFalpha LI: CG > IM > N; ANOVA & Student-Neumann-Keuls; p < 0.05 and p < 0.01, respectively). Pearson's coefficient showed a significant correlation between PARP and TNFalpha LI in IM and CG groups. Our data show that mucosal TNFalpha, similarly to what suggested "in vitro", may be related "in vivo" to epithelial apoptosis thus suggesting a possible mechanism for immune system involvement in the control of gastric epithelial turnover.

Infliximab as disease-modifying therapy

Recent insights in the pathophysiology of Crohn's disease have revealed that tumour necrosis factor (TNF) plays a pivotal role in mucosal inflammation. Infliximab is a chimeric anti-TNF monoclonal antibody with potent anti-inflammatory effects, probably based on apoptosis of inflammatory cells. Numerous controlled trials have demonstrated efficacy in both active and fistulating Crohn's disease. Appropriate indications for using infliximab and growing experience with safety aspects have made this treatment a highly valuable tool in the management of Crohn's disease.

Transfection of IL-10 expression vectors into endothelial cultures attenuates alpha4beta7-dependent lymphocyte adhesion mediated by MAdCAM-1

BACKGROUND

Enhanced expression of MAdCAM-1 (mucosal addressin cell adhesion molecule-1) is associated with the onset and progression of inflammatory bowel disease. The clinical significance of elevated MAdCAM-1 expression is supported by studies showing that immunoneutralization of MAdCAM-1, or its ligands reduce inflammation and mucosal damage in models of colitis. Interleukin-10 (IL-10) is an endogenous anti-inflammatory and immunomodulatory cytokine that has been shown to prevent inflammation and injury in several animal studies, however clinical IL-10 treatment remains insufficient because of difficulties in the route of IL-10 administration and its biological half-life. Here, we examined the ability of introducing an IL-10 expression vector into endothelial cultures to reduce responses to a proinflammatory cytokine, TNF-alpha

METHODS

A human IL-10 expression vector was transfected into high endothelial venular ('HEV') cells (SVEC4-10); we then examined TNF-alpha induced lymphocyte adhesion to lymphatic endothelial cells and TNF-alpha induced expression of MAdCAM-1 and compared these responses to control monolayers.

RESULTS

Transfection of the IL-10 vector into endothelial cultures significantly reduced TNF-alpha induced, MAdCAM-1 dependent lymphocyte adhesion (compared to non-transfected cells). IL-10 transfected endothelial cells expressed less than half (46 +/- 6.6%) of the MAdCAM-1 induced by TNF-alpha (set as 100%) in non-transfected (control) cells.

CONCLUSION

Our results suggest that gene therapy of the gut microvasculature with IL-10 vectors may be useful in the clinical treatment of IBD.

Crohn's disease: step up or top down therapy

The concept of a 'step-up' or 'top-down' approach to the treatment of Crohn's disease has evolved from the impact of novel anti-TNF (anti-tumour necrosis factor) therapies that have been effective for patients who are refractory to other medical treatments. In addition, the potential to produce mucosal healing with anti-TNF treatments without the well-recognized systemic complications of glucocorticoid therapy has created debate as to whether earlier, more aggressive, therapies should be advocated. This controversy arises at a time when the concept of sequential therapy to induce and maintain remissions for Crohn's disease has begun to be accepted and precedes our ability to define the concept of disease modification or predict the natural history of Crohn's disease based upon clinical, pathological, molecular orgenetic criteria. Evidence for therapeutic efficacy in Crohn's disease is presented as a prologue to considerations necessary to determine the benefits and risks of early aggressive treatment versus sequential approaches based upon disease severity.

Pharmacodynamic and pharmacokinetic response to anti-tumor necrosis factor-alpha monoclonal antibody (infliximab) treatment of moderate to severe psoriasis vulgaris

OBJECTIVE

Infliximab monotherapy provided a rapid and high degree of clinical benefit in patients with moderate to severe psoriasis in a previously conducted trial. Herein we describe the pharmacodynamic and pharmacokinetic results observed in this clinical trial.

METHODS

Patients with psoriasis received 5 or 10 mg/kg of infliximab or placebo at weeks 0, 2, and 6. Immunohistochemical analysis of lesional (weeks 0, 2, 10) and nonlesional (week 0) biopsies was conducted. Median infliximab half-life and peak serum concentrations over time were calculated.

RESULTS

Infliximab immunotherapy resulted in rapid and dramatic decreases in epidermal inflammation and normalization of keratinocyte differentiation in psoriatic plaques; these changes preceded maximal clinical response. Infliximab concentrations were maintained above the detection limit (0.1 mg/mL) in the majority of patients through week 14.

CONCLUSION

The clinical and immunohistologic data demonstrate a pivotal role for tumor necrosis factor-alpha in the pathogenesis of psoriasis and support further development of drugs targeting tumor necrosis factor-alpha.