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BACKGROUND AND AIMS: The widespread use of anti-tumour necrosis factor alpha antibody (Infliximab) in Crohn's disease (CD) raises concerns about a possible cancer risk in the long term. In a matched pair study, we assessed whether Infliximab is associated with an increased risk of neoplasia. METHODS: In a multicentre matched pair study, 404 CD patients treated with Infliximab (CD-IFX) were matched with 404 CD patients who had never received Infliximab (CD-C). Cases and controls were matched for sex, age (+/-5 years), site of CD, age at diagnosis (+/-5 years), immunosuppressant use, and follow up. New diagnoses of neoplasia from April 1999 to October 2004 were recorded. RESULTS: Among the 404 CD-IFX, neoplasia was diagnosed in nine patients (2.22%) while among the 404 CD-C, seven patients developed neoplasia (1.73%) (odds ratio 1.33 (95% confidence interval 0.46-3.84); p=0.40). The survival curve adjusted for patient year of follow up showed no differences between CD-IFX and CD-C (p=0.90; log rank test). In the CD-IFX group, there was one cholangiocarcinoma, three breast cancers, one skin cancer, one leukaemia, one laryngeal cancer, and two anal carcinomas. Among the 7/404 (1.73%) CD-C, there were three intestinal adenocarcinomas (two caecum, one rectum), one basalioma, one spinalioma, one non-Hodgkin's lymphoma, and one breast cancer. Age at diagnosis of neoplasia did not differ between groups (CD-IFX v CD-C: median 50 (range 40-70 years) v 45 (27-72); p=0.50). CONCLUSION: In our multicentre matched pair study, the frequency of a new diagnosis of neoplasia in CD patients treated with Infliximab was comparable with CD patients who had never received Infliximab.

Background - Antineutrophil cytoplasmic antibodies (ANCAs) from patients with vasculitidis can induce neutrophils to release oxygen radicals in vitro. ANCAs with a perinuclear pattern of immunofluorescence are found in most patients with ulcerative colitis, but several findings are against ANCAs having a pathogenetic role in this disease. Aims - To evaluate the influence of ANCAs associated with ulcerative colitis on the respiratory burst activity of neutrophils. Patients - Serum samples were obtained from 14 patients with ulcerative colitis, seven of whom showed positivity for p-ANCAs, three patients with vasculitidis, two with positivity for p-ANCAs, and one for c-ANCAs, and seven healthy volunteers. Methods - A positive ANCA serology was determined with a standard indirect immunofluroescence assay. Purified immunoglobulins (IgGs) were prepared from serum samples by DEAE-Affigel blue chromatography. Human neutrophils were prepared by dextran-Ficoll-Hypaque separation. Superoxide anion (O2-. generation was measured by following the superoxide dismutase inhibitable reduction of ferricytochrome. Results - There were no significant differences among samples from ulcerative colitis IgG p-ANCA positive, ulcerative colitis IgG p-ANCA negative patients, and controls on O2-6. production, whereas ANCA positive IgG from vasculitidis significantly enhanced O2-. release (p < 0.001). Conclusions - p-ANCAs associated with ulcerative colitis have no effect on the respiratory burst activity of normal human neutrophils in vitro. These results reinforce the hypotheses that ANCAs are unlikely to contribute to the pathogenesis of ulcerative colitis.

Background: “Probiotic” bacteria are effective in treating some inflammatory bowel diseases. However which bacteria confer benefit and mechanisms of action remain poorly defined. Dendritic cells, which are pivotal in early bacterial recognition, tolerance induction, and shaping of T cell responses, may be central in mediating the effects of these bacteria. Aims: To assess effects of different probiotic bacteria on dendritic cell function. Methods: Human intestinal lamina propria mononuclear cells, whole blood, or an enriched blood dendritic cell population were cultured with cell wall components of the eight bacterial strains in the probiotic preparation VSL#3 (four lactobacilli, three bifidobacteria, and one streptococcal strains). Dendritic cells were identified and changes in dendritic cell maturation/costimulatory markers and cytokine production in response to probiotic bacteria were analysed by multicolour flow cytometry, in addition to subsequent effects on T cell polarisation. Results: VSL#3 was a potent inducer of IL-10 by dendritic cells from blood and intestinal tissue, and inhibited generation of Th1 cells. Individual strains within VSL#3 displayed distinct immunomodulatory effects on dendritic cells; the most marked anti-inflammatory effects were produced by bifidobacteria strains which upregulated IL-10 production by dendritic cells, decreased expression of the costimulatory molecule CD80, and decreased interferon-γ production by T cells. VSL#3 diminished proinflammatory effects of LPS by decreasing LPS induced production of IL-12 while maintaining IL-10 production. Conclusions: Probiotic bacteria differ in their immunomodulatory activity and influence polarisation of immune responses at the earliest stage of antigen presentation by dendritic cells.