Franco Torrente

Small intestinal enteropathy with epithelial IgG and complement deposition in children with regressive autism.

We have reported lymphocytic colitis in children with regressive autism, with epithelial damage prominent. We now compare duodenal biopsies in 25 children with regressive autism to 11 with coeliac disease, five with cerebral palsy and mental retardation and 18 histologically normal controls. Immunohistochemistry was performed for lymphocyte and epithelial lineage and functional markers. We determined the density of intraepithelial and lamina propria lymphocyte populations, and studied mucosal immunoglobulin and complement C1q localisation. Standard histopathology showed increased enterocyte and Paneth cell numbers in the autistic children. Immunohistochemistry demonstrated increased lymphocyte infiltration in both epithelium and lamina propria with upregulated crypt cell proliferation, compared to normal and cerebral palsy controls. Intraepithelial lymphocytes and lamina propria plasma cells were lower than in coeliac disease, but lamina propria T cell populations were higher and crypt proliferation similar. Most strikingly, IgG deposition was seen on the basolateral epithelial surface in 23/25 autistic children, co-localising with complement C1q. This was not seen in the other conditions. These findings demonstrate a novel form of enteropathy in autistic children, in which increases in mucosal lymphocyte density and crypt cell proliferation occur with epithelial IgG deposition. The features are suggestive of an autoimmune lesion.

Intestinal Lymphocyte Populations in Children with Regressive Autism: Evidence for Extensive Mucosal Immunopathology

Inflammatory intestinal pathology has been reported in children with regressive autism (affected children). Detailed analysis of intestinal biopsies in these children indicates a novel lymphocytic enterocolitis with autoimmune features; however, links with cognitive function remain unclear. To characterize further, the nature and extent of this disease we examined the mucosal infiltrate using flow cytometry. Duodenal, ileal, and colonic biopsies were obtained from 52 affected children, 25 histologically normal, and 54 histologically inflamed, developmentally normal controls. Epithelial and lamina propria lymphocyte populations were isolated and examined by multicolor flow cytometry. Adjacent biopsies were assessed by semiquantitative histopathology. At all sites, CD3+ and CD3+CD8+ IEL as well as CD3+ LPL were significantly increased in affected children compared with developmentally normal noninflamed control groups (p<0.01) reaching levels similar to inflamed controls. In addition, two populations—CD3+CD4+ IEL and LP CD19+ B cells—were significantly increased in affected children compared with both noninflamed and inflamed control groups including IBD, at all sites examined (p<0.01). Histologically there was a prominent mucosal eosinophil infiltrate in affected children that was significantly lower in those on a gluten- and casein-free diet, although lymphocyte populations were not influenced by diet.The data provide further evidence of a pan-enteric mucosal immunopathology in children with regressive autism that is apparently distinct from other inflammatory bowel diseases.

Spontaneous Mucosal Lymphocyte Cytokine Profiles in Children with Autism and Gastrointestinal Symptoms: Mucosal Immune Activation and Reduced Counter Regulatory Interleukin-10

A lymphocytic enterocolitis has been reported in a cohort of children with autistic spectrum disorder (ASD) and gastrointestinal (GI) symptoms. This study tested the hypothesis that dysregulated intestinal mucosal immunity with enhanced pro-inflammatory cytokine production is present in these ASD children. Comparison was made with developmentally normal children with, and without, mucosal inflammation. Duodenal and colonic biopsies were obtained from 21 ASD children, and 65 developmentally normal paediatric controls, of which 38 had signs of histological inflammation. Detection of CD3+ lymphocyte staining for spontaneous intracellular TNFα, IL-2, IL-4, IFNγ, and IL-10, was performed by multicolor flow cytometry. Duodenal and colonic mucosal CD3+ lymphocyte counts were elevated in ASD children compared with noninflamed controls (p<0.03). In the duodenum, the proportion of lamina propria (LP) and epithelial CD3+TNFα+ cells in ASD children was significantly greater compared with noninflamed controls (p<0.002) but not coeliac disease controls. In addition, LP and epithelial CD3+IL-2+ and CD3+IFNγ+, and epithelial CD3+IL-4+ cells were more numerous in ASD children than in noninflamed controls (p<0.04). In contrast, CD3+IL-10+ cells were fewer in ASD children than in noninflamed controls (p<0.05). In the colon, LP CD3+TNFα+ and CD3+IFNγ+ were more frequent in ASD children than in noninflamed controls (p<0.01). In contrast with Crohn’s disease and non-Crohn’s colitis, LP and epithelial CD3+IL-10+ cells were fewer in ASD children than in nondisease controls (p<0.01). There was a significantly greater proportion of CD3+TNFα+ cells in colonic mucosa in those ASD children who had no dietary exclusion compared with those on a gluten and/or casein free diet (p<0.05). There is a consistent profile of CD3+ lymphocyte cytokines in the small and large intestinal mucosa of these ASD children, involving increased pro-inflammatory and decreased regulatory activities. The data provide further evidence of a diffuse mucosal immunopathology in some ASD children and the potential for benefit of dietary and immunomodulatory therapies.

Focal-Enhanced Gastritis in Regressive Autism with Features Distinct from Crohn's and Helicobacter Pylori Gastritis

BACKGROUND:Immunohistochemistry allowed recent recognition of a distinct focal gastritis in Crohns disease. Following reports of lymphocytic colitis and small bowel enteropathy in children with regressive autism, we aimed to see whether similar changes were seen in the stomach. We thus studied gastric antral biopsies in 25 affected children, in comparison to 10 with Crohns disease, 10 with Helicobacter pylori infection, and 10 histologically normal controls. All autistic, Crohns, and normal patients were H. pylori negative.METHODS:Snap-frozen antral biopsies were stained for CD3, CD4, CD8, γδ T cells, HLA-DR, IgG, heparan sulphate proteoglycan, IgM, IgA, and C1q. Cell proliferation was assessed with Ki67.RESULTS:Distinct patterns of gastritis were seen in the disease states: diffuse, predominantly CD4+ infiltration in H. pylori, and focal-enhanced gastritis in Crohns disease and autism, the latter distinguished by striking dominance of CD8+ cells, together with increased intraepithelial lymphocytes in surface, foveolar and glandular epithelium. Proliferation of foveolar epithelium was similarly increased in autism, Crohns disease and H. pylori compared to controls. A striking finding, seen only in 20/25 autistic children, was colocalized deposition of IgG and C1q on the subepithelial basement membrane and the surface epithelium.CONCLUSIONS:These findings demonstrate a focal CD8-dominated gastritis in autistic children, with novel features. The lesion is distinct from the recently recognized focal gastritis of Crohns disease, which is not CD8-dominated. As in the small intestine, there is epithelial deposition of IgG.

A British Society of Paediatric Gastroenterology, Hepatology and Nutrition survey of the effectiveness and safety of adalimumab in children with inflammatory bowel disease

Aliment Pharmacol Ther 2011; 33: 946–953

Enteropathogenic Escherichia coli O125:H6 Triggers Attaching and Effacing Lesions on Human Intestinal Biopsy Specimens Independently of Nck and TccP/TccP2

ABSTRACT Typical enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) employ either Nck, TccP/TccP2, or Nck and TccP/TccP2 pathways to activate the neuronal Wiskott-Aldrich syndrome protein (N-WASP) and to trigger actin polymerization in cultured cells. This phenotype is used as a marker for the pathogenic potential of EPEC and EHEC strains. In this paper we report that EPEC O125:H6, which represents a large category of strains, lacks the ability to utilize either Nck or TccP/TccP2 and hence triggers actin polymerization in vitro only inefficiently. However, we show that infection of human intestinal biopsies with EPEC O125:H6 results in formation of typical attaching and effacing lesions. Expression of TccP in EPEC O125:H6, which harbors an EHEC O157-like Tir, resulted in efficient actin polymerization in vitro and enhanced colonization of human intestinal in vitro organ cultures with detectable N-WASP and electron-dense material at the site of bacterial adhesion. These results show the existence of a natural category of EPEC that colonizes the gut mucosa using Nck- and TccP-independent mechanisms. Importantly, the results highlight yet again the fact that conclusions made on the basis of in vitro cell culture models cannot be extrapolated wholesale to infection of mucosal surfaces and that the ability to induce actin polymerization on cultured cells should not be used as a definitive marker for EPEC and EHEC virulence.

Expression of Human Beta-Defensins in Children with Chronic Inflammatory Bowel Disease

Background Human beta-defensins (hBDs) are antimicrobial peptides known to play a major role in intestinal innate host defence. Altered mucosal expression of hBDs has been suggested to be implicated in chronic inflammatory bowel disease pathogenesis. However, little is known about expression of these peptides in children. Methods Intestinal biopsies were obtained from the duodenum (n = 88), terminal ileum (n = 90) and ascending colon (n = 105) of children with Crohns disease (n = 26), ulcerative colitis (n = 11) and healthy controls (n = 16). Quantitative real-time (RT) PCR was performed and absolute mRNA copy numbers analyzed for hBD1-3 as well as inflammatory cytokines IL-8 and TNF-alpha. Results Significant induction of hBD2 and hBD3 was observed in the inflamed terminal ileum and ascending colon of IBD children. In the ascending colon induction of hBD2 was found to be significantly lower in children with Crohns disease compared to ulcerative colitis. A strong correlation was found between inducible defensins hBD2 and 3 and the inflammatory cytokines IL-8 and TNF-alpha, both in the terminal ileum and ascending colon. Conclusion Our study demonstrates distinct changes in hBD expression throughout the intestinal tract of children with IBD, lending further support for their potential role in disease pathogenesis.

Reduced production of sulfated glycosaminoglycans occurs in Zambian children with kwashiorkor but not marasmus

BACKGROUND Kwashiorkor, a form of severe malnutrition with high mortality, is characterized by edema and systemic abnormalities. Although extremely common, its pathophysiology remains poorly understood, and its characteristic physical signs are unexplained. OBJECTIVE Because kwashiorkor can develop in protein-losing enteropathy, which is caused by a loss of enterocyte heparan sulfate proteoglycan (HSPG), and previous observations suggest abnormal sulfated glycosaminoglycan (GAG) metabolism, we examined whether intestinal GAG and HSPG are abnormal in children with kwashiorkor. DESIGN Duodenal biopsy samples collected from Zambian children with marasmus (n = 18), marasmic kwashiorkor (n = 8), and kwashiorkor (n = 15) were examined for expression of HSPG, GAGs, and immunologic markers and compared against reference samples from healthy UK control children. GAG and HSPG expression density and inflammatory cell populations were quantitated by computerized analysis. RESULTS The kwashiorkor group was less wasted and had a lower HIV incidence than did the other groups. All duodenal biopsy samples showed inflammation compared with the histologically uninflamed control samples. Biopsy samples from marasmic children had greater inflammation and greater CD3+ and HLA-DR (human leukocyte antigen DR)-positive cell densities than did samples from children with kwashiorkor. Expression of both HSPG and GAGs was similar between marasmic and well-nourished UK children but was markedly lower in children with kwashiorkor in both the epithelium and lamina propria. Although underglycosylated and undersulfated, epithelial syndecan-1 protein was normally expressed in kwashiorkor, which confirmed that abnormalities arise after core protein synthesis. CONCLUSIONS Intestinal HSPG loss occurs in kwashiorkor, which may precipitate protein-losing enteropathy to cause edema. If occurring systemically, impaired HSPG expression could cause several previously unexplained features of kwashiorkor. We speculate that a genetic predisposition to reduced HSPG biosynthesis may offer a contrasting selective advantage, by both diminishing protein catabolism during transient undernutrition and protecting against specific infectious diseases.

Defining eosinophilic colitis in children: insights from a retrospective case series.

Objectives: Although it is a well-described syndrome in infants, eosinophilic colitis is a loosely defined and poorly understood diagnosis in older children. The aims of this case series were to characterise colonic eosinophilia in children and to determine whether it represents a distinct clinicopathological condition. Methods: We retrospectively reviewed symptomatic children older than 12 months with the principal diagnosis of colonic eosinophilia who presented between January 2000 and February 2007 (n = 38) and a further 10 children whose colonic biopsies were reported as histologically normal. The eosinophil density in all available gastrointestinal biopsies (n = 620) of these children was determined using a validated quantitative morphometric method. Patients were subdivided according to mean colonic eosinophil levels into 3 groups (marked, moderate, or minimal colonic eosinophilia). The following patient information was obtained and compared among patient groups: symptoms prompting endoscopy, atopic history, outcome, serum C-reactive protein and total immunoglobulin E (IgE) levels, erythrocyte sedimentation rate, blood eosinophil count, and endoscopic findings. Results: In all 3 patient groups, there was a colonic gradient of decreasing eosinophil density from caecum to rectum. Upper gastrointestinal tract biopsies did not exhibit eosinophilia. Although a significant association (P = 0.03) between abnormal total IgE levels and moderate or severe colonic eosinophilia was found, there was no significant difference (P > 0.05) in other patient characteristics. Furthermore, follow-up data did not show a consistent relation between eosinophil density and progression of symptoms. Conclusions: We find no association between “eosinophilic colitis,” defined as a histologically demonstrated marked colonic eosinophilia, and symptoms, history of atopy, inflammatory markers, or clinical outcome.

Intestinal alpha‐defensin expression in pediatric inflammatory bowel disease

Background: Reduced alpha‐defensin expression has been reported in the terminal ileum (TI) of adult patients with ileal Crohns disease (CD). However, little is known about alpha‐defensin expression in children with chronic inflammatory bowel disease (IBD). Methods: In all, 283 intestinal biopsies were obtained from children with CD, ulcerative colitis (UC), and healthy controls. Absolute mRNA copy numbers for HD5, HD6, IL‐8, Villin 1, and Tcf‐4 were analyzed by reverse‐transcription polymerase chain reaction (RT‐PCR). HD5 immunostaining was performed on biopsy sections and patients genotyped for NOD2 mutations. Results: Equal expression levels of alpha‐defensins (HD5 and HD6) were found in TI biopsies of children with ileal CD (L1+L3) compared to patients with colonic disease (L2) and healthy controls. In contrast, we found significantly higher levels of alpha‐defensins in the TI of children with UC compared to CD and controls. Reduced expression of Tcf‐4 was observed exclusively in the duodenum and TI of CD patients with L1+L3 phenotype. We demonstrate significantly increased expression of HD5 and HD6 in the inflamed colon of IBD children (UC and CD) attributable to the presence of metaplastic Paneth cells. Conclusions: In this study no difference in alpha‐defensin expression was found in the TI of CD children and controls. However, significant reduction of Tcf‐4 in L1+L3 phenotype suggests that a possibly impaired PC differentiation may lead to altered HD5 and HD6 expression at some stage of disease. Additionally, substantially increased expression of alpha‐defensins in the inflamed colonic mucosa of children with IBD raises the question for their potential involvement in modulating inflammation in these patients. (Inflamm Bowel Dis 2010;)