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

l-Isoleucine Administration Alleviates DSS-Induced Colitis by Regulating TLR4/MyD88/NF-κB Pathway in Rats

Inflammatory bowel disease (namely, colitis) severely impairs human health. Isoleucine is reported to regulate immune function (such as the production of immunoreactive substances). The aim of this study was to investigate whether l-isoleucine administration might alleviate dextran sulfate sodium (DSS)-induced colitis in rats. In the in vitro trial, IEC-18 cells were treated by 4 mmol/L l-isoleucine for 12 h, which relieved the decrease of cell viability that was induced by TNF-α (10 ng/ml) challenge for 24 h (P <0.05). Then, in the in vivo experiment, a total of 44 Wistar rats were allotted into 2 groups that were fed l-isoleucine-supplemented diet and control diet for 35 d. From 15 to 35 d, half of the rats in the 2 groups drank the 4% DSS-adding water. Average daily gain, average daily feed intake and feed conversion of rats were impaired by DSS challenge (P <0.05). Drinking the DSS-supplementing water also increased disease activity index (DAI) and serum urea nitrogen level (P <0.05), shortened colonic length (P <0.05), impaired colonic enterocyte apoptosis, cell cycle, and the ZO-1 mRNA expression (P <0.05), increased the ratio of CD11c-, CD64-, and CD169-positive cells in colon (P <0.05), and induced extensive ulcer, infiltration of inflammatory cells, and collagenous fiber hyperplasia in colon. However, dietary l-isoleucine supplementation attenuated the negative effect of DSS challenge on growth performance (P <0.05), DAI (P <0.05), colonic length and enterocyte apoptosis (P <0.05), and dysfunction of colonic histology, and downregulated the ratio of CD11c-, CD64-, and CD169-positive cells, pro-inflammation cytokines and the mRNA expression of TLR4, MyD88, and NF-κB in the colon of rats (P <0.05). These results suggest that supplementing l-isoleucine in diet improved the DSS-induced growth stunting and colonic damage in rats, which could be associated with the downregulation of inflammation via regulating TLR4/MyD88/NF-κB pathway in colon.

Non-IgE-Mediated Gastrointestinal Food Protein-Induced Allergic Disorders. Clinical Perspectives and Analytical Approaches

Non-IgE-mediated gastrointestinal food allergy (non-IgE-GI-FA) is the name given to a series of pathologies whose main entities are food protein-induced allergic proctocolitis (FPIAP), food protein-induced enteropathy (FPE), and food protein-induced enterocolitis syndrome (FPIES). These are more uncommon than IgE-mediated food allergies, their mechanisms remain largely unknown, and their diagnosis is mainly done by clinical history, due to the lack of specific biomarkers. In this review, we present the latest advances found in the literature about clinical aspects, the current diagnosis, and treatment options of non-IgE-GI-FAs. We discuss the use of animal models, the analysis of gut microbiota, omics techniques, and fecal proteins with a focus on understanding the pathophysiological mechanisms of these pathologies and obtaining possible diagnostic and/or prognostic biomarkers. Finally, we discuss the unmet needs that researchers should tackle to advance in the knowledge of these barely explored pathologies.

Specific MicroRNA Pattern in Colon Tissue of Young Children with Eosinophilic Colitis

Eosinophilic colitis (EC) is a common cause of haematochezia in infants and young children. The exact pathomechanism is not understood, and the diagnosis is challenging. The role of microRNAs as key class of regulators of mRNA expression and translation in patients with EC has not been explored. Therefore, the aim of the present study was to explore the miRNA profile in EC with respect to eosinophilic inflammation. Patients enrolled in the study (n = 10) had persistent rectal bleeding, and did not respond to elimination dietary treatment. High-throughput microRNA sequencing was carried out on colonic biopsy specimens of children with EC (EC: n = 4) and controls (C: n = 4) as a preliminary screening of the miRNA profile. Based on the next-generation sequencing (NGS) results and literature data, a potentially relevant panel of miRNAs were selected for further measurements by real-time reverse transcription (RT)-PCR (EC: n = 14, C: n = 10). Validation by RT-PCR resulted in significantly altered expression of miR-21, -31, -99b, -125a, -146a, -184, -221, -223, and -559 compared to controls (p ≤ 0.05). Elevation in miR-21, -99b, -146a, -221, and -223 showed statistically significant correlation to the extent of tissue eosinophilia. Based on our results, we conclude that the dysregulated miRNAs have a potential role in the regulation of apoptosis by targeting Protein kinase B/Mechanistic target of rapamycin (AKT/mTOR)-related pathways in inflammation by modulating Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-related signalling and eosinophil cell recruitment and activation, mainly by regulating the expression of the chemoattractant eotaxin and the adhesion molecule CD44. Our results could serve as a basis for further extended research exploring the pathomechanism of EC.

Food Protein-Induced Enterocolitis Syndrome, Allergic Proctocolitis, and Enteropathy

Food protein-induced enterocolitis (FPIES), allergic proctocolitis (FPIAP), and enteropathy (FPE) are among a number of immune-mediated reactions to food that are thought to occur primarily via non-IgE-mediated pathways. All three are typically present in infancy and are triggered most commonly by cow's milk protein. The usual presenting features are vomiting with lethargy and dehydration in FPIES; bloody and mucous stools in FPIAP; and diarrhea with malabsorption and failure to thrive in FPE. Diagnosis is based on convincing history and resolution of symptoms with food avoidance; confirmatory diagnostic testing other than food challenge is lacking. The mainstay of management is avoidance of the suspected inciting food, with interval challenge to assess for resolution, which usually occurs in the first years of life. Studies published in the past few years clarify common presenting features, report additional culprit foods, address potential biomarkers, and suggest new management strategies.

Intraepithelial lymphocyte eotaxin-2 expression and perineural mast cell degranulation differentiate allergic/eosinophilic colitis from classic IBD

OBJECTIVES

Allergic colitis shows overlap with classic inflammatory bowel disease (IBD). Clinically, allergic colitis is associated with dysmotility and abdominal pain, and mucosal eosinophilia is characteristic. We thus aimed to characterise mucosal changes in children with allergic colitis compared with normal tissue and classic IBD, focusing on potential interaction between eosinophils and mast cells with enteric neurones.

METHODS

A total of 15 children with allergic colitis, 10 with Crohn disease (CD), 10 with ulcerative colitis (UC), and 10 histologically normal controls were studied. Mucosal biopsies were stained for CD3 T cells, Ki-67, eotaxin-1, and eotaxin-2. Eotaxin-2, IgE, and tryptase were localised compared with mucosal nerves, using neuronal markers neurofilament protein, neuron-specific enolase, and nerve growth factor receptor.

RESULTS

Overall inflammation was greater in patients with CD and UC than in patients with allergic colitis. CD3 T-cell density was increased in patients with allergic colitis, similar to that in patients with CD but lower than in patients with UC, whereas eosinophil density was higher than in all other groups. Eotaxin-1 and -2 were localised to basolateral crypt epithelium in all specimens, with eotaxin-1+ lamina propria cells found in all of the colitis groups. Eotaxin-2+ intraepithelial lymphocyte (IEL) density was significantly higher in allergic colitis specimens than in all other groups. Mast cell degranulation was strikingly increased in patients with allergic colitis (12/15) compared with that in patients with UC (1/10) and CD (0/1). Tryptase and IgE colocalised on enteric neurons in patients with allergic colitis but rarely in patients with IBD.

CONCLUSIONS

Eotaxin-2+ IELs may contribute to the periepithelial eosinophil accumulation characteristic of allergic colitis. The colocalisation of IgE and tryptase with mucosal enteric nerves is likely to promote the dysmotility and visceral hyperalgesia classically seen in allergic gastrointestinal inflammation.

Eosinophilic colitis in infants

OBJECTIVE

To review the literature for clinical data on infants with allergic or eosinophilic colitis.

DATA SOURCE

MEDLINE search of all indexes was performed using the words "colitis or proctocolitis and eosinophilic" or "colitis or proctocolitis and allergic" between 1966 and February of 2013. All articles that described patients' characteristics were selected.

DATA SYNTHESIS

A total of 770 articles were identified, of which 32 met the inclusion criteria. The 32 articles included a total of 314 infants. According to the available information, 61.6% of infants were male and 78.6% were younger than 6 months. Of the 314 patients, 49.0% were fed exclusively breast milk, 44.2% received cow's milk protein, and 6.8% received soy protein. Diarrheal stools were described in 28.3% of patients. Eosinophilia was found in 43.8% (115/263) of infants. Colonic or rectal biopsy showed infiltration by eosinophils (between 5 and 25 per high-power field) in 89.3% (236/264) of patients. Most patients showed improvement with the removal of the protein in cow's milk from their diet or the mother's diet. Allergy challenge tests with cow's milk protein were cited by 12 of the 32 articles (66 patients).

CONCLUSIONS

Eosinophilic colitis occurs predominantly in the first six months of life and in males. Allergy to cow's milk was considered the main cause of eosinophilic colitis. Exclusion of cow's milk from the diet of the lactating mother or from the infant's diet is generally an effective therapeutic measure.

Milestones in understanding of the pathogenesis of immunmediated intestinal disorders. Development of their diagnosis and therapy

In the last decades our knowledge has been enormously broadened about the structure and function of the gut associated lymphoid system. It was recognized how intricate and finely tuned connection exists between the gut bacterial flora and the intestinal mucosa. This subtle balance ensures mucosal homeostasis, which has a key role in organ defence against pathogens. However, at the same time this system makes possible the development of oral tolerance toward the commensals and the food antigens. In case of any disturbances in this finely tuned process, immunmediated intestinal disorders may easily develop. The first part of this paper reviews the structure and function of the mucosal immune system, while the second part surveys the pathogenesis, diagnosis and therapy of coeliac disease, inflammatory bowel disease and cow’s milk allergy induced enteropathy. Orv. Hetil., 2013, 154, 1512–1523.

Gastrointestinal food allergy in infants

Food allergies are classified into three types, "IgE-mediated," "combined IgE- and cell-mediated" and "cell-mediated/non-IgE-mediated," depending on the involvement of IgE in their pathogenesis. Patients who develop predominantly cutaneous and/or respiratory symptoms belong to the IgE-mediated food allergy type. On the other hand, patients with gastrointestinal food allergy (GI allergy) usually develop gastrointestinal symptoms several hours after ingestion of offending foods; they belong to the cell-mediated/non-IgE-mediated or combined IgE- and cell-mediated food allergy types. GI allergies are also classified into a number of different clinical entities: food protein-induced enterocolitis syndrome (FPIES), food protein-induced proctocolitis (FPIP), food protein-induced enteropathy (Enteropathy) and eosinophilic gastrointestinal disorders (EGID). In the case of IgE-mediated food allergy, the diagnostic approaches and pathogenic mechanisms are well characterized. In contrast, the diagnostic approaches and pathogenic mechanisms of GI allergy remain mostly unclear. In this review, we summarized each type of GI allergy in regard to its historical background and updated clinical features, offending foods, etiology, diagnosis, examinations, treatment and pathogenesis. There are still many problems, especially in regard to the diagnostic approaches for GI allergy, that are closely associated with the definition of each disease. In addition, there are a number of unresolved issues regarding the pathogenic mechanisms of GI allergy that need further study and elucidation. Therefore, we discussed some of the diagnostic and research issues for GI allergy that need further investigation.

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.