Background: Pyoderma gangrenosum (PG) is a chronic ulcerating skin condition that often occurs in association with inflammatory bowel disease. There have been a number of reports of PG responding to infliximab, a monoclonal antibody against tumour necrosis factor a. Aim: In the first randomised placebo controlled trial of any drug for the treatment of PG, we have studied the role of infliximab in this disorder. Subjects: Patients 18 years of age or older with a clinical diagnosis of PG were invited to take part. Methods: Patients were randomised to receive an infusion of infliximab at 5 mg/kg or placebo at week 0. Patients were then assessed at week 2 and non-responders were offered open labelled infliximab. The primary end point was clinical improvement at week 2, with secondary end points being remission and improvement at week 6. Results: Thirty patients were entered into the study. After randomisation, 13 patients received infliximab and 17 patients received placebo. At week 2, significantly more patients in the infliximab group had improved (46% (6/13)) compared with the placebo group (6% (1/17); p = 0.025). Overall, 29 patients received infliximab with 69% (20/29) demonstrating a beneficial clinical response. Remission rate at week 6 was 21% (6/29). There was no response in 31% (9/29) of patients.Conclusions: This study has demonstrated that infliximab at a dose of 5 mg/kg is superior to placebo in the treatment of PG. Open label treatment with infliximab also produced promising results. Infliximab treatment should be considered in patients with PG.

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Background The cause of pyoderma gangrenosum (PG) is unknown, but it is likely to be an immune-mediated disease because it is often associated with conditions such as inflammatory bowel disease and rheumatoid arthritis. T cells play an important role in these conditions and have been implicated in the pathogenesis of other skin diseases such as psoriasis.Objectives We examined the T-cell receptor repertoire in PG in order to test the hypothesis that if the T cells were responding to antigen, there would be expanded T-cell clones in the skin and the circulation of these patients. Patients and methods We studied five patients with PG and examined the T-cell receptor repertoire in cells taken from the peripheral blood and from biopsies of the ulcers, using complementarity determining region 3 spectratyping. Results We were able to demonstrate expanded clones in the peripheral blood lymphocyte population of each patient. Clonal expansions within the skin were found in four of the five patients. Most significantly, expanded clones that were shared between the blood and the skin were revealed in four of the five patients.Conclusions These findings imply that T cells play an integral role in the development of PG and suggest that T cells are trafficking to the skin under the influence of an antigenic stimulus.

Intestinal Ag exposure during neonatal life influences appropriate adult immune responses. To define the mechanisms shaping the T cell repertoire during this period, we examined T cell differentiation and receptor diversity in the intestine of human infants. Developmental phenotypes of intraepithelial and lamina propria intestinal T cells from infants aged 1 day to 2 years were assessed ex vivo by flow cytometry and in situ by triple-fluorescent immunohistochemistry. Gene recombination-specific enzymes were assessed by PCR. TCR β-chain V region gene diversity was determined by sequencing. Several different early lineage T cell populations were present neonatally: CD3+4−8− T cells were present at birth and numbers decreased during the neonatal period; CD3+4+8+ T cells were present in low numbers throughout infancy; and CD3+4+8− or CD3+4−8+ T cells increased with age. Very early lineage T cells, CD3−2−7+ and CD3−2+7+, were present neonatally, but were essentially absent at 1 year. Most lamina propria T cells differentiated rapidly after birth, but maturation of intraepithelial T cells took place over 1 year. Intestinal samples from infants less than 6 mo old contained transcripts of T early α and TdT, and 15 of 19 infant samples contained mRNA for RAG-1, some coexpressing RAG-2. TCR β-chain repertoires were polyclonal in infants. Immature T cells, pre-T cells, and genes involved in T cell recombination were found in the intestine during infancy. T cell differentiation occurs within the neonatal human intestine, and the TCR repertoire of these developing immature T cells is likely to be influenced by luminal Ags. Thus, mucosal T cell responsiveness to environmental Ag is shaped in situ during early life.

Patients will present with colorectal cancer despite having been invited to participate in the BCSP, with many having received a negative faecal occult blood test. This could be considered a high false negative rate.