Further Insights into the Gut Microbiota of Cow's Milk Allergic Infants: Analysis of Microbial Functionality and Its Correlation with Three Fecal Biomarkers

Cow's milk allergy (CMA) is one of the most prevalent food allergies in children. Several studies have demonstrated that gut microbiota influences the acquisition of oral tolerance to food antigens at initial stages of life. Changes in the gut microbiota composition and/or functionality (i.e., dysbiosis) have been linked to inadequate immune system regulation and the emergence of pathologies. Moreover, omic sciences have become an essential tool for the analysis of the gut microbiota. On the other hand, the use of fecal biomarkers for the diagnosis of CMA has recently been reviewed, with fecal calprotectin, α-1 antitrypsin, and lactoferrin being the most relevant. This study aimed at evaluating functional changes in the gut microbiota in the feces of cow's milk allergic infants (AI) compared to control infants (CI) by metagenomic shotgun sequencing and at correlating these findings with the levels of fecal biomarkers (α-1 antitrypsin, lactoferrin, and calprotectin) by an integrative approach. We have observed differences between AI and CI groups in terms of fecal protein levels and metagenomic analysis. Our findings suggest that AI have altered glycerophospholipid metabolism as well as higher levels of lactoferrin and calprotectin that could be explained by their allergic status.

Fecal Calprotectin and Cow's Milk-Related-Symptoms Score in Children with Cow's Milk Protein Allergy

PURPOSE

The cow's milk-related-symptom-score (CoMiSS) tool was developed as an awareness tool for the assessment of cow's milk-related symptoms in infants or children. Fecal calprotectin (FC) is a noninvasive biomarker of gut inflammation that can be measured in serum and stool. This study aimed to investigate the relationship between FC levels and CoMiSS scores in infants with cow's milk protein allergy.

METHODS

Infants (aged 6-12 months) who were allergic to cow's milk protein were enrolled prospectively. Following completion of the CoMiSS scoring, the infants were divided into group 1 (positive CoMiSS scores ≥12) and group 2 (negative CoMiSS scores <12). FC was measured using immunoassay.

RESULTS

Of the 120 infants enrolled in this study, 60 (50.0%) had positive CoMiSS scores (group 1), while 60 (50.0%) had negative scores (group 2). The mean FC level was higher in the infants in group 1 than those in group 2 (2,934.57 µg/g vs. 955.13 µg/g; p<0.001). In addition, there was a positive correlation between FC and CoMiSS scores (R=0.168, p<0.0001). A FC level of 1,700 µg/g provided a sensitivity of 98.3%, specificity of 93.3%, and accuracy of 95.8% for the diagnosis of cow's milk protein allergy (CMPA).

CONCLUSION

FC measurement may have a role in the assessing infants with CMPA.

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.

Fecal Calprotectin and Eosinophil-Derived Neurotoxin in Children with Non-IgE-Mediated Cow's Milk Protein Allergy

Our aim is to assess the efficacy of fecal calprotectin (fCP) and fecal eosinophil-derived neurotoxin (fEDN) as diagnostic markers of cow's milk protein allergy (CMPA) and for monitoring the infants' response to a non-IgE mediated cow's milk protein (CMP)-free diet. We prospectively recruited infants aged 0 to 9 months. Stool samples were taken from 30 infants with CMPA, 19 with mild functional gastrointestinal disorders, 28 healthy infants, and 28 children who presented mild infections. Despite the fact that levels of fCP and fEDN in CMPA infants were higher than in healthy infants at month 0, differences for both parameters did not reach statistical significance (p-value 0.119 and 0.506). After 1 month of an elimination diet, no statistically significant differences in fCP with basal levels were found (p-values 0.184) in the CMPA group. We found a high variability in the fCP and fEDN levels of young infants, and discrepancies in individual behavior of these markers after a CMP-free diet was started. It seems that neither fCP nor fEDN levels are helpful to discriminate between healthy infants and those with signs or symptoms related to non-IgE-mediated CMPA. Additionally, it is debatable if on an individual basis, fCP or fEDN levels could be used for clinical follow-up and dietary compliance monitoring. However, prospective studies with larger populations are needed to draw robust conclusions.

The Use of Fecal Calprotectin Testing in Paediatric Disorders: A Position Paper of the European Society for Paediatric Gastroenterology and Nutrition Gastroenterology Committee

OBJECTIVES

The aim of the study was to review the evidence regarding the clinical use and value of fecal calprotectin (FC) measurements in different gastrointestinal disorders in children.

METHODS

A literature search was conducted in the PubMed, MEDLINE, EMBASE, and Cochrane databases until October 31, 2019. Subtopics were identified and each assigned to individual authors.

RESULTS

A total of 28 recommendations were voted on using the nominal voting technique. Recommendations are given related to sampling, measurement methods, and results interpretation. The 14 authors anonymously voted on each recommendation using a 9-point scale (1 strongly disagree to 9 fully agree). Consensus was considered achieved if at least 75% of the authors voted 6, 7, 8, or 9.

CONCLUSIONS

Consensus was reached for all recommendations. Limitations for the use of FC in clinical practice include variability in extraction methodology, performance of test kits as well as the need to establish local reference ranges because of the influence of individual factors, such as age, diet, microbiota, and drugs. The main utility of FC measurement at present is in the diagnosis and monitoring of inflammatory bowel disease (IBD) as well as to differentiate it from functional gastrointestinal disorders (FAPDs). FC, however, has neither utility in the diagnosis of infantile colic nor to differentiate between functional and organic constipation. A rise in FC concentration, may alert to the risk of developing necrotizing enterocolitis and help identifying gastrointestinal involvement in children with Henoch-Schönlein purpura. FC measurement is of little value in Cow's Milk Protein Allergy, coeliac disease (CD), and cystic fibrosis. FC does neither help to distinguish bacterial from viral acute gastroenteritis (AGE), nor to diagnose Helicobacter Pylori infection, small intestinal bacterial overgrowth (SIBO), acute appendicitis (AA), or intestinal polyps.

Current status of fecal calprotectin as a diagnostic or monitoring biomarker for cow's milk protein allergy in children: a scoping review

BACKGROUND

There are few approved biomarkers for diagnosis and monitoring of cow's milk protein allergy (CMPA), thus the oral food challenge remains to be the golden diagnostic standard. A potential biomarker is fecal calprotectin, a cytosolic protein, elevating in the presence of intestinal mucosal inflammation. We aimed to undertake a scoping review of the evidence pertaining to the current status of fecal calprotectin used for diagnosis and monitoring CMPA in children, and tried to indicate the aspects needed to be concerned in the future investigations and researches.

METHODS

A scoping review was performed using the literature searched from PUBMED, EMBASE, and Web of Science Databases until July 2019 on the studies about the application of fecal calprotectin as a biomarker of CMPA in children. Studies were examined according to the inclusion and exclusion criteria. Data were extracted, and a narrative synthesis was conducted to summarize and analyze.

RESULTS

Thirteen studies with different study design embracing 1238 children were included. The age range was from infants to adolescents. Most children with CMPA presented gastrointestinal symptoms, among which hematochezia was most common. Amount of data suggested that infants with CMPA represented elevated levels of fecal calprotectin, particularly with distinct significance in non-IgE-mediated CMPA groups. Decreases of fecal calprotectin after elimination diet were demonstrated in enrolled studies. However, no matter in the CMPA positive or negative groups, the changes of fecal calprotectin before or after challenge showed no significance. Contradictory results were generated from studies on the role of fecal calprotectin in predicting allergic disease.

CONCLUSIONS

Available evidence is not sufficient to confirm the utilization of fecal calprotectin both in diagnosis and monitoring of CMPA and predicting for allergic disease. More clinical and bench researches with elaborate design should be conducted and the exact cut-off values of fecal calprotectin in different groups remain to be determined.

Non-IgE- or Mixed IgE/Non-IgE-Mediated Gastrointestinal Food Allergies in the First Years of Life: Old and New Tools for Diagnosis

non-IgE and mixed gastrointestinal food allergies present various specific, well-characterized clinical pictures such as food protein-induced allergic proctocolitis, food protein-induced enterocolitis and food protein-induced enteropathy syndrome as well as eosinophilic gastrointestinal disorders such as eosinophilic esophagitis, allergic eosinophilic gastroenteritis and eosinophilic colitis. The aim of this article is to provide an updated review of their different clinical presentations, to suggest a correct approach to their diagnosis and to discuss the usefulness of both old and new diagnostic tools, including fecal biomarkers, atopy patch tests, endoscopy, specific IgG and IgG4 testing, allergen-specific lymphocyte stimulation test (ALST) and clinical score (CoMiss).

Eosinophil-Derived Neurotoxin, Tumor Necrosis Factor Alpha, and Calprotectin as Non-Invasive Biomarkers of Food Protein-Induced Allergic Proctocolitis in Infants

Diagnosis of non-IgE mediated food allergy presents a special challenge due to lack of a single, non-invasive diagnostic method. We selected three fecal biomarkers of allergic inflammation of gastrointestinal origin in order to improve the diagnostic process. Twenty-seven infants with symptoms of hematochezia were prospectively enrolled into this study. All patients underwent a complete differential diagnosis of rectal bleeding. Non-IgE mediated food allergy was confirmed by an open, oral food challenge. The control group included twenty-five infants with functional gastrointestinal disorders. Eosinophil-derived neurotoxin (EDN), tumor necrosis factor alpha (TNFα), and calprotectin concentration were measured in stools of all children by enzyme-linked immunosorbent assays (ELISA) using commercial kits. Median eosinophil-derived neurotoxin and calprotectin fecal levels were significantly higher in the study group than in the control group (p < 0.05). The difference of fecal tumor necrosis factor alpha concentration between both groups was not statistically significant (p > 0.05). The best diagnostic performance was reached in a combination of fecal calprotectin (fCal) and EDN i.e., 88.9% and 84%, respectively. Fecal EDN and fCAl are reliable tools in differentiating between food protein-induced allergic proctocolitis and gastrointestinal functional disorders in infants.

Probiotics for cow's milk protein allergy: a systematic review of randomized controlled trials

Cow's milk protein allergy (CMPA) is the commonest food allergy in infancy and is associated with significant health burden. Given their immune modulatory properties, probiotics have been proposed as a strategy for management of CMPA. We aimed to systematically review efficacy and safety of probiotics in the management of CMPA. Databases PubMed, EMBASE, CINAHL, Cochrane Central Library, and Google scholar were searched in August 2018 for randomized controlled trials (RCT) of probiotic supplementation as an adjunct in the management of infants with suspected/proven CMPA. Primary outcomes were resolution of hematochezia and acquisition of tolerance to CMP at 6, 12, 24, and 36 months. Secondary outcomes included effect on allergic symptoms (SCORAD index), growth, gut microbiota, and adverse effects. A total of 10 RCTs (n = 845; probiotics, 422; control, 423) with low to unclear risk of bias were included. Meta-analysis showed probiotic supplementation was not associated with earlier resolution of hematochezia (n = 87; RR: 1.45 (95% CI: 0.96-2.18), p = 0.08; level of evidence (LOE), very low), in presumed CMPA. In confirmed CMPA, probiotics were associated with higher rate of acquisition of tolerance to CMP at the end of 3 years compared with placebo (N = 493; RR, 1.47; 95% CI, (1.17-1.84); p = 0.0009; LOE, low]. Meta-analysis was not possible for other outcomes. There were no probiotic related adverse effects. Conclusion: Limited low-quality evidence indicates that probiotic supplementation may be associated with earlier acquisition of tolerance to CMP in children with CMPA. Large well-designed trials are essential to confirm these findings. What is Known: • Cow's milk protein allergy (CMPA) is one of the commonest food allergies in children. CMPA is associated with significant socioeconomic burden. • Elimination diet and extensively hydrolyzed formula is the mainstay of the management of CMPA. What is New: • This first systematic review of randomized controlled trials shows that probiotics as an adjuvant can lead to earlier acquisition of tolerance to CMP in children at 36 months of age. However, the evidence is low quality and influenced by data from one large study. • Probiotic supplementation was not associated with earlier resolution of hematochezia.