Expression of immune checkpoint molecules on adult and neonatal T-cells.

Term and especially preterm neonates are much more susceptible to serious bacterial infections than adults. But not only the susceptibility to infection is increased in neonates, but also their risk for developing post-inflammatory diseases such as bronchopulmonary dysplasia (BPD) and periventricular leukomalacia (PVL). This may be due to an impaired ability to terminate inflammation. In the study presented here, we aimed to investigate the proliferative response and the expression of immune-checkpoint molecules (ICM) and activation markers on neonatal T-cells in comparison to adult T-cells with the hypothesis that an increased activation of neonatal T-cells may contribute to the failure of inflammation resolution observed in neonates. We show that neonatal CD4+ and CD8+ T-cells show an increased proliferative capacity and an increased expression of activation markers compared to adult T-cells upon stimulation with OKT3 as well as a decreased expression of ICM, especially PD-L1 on their surface. This decreased expression of PD-L1 by neonatal T-cells was also observed after stimulation with GBS, but not after stimulation with E. coli, the two most important pathogens in neonatal sepsis. Expression of the T-cell receptor CD3 and the co-stimulatory molecule CD28 did not differ between adult and neonatal T-cells upon bacterial stimulation. Decreased expression of ICM upon T-cell activation may be a reason for the increased risk of neonates to develop post-inflammatory diseases.

Group B streptococci infection model shows decreased regulatory capacity of cord blood cells.

BACKGROUND: Sepsis is one of the leading causes of morbidity and mortality in the neonatal period. Compared to adults, neonates are more susceptible to infections, especially to systemic infections with Group B Streptococcus (GBS). Furthermore, neonates show defects in terminating inflammation. The immunological causes for the increased susceptibility to infection and the prolonged inflammatory response are still incompletely understood. METHODS: In the present study, we aimed to investigate the reaction of cord blood mononuclear cells (MNC) to stimulation with GBS in comparison to that of MNC from adult blood with focus on the proliferative response in an in vitro infection model with heat-inactivated GBS. RESULTS: We demonstrate that after stimulation with GBS the proliferation of T cells from adult blood strongly decreased, while the proliferation of cord blood T cells remained unchanged. This effect could be traced back to a transformation of adult monocytes, but not cord blood monocytes, to a suppressive phenotype with increased expression of the co-inhibitory molecule programmed death ligand 1 (PD-L1). CONCLUSIONS: These results point towards an increased inflammatory capacity of neonatal MNC after stimulation with GBS. Targeting the prolonged inflammatory response of neonatal immune cells may be a strategy to prevent complications of neonatal infections. IMPACT: Neonatal sepsis often leads to post-inflammatory complications. Causes for sustained inflammation in neonates are incompletely understood. We show that cord blood T cells exhibited increased proliferative capacity after stimulation with group B streptococci (GBS) in comparison to adult T cells. Adult monocytes but not cord blood monocytes acquired suppressive activity and expressed increased levels of PD-L1 after GBS stimulation. Increased proliferative capacity of neonatal T cells and decreased suppressive activity of neonatal monocytes during GBS infection may contribute to prolonged inflammation and development of post-inflammatory diseases in newborns.

Cord blood granulocytic myeloid-derived suppressor cells impair monocyte T cell stimulatory capacity and response to bacterial stimulation.

BACKGROUND: Neonatal sepsis is a leading cause of perinatal morbidity and mortality. In comparison to adults, neonates exhibit a higher susceptibility to infections. Myeloid-derived suppressor cells (MDSCs) are myeloid cells with suppressive activity on other immune cells accumulating during foetal life and controlling inflammation in neonates. Most studies investigating the mechanisms for MDSC-mediated immune suppression have been focused on T-cells. Thus far, little is known about the role of MDSC for monocyte function. METHODS: The impact of human cord blood MDSCs (CB-MDSCs) on monocytes was investigated in an in vitro model. CB-MDSCs were co-cultured with peripheral blood mononuclear cells and monocytes were analysed for expression of surface markers, T cell stimulatory and phagocytic capacity, as well as the production of intracellular cytokines by flow cytometry. RESULTS: CB-MDSCs increased the expression of co-inhibitory molecules and decreased the expression of major histocompatibility complex class II molecules on monocytes, leading to an impaired T-cell stimulatory capacity. Upon bacterial stimulation, expression of phagocytosis receptors, phagocytosis rates and production of tumor necrosis factor-α by monocytes was diminished by CB-MDSCs. CONCLUSION: We show that CB-MDSCs profoundly modulate monocyte functions, thereby indirectly impairing T-cell activation. Further research is needed to figure out if MDSCs could be a therapeutic target for inflammatory diseases in neonates like neonatal sepsis.

Peroxisome proliferator-activated receptor-γ and thymic stromal lymphopoietin are involved in the pathophysiology of childhood coeliac disease.

Celiac disease (CD) is a chronic autoimmune enteropathy caused by exposure to dietary gluten in genetically predisposed individuals. The transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) was shown to exert protective effects in several immune-mediated disorders. Activation of PPARγ suppressed the expression of thymic stromal lymphopoietin (TSLP), an inducer of proinflammatory cytokines. Since the role of TSLP in gluten-sensitive enteropathy is completely unknown, we investigated the involvement of TSLP and its regulator PPARγ in childhood CD. We collected duodenal biopsy specimens from 19 children with newly diagnosed CD, 6 children with treated CD (gluten-free diet, GFD), and 10 controls. Expression of mRNA and protein levels of PPARγ, TSLP, and TSLP receptor were determined by real-time RT-PCR and Western blot, respectively. Duodenal localization of PPARγ and TSLP was studied by immunohistochemistry. In duodenal mucosa of children with CD, the amount of PPARγ was significantly lower and simultaneously that of TSLP significantly higher compared to controls (p < 0.05). In GFD-treated patients, the levels of PPARγ mRNA and protein were significantly higher while that of TSLP markedly lower compared to newly diagnosed CD (p < 0.05). Immunohistochemistry revealed PPARγ and TSLP expression in lamina propria immune cells and in enterocytes. Low expression of PPARγ and high expression of TSLP in the duodenal mucosa of children with newly diagnosed CD suggest that they are involved in the pathophysiology of CD. We hypothesize that PPARγ may be an inhibitory regulator of TSLP-stimulated inflammatory processes in CD.

Autoregressive cross-lagged models of IMPACT-III and Pediatric Crohn's Disease Activity Indexes during one year infliximab therapy in pediatric patients with Crohn's disease.

BACKGROUND: Quality of life (QoL) is an important outcome measure in the evaluation of therapies for inflammatory bowel disease. The primary aim of this study was to determine the effect of one year infliximab treatment on QoL and clinical parameters in pediatric patients with Crohn's diseases (CD). METHODS: Our prospective study involved 51 children with conventional therapy resistant, severe CD (mean age: 15.25years, range: 11-18years). Infliximab was given according to the protocol (5mg/kg, at weeks 0, 2, 6 and every 8weeks). During the infliximab courses QoL of patients was evaluated by IMPACT-III questionnaire at weeks 0, 6, 30 and 53. At the same time, the Pediatric Crohn's Disease Activity Index (PCDAI) score was calculated. Moreover, serum C-reactive protein (CRP), serum platelets and serum albumin were followed up. Auto-regressive, cross-lagged models were used to assess relation between QoL and the clinical parameters. RESULTS: The initial IMPACT-III scores [median, percentile 25-75 (pc 25-75) at week 0: 115, 102.5-130.25] increased significantly (p<0.001) following infliximab therapy at week 54 (median: 141.5, 124.5-153.75). Clinical and laboratory parameters also improved significantly (p<0.001). Auto-regressive regression coefficients (ß value) were significant between each variable over time. The strongest cross-lagged relations were observed between IMPACT-III and serum albumin, IMPACT-III and platelets. Reliability test of IMPACT-III revealed an excellent level of internal consistency (Cronbach's alpha=0.931). CONCLUSION: Infliximab treatment has beneficial clinical effect which is confirmed by decrease of PCDAI and increase of IMPACT-III. Autoregressive regression analysis showed regression relation between IMPACT-III and PCDAI and laboratory parameters.

Expression of PARK7 is increased in celiac disease.

Recently, it has been suggested that the gene called Parkinson's disease 7 (PARK7) might be an upstream activator of hypoxia-inducible factor (HIF)-1α, which plays a major role in sustaining intestinal barrier integrity. Furthermore, PARK7 has been proposed to participate in the Toll-like receptor (TLR)-dependent regulation of the innate immune system. Our aim was to investigate the involvement of PARK7 in the pathogenesis of coeliac disease (CD). Duodenal biopsy specimens were collected from 19 children with untreated CD, five children with treated CD (maintained on gluten-free diet), and ten children with histologically normal duodenal biopsies. PARK7 mRNA expression and protein level were determined by real-time polymerase chain reaction (PCR) and Western blot, respectively. Localization of PARK7 was visualized by immunofluorescence staining. Protein level of PARK7 increased in the duodenal mucosa of children with untreated CD compared to children with treated CD or to control biopsies (p <0.03). We detected intensive PARK7 staining in the epithelial cells and lamina propria of the duodenal mucosa of children with untreated CD compared with that in control biopsies. Our finding that mucosal expression of PARK7 is increased suggests that PARK7 is involved in the pathogenesis of gastrointestinal diseases, notably CD. Our results suggest that PARK7 may alter processes mediated by HIF-1α and TLR4, which supports a role for PARK7 in the maintenance of epithelial barrier integrity, immune homeostasis, or apoptosis.

Characteristics of allergic colitis in breast-fed infants in the absence of cow's milk allergy.

AIM: To investigate the characteristics of mucosal lesions and their relation to laboratory data and long-term follow up in breast-fed infants with allergic colitis. METHODS: In this study 31 breast-fed infants were prospectively evaluated (mean age, 17.4 wk) whose rectal bleeding had not ceased after a maternal elimination diet for cow's milk. Thirty-four age-matched and breast-fed infants (mean age, 16.9 wk) with no rectal bleeding were enrolled for laboratory testing as controls. Laboratory findings, colonoscopic and histological characteristics were prospectively evaluated in infants with rectal bleeding. Long-term follow-up with different nutritional regimes (L-amino-acid based formula or breastfeeding) was also included. RESULTS: Iron deficiency, peripheral eosinophilia and thrombocytosis were significantly higher in patients with allergic colitis in comparison to controls (8.4 ± 3.2 µmol/L vs 13.7 ± 4.7 µmol/L, P < 0.001; 0.67 ± 0.49 G/L vs 0.33 ± 0.17 G/L, P < 0.001; 474 ± 123 G/L vs 376 ± 89 G/L, P < 0.001, respectively). At colonoscopy, lymphonodular hyperplasia or aphthous ulceration were present in 83% of patients. Twenty-two patients were given L-amino acid-based formula and 8 continued the previous feeding. Time to cessation of rectal bleeding was shorter in the special formula feeding group (mean, 1.4 wk; range, 0.5-3 wk) when compared with the breast-feeding group (mean, 5.3 wk; range, 2-9 wk). Nevertheless, none of the patients exhibited rectal bleeding at the 3-mo visit irrespective of the type of feeding. Peripheral eosinophilia and cessation of rectal bleeding after administration of elemental formula correlated with a higher density of mucosal eosinophils. CONCLUSION: Infant hematochezia, after cow's milk allergy exclusion, is generally a benign and probably self-limiting disorder despite marked mucosal abnormality. Formula feeding results in shorter time to cessation of rectal bleeding; however, breast-feeding should not be discouraged in long-lasting hematochezia.

Low mannose-binding lectin (MBL) is associated with paediatric inflammatory bowel diseases and ileal involvement in patients with Crohn disease.

BACKGROUND: Mannose-binding lectin (MBL) is a pattern-recognition molecule of the innate immune system and may be involved in the pathogenesis of inflammatory bowel disease (IBD). Our aim was to assess the prevalence of MBL deficiency in a cohort of patients with paediatric-onset IBD and study whether it is associated with the clinical manifestations, serum antibody formation, or genetic factors. METHODS: This prospective study included 159 paediatric patients (mean age: 14.0 years) with IBD [107 patients with Crohn disease (CD) and 52 patients with ulcerative colitis (UC)]. Furthermore, 95 controls were investigated. Serum samples were determined for MBL by enzyme-linked immunosorbent assay (ELISA) and for serologic markers [autoantibodies against Saccharomyces cerevisiae (ASCA) and perinuclear components of neutrophils (pANCA)] by indirect immunofluorescent assay. NOD2/CARD15 variants were tested by polymerase chain reaction/restriction fragment length polymorphism. RESULTS: The MBL serum concentration was significantly lower in IBD patients(both with CD and UC) compared to controls (IBD, p=0.007, CD, p=0.04, UC p=0.004). Prevalence of low MBL level (<500 ng/mL) was significantly higher in both CD and UC groups compared to controls (p=0.002 and p=0.006). Furthermore, low MBL level was associated with isolated ileal involvement (p=0.01) and MBL deficiency (<100 ng/mL) with male gender (p=0.004) in patients with CD. We failed to confirm any correlation between MBL deficiency and serum autoantibodies or NOD2/CARD15 variants. CONCLUSIONS: Our results suggest that low MBL associated with paediatric-onset IBD and ileal CD may be considered an additional marker of the IBD pathogenesis.

[The role of intestinal alkaline phosphatase in pediatric inflammatory bowel and celiac diseases]. / Az intestinalis alkalikus foszfatáz szerepe gyermekkori gyulladásos bélbetegségben és coeliakiában.

Intestinal alkaline phosphatase enzyme plays a pivotal role in the maintenance of intestinal mucosal barrier integrity with the detoxification capacity of lipopolysaccharide, the ligand of Toll-like receptor 4. The inappropriate immune responses and the damage of the mucosal barrier may contribute to the initiation of inflammatory bowel and celiac diseases. In the inflamed colonic mucosa of children with inflammatory bowel disease and in the duodenal mucosa of newly diagnosed children with celiac disease, the decreased intestinal alkaline phosphatase and increased Toll-like receptor 4 protein expression may generate enhanced lipopolysaccharide activity, which may strengthen tissue damaging processes. The enhancement of intestinal alkaline phosphatase activity in an animal model of colitis and in therapy resistant, adult patients with ulcerative colitis reduced the symptoms of intestinal inflammation. In accordance with these results, the targeted intestinal administration of the enzyme in the two examined disorders may be a supplemental therapeutic option in the future.

Intestinal alkaline phosphatase in the colonic mucosa of children with inflammatory bowel disease.

AIM: To investigate intestinal alkaline phosphatase (iAP) in the intestinal mucosa of children with inflammatory bowel disease (IBD). METHODS: Colonic biopsy samples were taken from 15 newly diagnosed IBD patients and from 10 healthy controls. In IBD patients, specimens were obtained both from inflamed and non-inflamed areas. The iAP mRNA and protein expression was determined by reverse transcription-polymerase chain reaction and Western blotting analysis, respectively. Tissue localization of iAP and Toll-like receptor (TLR) 4 was investigated by immunofluorescent staining. RESULTS: The iAP protein level in the inflamed mucosa of children with Crohn's disease (CD) and ulcerative colitis (UC) was significantly decreased when compared with controls (both P < 0.05). Similarly, we found a significantly decreased level of iAP protein in the inflamed mucosa in CD compared with non-inflamed mucosa in CD (P < 0.05). In addition, the iAP protein level in inflamed colonic mucosa in patients with UC was decreased compared with non-inflamed mucosa in patients with CD (P < 0.05). iAP protein levels in the non-inflamed mucosa of patients with CD were similar to controls. iAP mRNA expression in inflamed colonic mucosa of children with CD and UC was not significantly different from that in non-inflamed colonic mucosa with CD. Expression of iAP mRNA in patients with non-inflamed mucosa and in controls were similar. Co-localization of iAP with TLR4 showed intense staining with a dotted-like pattern. iAP was present in the inflamed and non-inflamed mucosa of patients with CD, UC, and in control biopsy specimens, irrespective of whether it was present in the terminal ileum or in the colon. However, the fluorescent signal of TLR4 was more pronounced in the colon compared with the terminal ileum in all groups studied. CONCLUSION: Lower than normal iAP protein levels in inflamed mucosa of IBD patients may indicate a role for iAP in inflammatory lesions in IBD. Based on our results, administration of exogenous iAP enzyme to patients with the active form of IBD may be a therapeutic option.

Pancreatic autoantibodies and autoantibodies against goblet cells in pediatric patients with inflammatory bowel disease.

BACKGROUND: Significance of pancreatic autoantibodies determined by using exocrine pancreas (PAB) and antibodies against recombinant pancreas antigen (rPAB), as well as the importance of autoantibodies against goblet cells (GAB), is not known in pediatric patients with inflammatory bowel disease (IBD). Our aim was to determine the complex analysis of PAB, rPAB, GAB, antibodies against Saccharomyces cerevisiae, and perinuclear components of neutrophils in pediatric patients with IBD. Moreover, association with NOD2/CARD15 and disease phenotype was determined. METHODS: A total of 152 pediatric patients (median age 13.9 years) with IBD (103 patients with Crohn disease [CD] and 49 patients with ulcerative colitis [UC]) and 104 controls were included. Serum autoantibodies were determined by indirect immunofluorescence assay. NOD2/CARD15 variants were tested by polymerase chain reaction/restriction fragment length polymorphism. RESULTS: The presence of PAB and rPAB was significantly higher in CD (34% and 35.9%) and in UC (20.4% and 24.5%) compared with pediatric control cohort (0% and 0%, P<0.0001). In addition, GAB positivity was significantly increased in patients with UC in comparison with CD and controls, respectively (UC, 12.2%; CD, 1.9%; controls, 1.9%; P=0.02). Specificity of PAB and rPAB was 100%; however, sensitivity was low. The combination of PAB and/or antibodies against Saccharomyces cerevisiae/perinuclear components of neutrophils improved the sensitivity of serological markers in CD (87.4%) and in UC (79.6%); specificities were 89.3% and 93.2%, respectively. Pancreatic autoantibodies (PAB, rPAB) and GAB were not related to clinical presentation, medical therapy, or need for surgery in CD or in UC. CONCLUSIONS: Pancreatic autoantibodies and GAB were specific for IBD, but the sensitivity was limited as well because there was lack of correlation with clinical phenotype. Combinations of these antibodies have shown increased sensitivity; therefore, it may be recommended in the diagnostic procedure of IBD.

Diagnostic yield of upper endoscopy in paediatric patients with Crohn's disease and ulcerative colitis. Subanalysis of the HUPIR registry.

BACKGROUND, AIMS: According to Porto Criteria upper gastrointestinal (UGI) endoscopy is recommended in patients with suspected inflammatory bowel disease (IBD). Nevertheless, previous studies revealed frequent involvement of UGI tract even in patients with ulcerative colitis (UC). The aim of the present study was to determine the diagnostic role of esophagogastroduodenoscopy (EGD) and assess the prevalence and different aspects of UGI involvement in children registered in the Hungarian Pediatric IBD Registry (HUPIR) from 1st of January 2007 to 31th of December 2009. METHODS: Twenty seven institutes provided prospective follow-up data about newly diagnosed IBD patients to HUPIR. The registry was based on detailed questionnaire (76 parameters) involving anamnestic data, laboratory findings, activity indexes, diagnostic procedures, endoscopic examinations (EGD and ileocolonoscopy), and histological data. Localization and phenotype of disease were based on the Montreal classification criteria. RESULTS: During the 3-year period 420 children were diagnosed with IBD, 265 (63%) of them had Crohn's disease (CD), 130 (31%) UC, and 25 (6%) IBD-unclassified (IBD-U). The mean age at diagnosis was 13.2 years (range: 1.2-18 years). EGD was performed in 237 patients (56%), in most cases in patients suffering from CD. Macroscopic lesions on EGD were noted in 64% of patients with CD and 40% of children with UC. Characteristic lesions for CD (ulcer, erosion, aphthous lesion, and granuloma) were noted in 31% of CD patients, however, EGD helped to establish the final diagnosis in 9% of CD patients (diagnostic yield, 9%). CONCLUSIONS: There was a high frequency of UGI involvement in children with CD and UC. One third of CD patients showed significant lesions at upper endoscopy and one patient out of ten had real diagnostic help from EGD.

Decreased mucosal expression of intestinal alkaline phosphatase in children with coeliac disease.

A major function of the enzyme intestinal alkaline phosphatase (iAP) is the detoxification of lipopolysaccharide (LPS), the ligand of Toll-like receptor 4 (TLR4). Hence, iAP has a role in the defence of maintaining intestinal barrier integrity. As intestinal barrier integrity is impaired in coeliac disease (CD), we tested the expression and localization of iAP in duodenal mucosa specimens from children with newly diagnosed CD (n = 10), with CD on gluten-free diet (GFD) (n = 5) and compared to those from ten healthy children. The mRNA and protein expression was determined by RT-PCR and Western blot analysis, respectively. Tissue localization of iAP and TLR4 was determined by immunofluorescence staining. iAP protein expression level was significantly lower than normal in newly diagnosed CD, while it was normalised in children on GFD. iAP and TLR4 colocalized at the epithelial surface of duodenal mucosa in each group of subjects enrolled. The finding of decreased iAP protein levels in newly diagnosed CD is consistent with its role in decreased intestinal barrier integrity. The latter may be the result of decreased LPS-detoxifying ability.

Immune phenotype of children with newly diagnosed and gluten-free diet-treated celiac disease.

BACKGROUND: Recent data suggest the involvement of both the adaptive and the innate immune system in celiac disease (CD). However, little is known about the immune phenotype of children with CD and its alteration upon dietary intervention. AIMS: We characterized the prevalence of major interacting members of the adaptive and innate immune system in peripheral blood of newly diagnosed children with CD and tested its alteration with the improvement of clinical signs after the introduction of gluten-free diet (GFD). METHODS: Peripheral blood was taken from ten children with biopsy-proven CD at the time of diagnosis and after the resolution of clinical symptoms following GFD. As controls, 15 children with functional abdominal pain were enrolled. The prevalence of the cells of adaptive and innate immunity was measured with labeled antibodies against surface markers and intracellular FoxP3 using a flow cytometer. RESULTS: Patients with CD were found to have lower T helper, Th1 and natural killer (NK), NKT and invariant NKT cell prevalence and with higher prevalence of activated CD4(+) cells, myeloid dendritic cells (DC) and Toll-like receptor (TLR) 2 and TLR-4 positive DCs and monocytes compared to controls. After resolution of symptoms on GFD, the majority of these changes normalized, although the prevalence of NK and NKT cell, DC and TLR-2 expressing DCs and monocytes remained abnormal. CONCLUSIONS: The immune phenotype in childhood CD indicates the implication of both adaptive and innate immune system. The normalization of immune abnormalities occurs on GFD, but the kinetics of this process probably differs among different cell types.

Immune phenotype in children with therapy-naïve remitted and relapsed Crohn's disease.

AIM: To characterize the prevalence of subpopulations of CD4+ cells along with that of major inhibitor or stimulator cell types in therapy-naïve childhood Crohn's disease (CD) and to test whether abnormalities of immune phenotype are normalized with the improvement of clinical signs and symptoms of disease. METHODS: We enrolled 26 pediatric patients with CD. 14 therapy-naïve CD children; of those, 10 children remitted on conventional therapy and formed the remission group. We also tested another group of 12 children who relapsed with conventional therapy and were given infliximab; and 15 healthy children who served as controls. The prevalence of Th1 and Th2, naïve and memory, activated and regulatory T cells, along with the members of innate immunity such as natural killer (NK), NK-T, myeloid and plasmocytoid dendritic cells (DCs), monocytes and Toll-like receptor (TLR)-2 and TLR-4 expression were determined in peripheral blood samples. RESULTS: Children with therapy-naïve CD and those in relapse showed a decrease in Th1 cell prevalence. Simultaneously, an increased prevalence of memory and activated lymphocytes along with that of DCs and monocytes was observed. In addition, the ratio of myeloid /plasmocytoid DCs and the prevalence of TLR-2 or TLR-4 positive DCs and monocytes were also higher in therapy-naïve CD than in controls. The majority of alterations diminished in remitted CD irrespective of whether remission was obtained by conventional or biological therapy. CONCLUSION: The finding that immune phenotype is normalized in remission suggests a link between immune phenotype and disease activity in childhood CD. Our observations support the involvement of members of the adaptive and innate immune systems in childhood CD.

Regulatory T cells and T helper subsets in breast-fed infants with hematochezia caused by allergic colitis.

The objective of our study was to investigate the prevalence of CD4 T lymphocyte subsets and their commitment to TH1 or TH2 direction in 10 infants with allergic colitis (AC) and 10 healthy controls. Infants with AC presented with a higher ratio of naïve to memory cells, lower prevalence of activated CD4CD25 cells and FoxP3 regulatory cells, and a shift to TH2 direction in balance compared with controls. These alterations are normalized upon cessation of AC symptoms on elemental L-amino acid formula. These findings suggest the importance of antigen exposure in AC in infancy.

Increased expression of hypoxia-inducible factor 1alpha in coeliac disease.

Previously, it has been suggested that hypoxia-inducible factor (HIF) 1 signaling may play determinative role in the maintenance of the barrier function of the intestinal epithelium in inflammatory bowel disease. Our aim was to depict the alteration of HIF-1alpha and related genes in celiac disease (CD) where the importance of the barrier function is well known. Duodenal biopsy specimens were collected from 16 children with untreated CD, 9 children with treated CD and 10 controls. HIF-1alpha, trefoil factor 1 (TFF1), ecto-5-prime nucleotidase (CD73), and multi drug resistance gene 1 (MDR1) mRNA and HIF-1alpha protein expression were determined by real-time PCR and Western blot, respectively. Localization of HIF-1alpha was determined by immunofluorescent staining. We found increased HIF-1alpha and TFF1 mRNA and HIF-1alpha protein expression in the duodenal mucosa of children with untreated CD compared with controls or children with treated CD (p < 0.05). In untreated CD children, HIF-1alpha staining was present in cytoplasmic and nuclear region of the villous enterocytes. In treated CD mRNA expression of CD73 and MDR1 were increased compared with controls (p < 0.01 and 0.05, respectively). Our results of increased mucosal HIF-1alpha expression in CD children suggest the contribution of this signaling pathway in the pathomechanism of CD.

Mucosal expression of claudins 2, 3 and 4 in proximal and distal part of duodenum in children with coeliac disease.

Duodenal biopsy is an important tool to diagnose coeliac disease (CD); however, the most reliable location of biopsy site is still questionable. Claudins (CLDNs), members of a large family of adherent junction proteins, show characteristic expression pattern in inflammatory disorders; nevertheless, CLDN expression in CD is unknown. This is a comparative study to examine the CLDN 2, 3 and 4 expressions in proximal and distal part of duodenum in children with CD and in controls. Thirty-three children with newly diagnosed CD were enrolled. Fourteen healthy children served as controls. Biopsies from proximal and distal part of duodenum were taken for routine histological analysis. Immunohistochemistry were used to detect CD3+ intraepithelial lymphocytes and CLDN 2, 3 and 4 protein expressions. Macroscopic picture, routine histology and Marsh grade depicted no differences between biopsies taken from proximal or distal part of duodenum. However, CLDN 2 expression was significantly increased in severe form of coeliac disease in bulb and in distal duodenum, and in distal part of non-severe coeliac patients, in comparison to controls. Similar association was found concerning CLDN 3 expression. Expression of CLDN 4 was similar in all groups studied. Both proximal and distal mucosal duodenal biopsies are suitable for diagnosing villous atrophy in patients with CD. Increased expressions of CLDN 2 and 3 suggest structural changes of tight junction in coeliac disease which may be, at least in part, responsible for increased permeability and proliferation observed in coeliac disease.

[Adalimumab treatment in infliximab-resistant pediatric patient with Crohn's disease]. / Infliximab-rezisztens Crohn-beteg gyermek adalimumab-kezelése.

Treatment with the chimeric monoclonal antibody (infliximab) is highly effective in refractory and fistulising Crohn's disease, nevertheless, infliximab resistance may occur. Authors report a 12-year-old boy with infliximab refractory luminal Crohn's disease including 3 active perianal fistulas. The patient was treated successfully with adalimumab, a fully human anti-tumor necrosis factor alpha monoclonal antibody. After 10 weeks of therapy, the previously high activity index returned to normal and the fistulas were closed. Quality of life using validated questionnaire improved significantly also. Adalimumab might be a suitable therapy even in pediatric Crohn's disease patients with infliximab resistance.