John A. Walker-Smith

Tumor necrosis factor α-producing cells in the intestinal mucosa of children with inflammatory bowel disease

Abstract Background/Aims: Cytokines are thought to be important in mediating tissue damage in inflammatory bowel disease (IBD). Many of the in vivo activities of tumor necrosis factor α (TNF-α) match the changes found in IBD, but its importance is controversial. Methods: A sensitive, reverse hemolytic plaque assay was used to determine the frequency of TNF-α secreting cells isolated from mucosal biopsy specimens of children with Crohns disease or ulcerative colitis (UC) and non-IBD controls before and after medical treatment. Results: Frequency of TNF-α secreting cells was significantly increased in biopsy specimens from children with mild, nonspecific inflammation compared with those with histologically normal intestine. Frequency did not increase in UC compared with children with nonspecific inflammation but was significantly greater in Crohns disease than in UC. After treatment, the frequency of TNF-α secreting cells was reduced in patients receiving cyclosporin A, not reduced in patients with steroids or enteral nutrition, and not changed with treatment in UC. Conclusions: TNF-α secreting cells are increased in the mucosa of inflamed intestine, regardless of pathogenesis. In patients with IBD, higher levels are seen in Crohns disease than in UC, probably reflecting the extensive T-cell activation in Crohns disease. No relation existed between histological healing and the frequency of TNF-α-secreting cells.

Retraction of an interpretation

This statement refers to the Early Report “Ileal-lymphoidnodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children”, published in The Lancet in 1998. It is made by 10 of the 12 original authors who could be contacted. It should be noted that this statement does not necessarily reflect the views of the other co-authors. The main thrust of this paper was the first description of an unexpected intestinal lesion in the children reported. Further evidence has been forthcoming in studies from the Royal Free Centre for Paediatric Gastroenterology and other groups to support and extend these findings. While much uncertainty remains about the nature of these changes, we believe it important that such work continues, as autistic children can potentially be helped by recognition and treatment of gastrointestinal problems. We wish to make it clear that in this paper no causal link was established between MMR vaccine and autism as the data were insufficient. However, the possibility of such a link was raised and consequent events have had major implications for public health. In view of this, we consider now is the appropriate time that we should together formally retract the interpretation placed upon these findings in the paper, according to precedent. We were unable to contact John Linnell.

Reduced transforming growth factor-β1-producing T cells in the duodenal mucosa of children with food allergy

Infant food allergies are increasing, and many breast‐fed infants now sensitize to maternally‐ingested antigens. As low‐dose oral tolerance requires generation of suppressor lymphocytes producing TGF‐β1 (Th3 cells), we studied these cells in duodenal biopsies after diagnostic endoscopy. Spontaneous production of Th1, Th2 and Th3 cytokines by duodenal lymphocytes was studied using flow cytometry in 20 children with no eventual clinico‐pathological diagnosis (controls), 30 children with multiple food allergy, nine with celiac disease and six with inflammatory enteropathies. Immunohistochemistry and in situ hybridization were used to localize TGF‐β1 protein and mRNA in matched biopsies. We found no significant Th1/Th2 skewing amongst mucosal lymphocytes in allergic children compared to controls, although celiac and inflammatory enteropathy patients showed increased Th1 responses. By contrast, the allergic children showed reduction of TGF‐β1+ lymphocytes in both epithelial and lamina propria compartments. Reduction of TGF‐β1 expression was also seen in mononuclear cells and epithelium in food allergy by immunohistochemistry and in situ hybridization. The dominant mucosal abnormality in food allergic children was, thus, not Th2 deviation but impaired generation of Th3 cells. As generation of these cells requires innate immune response to enteric bacteria, we suggest that changing infectious exposures may inhibit primary establishment of basic oral tolerance mechanisms.

Protracted diarrhoea of infancy: evidence in support of an autoimmune variant.

Circulating autoantibodies to enterocytes were detected by indirect immunofluorescence in 14 out of 25 patients with idiopathic protracted diarrhoea of infancy. Similar specificities were not found in 50 control children with nongastroenterological disorders. The immunofluorescence pattern was more accentuated on the apical border of mature enterocytes. Enterocyte autoantibodies were mainly of IgG class (13/14), but 11 sera were positive for IgM and IgA classes, and five out of 14 positive sera also had the ability to fix complement. Absorption of sera positive for autoantibodies with an IgA coupled immunoabsorbent did not modify the intensity of the staining, indicating that these antibodies were not directed against secretory IgA. High titres and the complement fixing ability of enterocyte autoantibodies indicated a poorer prognosis despite the use of immunosuppressive drugs. Organ specific and non-organ specific autoimmune diseases or corresponding autoantibodies or both were often found in children with enterocyte autoantibodies and their family. These data show the existence of an autoimmune variant of protracted diarrhoea of infancy, despite the rare occurrence of autoimmune diseases in childhood.

The Frequency of Cells Secreting Interferon-|[gamma]| and Interleukin-4, -5, and -10 in the Blood and Duodenal Mucosa of Children with Cow's Milk Hypersensitivity

Enzyme-linked immunoabsorbant spots (ELISPOTs) have been used to analyze the frequency of cells spontaneously secreting interferon-γ (INF-γ), IL-4, IL-5, or IL-10 in mononuclear cells isolated from the blood of children with cows milk-sensitive enteropathy (CMSE), cows milk allergy (CMA), and age-matched controls. In addition, cytokine profiles of duodenal lamina propria lymphocytes were compared in patients with CMSE and control subjects. In blood, spontaneous cytokine-secreting cells were uncommon, but there was significantly increased IFN-γ, IL-4, IL-5, and IL-10 ELISPOTs in children with CMSE and CMA compared with control subjects. IL-4 ELISPOTs were significantly greater in the blood of children with CMA compared with those with CMSE. In the lamina propria the frequencies of spontaneous cytokine-secreting cells were high compared with that in blood. Significantly increased ELISPOTs for IFN-γ and IL-4 were found in CMSE compared with controls. IL-5 ELISPOTs were unchanged, and IL-10 ELISPOTs were reduced in CMSE compared with controls. These results show a general enhancement of Th1 and Th2-type cytokine-secreting cells in the blood of children with cows milk hypersensitivity, although the increased IL-4-secreting cells in blood in CMA may be of relevance in view of the fact that this disease is IgE-mediated. In the lamina propria, there is also enhancement of IFN-γ- and IL-4-secreting cells in CMSE compared with control subjects; however, cells secreting IFN-γ are 10 times more numerous than cells secreting IL-4, showing a dominance of Th1-type responses in both controls and CMSE patients.

A consistent pattern of minor immunodeficiency and subtle enteropathy in children with multiple food allergy

OBJECTIVE Although immunoglobulin (Ig)E-mediated allergies are readily identifiable, non-IgE-mediated allergies present more diagnostic difficulty. We performed a formal retrospective analysis to determine whether there is a recognizable clinical pattern in children. METHODS We studied 121 children (mean age, 17.3 months) with multiple food allergies who were recruited on the basis of adequate immunological assessment by using case notes and parental questionnaire. RESULTS Group 1 (n=44) had rapid reactions to dietary antigens, of whom 41 also showed delayed reactions. Group 2 (n=77) had delayed reactions only. Mean IgE was increased in group 1 but both groups otherwise shared a pattern of increased IgG1, decreased IgG2/4, and low-normal IgA. Lymphocyte subsets were skewed, with an increased percentage of CD4 and CD19 and decreased CD8 and natural killer cells. Gastroesophageal reflux, esophagitis, subtle enteropathy, and constipation were frequent in both groups. Of 55 exclusively breast-fed infants, 44 sensitized before weaning. Twenty-one of the mothers suffered from autoimmunity. CONCLUSIONS There appears to be a recognizable pattern of immune deviation and minor enteropathy in children with multiple food allergy, irrespective of the speed of reactions. Disturbed gut motility is particularly common, as is a maternal history of autoimmunity.

Flat small intestinal mucosa and autoantibodies against the gut epithelium.

A male infant, aged 1 year 3 months, was admitted to the hospital with protracted diarrhoea, vomiting, and weight loss. The diarrhoea and vomiting coincided with an outbreak of acute diarrhoea and vomiting affecting other family members. Biopsy showed a flat small intestinal mucosa which did not respond to a diet free of gluten, cows milk, and eggs, or during 8 weeks of intravenous alimentation. Steroids were given, and courses of nalcrom and later cimetidine, but these did not produce any significant improvement. A rare IgG autoantibody specific for gut epithelium was found, which, when present, was associated with a cytological abnormality of crypt enteroblasts. The autoantibody disappeared after treatment with cyclophosphamide, and the cytological abnormality subsequently diminished. However, the mucosa remained severely abnormal and has been so for 23 months. It is possible that an autoimmune reaction against the patients small intestinal mucosa has led to persistence of the enteropathy.

Cryptosporidium, chronic diarrhoea and the proximal small intestinal mucosa.

The association between Cryptosporidium, chronic diarrhoea and a proximal small intestinal mucosal enteropathy was reviewed over a six and a half year period. One hundred and twenty three children with cryptosporidiosis and no clinical evidence of immune deficiency were identified. 50% of children excreting only Cryptosporidium had chronic diarrhoea. Most cases (63%) of chronic diarrhoea occurred in the first two years of life. A mild to moderate enteropathy was present in all nine children undergoing a small intestinal biopsy and seven showed the presence of Cryptosporidium adhering to villous epithelium. All patients eventually recovered spontaneously. Cryptosporidium is a cause of chronic diarrhoea and a proximal small intestinal mucosal enteropathy in children without immune deficiency. Screening for the parasite should be part of the investigative procedures in children with chronic diarrhoea.

Rectal bleeding and polyps

Colorectal polyps are an important albeit uncommon cause of rectal bleeding in children. Colonoscopy promotes both rapid and accurate diagnosis and the opportunity for immediate therapeutic polypectomy. A 10 year audit of polyps diagnosed and treated endoscopically has been undertaken in the childrens endoscopy unit. Twenty nine polyps were diagnosed from 730 colonoscopies; 24 were juvenile, two inflammatory, two Peutz-Jeghers, and one an adenomatous polyp. All but one of the juvenile polyps were solitary. All children had bleeding per rectum as one of the major presenting features. About two thirds of the patients were under the age of 5 years; the mean age was 5.6 years. Most of the juvenile polyps were on the left side of the colon; 41% were distal to the sigmoid colon. However polyps were found throughout the colon, indicating that total colonoscopy is wise and rewarding in any child with persistent and intermittent rectal bleeding.

Evaluation of infant feeding in acute gastroenteritis.

Sixty-eight bottle-fed babies under 9 months of age with mild acute gastroenteritis were observed to evaluate current feeding regimens following acute gastroenteritis in infancy. All babies were fed for 24 h with a glucose-electrolyte mixture (GEM) and then randomly assigned to either a gradual reintroduction to their normal milk, i.e., slow regrade; immediate return to full-strength formula; or a rapid regrade to a hypoallergenic whey hydrolysate formula. All groups were well matched for age, sex, ethnic origin, nutritional state, and degree of hydration. There was no significance difference in stool frequency or reducing substances, vomiting, and duration of hospital stay between the three groups. Many infants (6/24) refused to take the whey hydrolysate formula, presumably because of unpalatability. Weight gain was more rapid when full-strength milk was given. Clinical relapse developed in 12 (17%) of patients. An enteric pathogen was detected in eight of this group and cows milk protein intolerance in three (one from each feeding group). No infant had clinically significant lactose intolerance, in marked contrast to previous experience at Queen Elizabeth Hospital. In this group of previously healthy, well-nourished babies with mild acute gastroenteritis, there was no advantage in regrading slowly to milk or a hypoallergenic formula. An immediate return to normal formula 24 h after GEM feeding was well tolerated and simpler for parents.