Factors that predict the clinical reactivity and tolerance in children with cow's milk allergy

Systematic review and meta-analyses on the accuracy of diagnostic tests for IgE-mediated food allergy

The European Academy of Allergy and Clinical Immunology (EAACI) is updating the Guidelines on Food Allergy Diagnosis. We aimed to undertake a systematic review of the literature with meta-analyses to assess the accuracy of diagnostic tests for IgE-mediated food allergy. We searched three databases (Cochrane CENTRAL (Trials), MEDLINE (OVID) and Embase (OVID)) for diagnostic test accuracy studies published between 1 October 2012 and 30 June 2021 according to a previously published protocol (CRD42021259186). We independently screened abstracts, extracted data from full texts and assessed risk of bias with QUADRAS 2 tool in duplicate. Meta-analyses were undertaken for food-test combinations for which three or more studies were available. A total of 149 studies comprising 24,489 patients met the inclusion criteria and they were generally heterogeneous. 60.4% of studies were in children ≤12 years of age, 54.3% were undertaken in Europe, ≥95% were conducted in a specialized paediatric or allergy clinical setting and all included oral food challenge in at least a percentage of enrolled patients, in 21.5% double-blind placebo-controlled food challenges. Skin prick test (SPT) with fresh cow's milk and raw egg had high sensitivity (90% and 94%) for milk and cooked egg allergies. Specific IgE (sIgE) to individual components had high specificity: Ara h 2-sIgE had 92%, Cor a 14-sIgE 95%, Ana o 3-sIgE 94%, casein-sIgE 93%, ovomucoid-sIgE 92/91% for the diagnosis of peanut, hazelnut, cashew, cow's milk and raw/cooked egg allergies, respectively. The basophil activation test (BAT) was highly specific for the diagnosis of peanut (90%) and sesame (93%) allergies. In conclusion, SPT and specific IgE to extracts had high sensitivity whereas specific IgE to components and BAT had high specificity to support the diagnosis of individual food allergies.

‘Early Introduction’ of Cow’s Milk for Children with IgE-Mediated Cow’s Milk Protein Allergy: A Review of Current and Emerging Approaches for CMPA Management

IgE-mediated cow’s milk protein allergy (CMPA) is one of the most prevalent food allergies in early childhood. Though the cornerstone of management involves the strict avoidance of milk products while awaiting natural tolerance, research increasingly shows that the rates of resolution are slowing down. Therefore, there is a need to explore alternative pathways to promote tolerance to cow’s milk in pediatric populations. This review aims to combine and appraise the scientific literature regarding the three CMPA management methods: avoidance, the milk ladder, and oral immunotherapy (OIT) and their outcomes in terms of efficacy, safety, and immunological effects. Cow’s milk (CM) avoidance virtually protects against allergic reaction until natural tolerance occurs, with hypoallergenic substitutes available in the market, but accidental ingestion represents the main issue for this strategy. Introduction to baked milk using the milk ladder was designed, with most CMPA patients successfully completing the ladder. Similar to baked milk treatment, many OIT protocols also demonstrated decreased IgE and increased IgG4 levels post protocol, as well as a reduction in wheal size diameter. Though these strategies are shown to be safe and effective in CMPA, future clinical trials should compare the safety and effectiveness of these three management strategies.

Molecular allergy diagnostics in predicting oral cow's milk challenge outcome in Finnish children

Background: Oral food challenges (OFC) are required to diagnose food allergies but are resource-intensive. Objective: To reduce the need for OFCs, we sought to determine serum specific immunoglobulin E (sIgE) cutoff levels for cow's milk and its major allergens predicting oral milk challenge outcomes in children with suspected cow's milk allergy. Methods: A total of 135 Finnish children (median age, 1.8 years [range, 1.0-14.1 years]) with suspected cow's milk allergy underwent open OFC with unheated cow's milk. The sIgE levels to milk (f2), casein (Bos d 8), alpha-lactalbumin (Bos d 4), beta-lactoglobulin (Bos d 5), and bovine serum albumin (BSA) (Bos d 6) were measured and compared with the challenge outcomes. Results: Of the 135 OFCs, 5 were excluded from the study due to purely subjective symptoms. Of the 130 remaining OFCs, 98 results (75%) were positive. In a receiver operating characteristic analysis with 1-2-year-old children, no individual allergen sIgE had a better area under the curve than milk sIgE (0.824). A milk sIgE level > 6.30 kU/L gave 94% specificity and 33% sensitivity for positive OFCs. In 3-14-year-old children, a cutoff value >13.9 kU/L predicted a positive OFC result with 93% specificity and 25% sensitivity. Children with moderate-to-severe reactions had higher sIgE levels to milk, alpha-lactalbumin, and BSA than did children with mild reactions. Conclusion: Molecular allergy diagnostics did not improve the predictive performance compared with milk sIgE. The milk sIgE value that exceeds the cutoff for 95% specificity in combination with the clinical history may help to reduce the need for OFCs. The severity of an allergic reaction cannot reliably be predicted from sIgE measurements.

Frequency distribution of cytokine and associated transcription factor single nucleotide polymorphisms in Zimbabweans: Impact on schistosome infection and cytokine levels

Cytokines mediate T-helper (TH) responses that are crucial for determining the course of infection and disease. The expression of cytokines is regulated by transcription factors (TFs). Here we present the frequencies of single nucleotide polymorphisms (SNPs) in cytokine and TF genes in a Zimbabwean population, and further relate SNPs to susceptibility to schistosomiasis and cytokine levels. Individuals (N = 850) were genotyped for SNPs across the cytokines IL4, IL10, IL13, IL33, and IFNG, and their TFs STAT4, STAT5A/B, STAT6, GATA3, FOXP3, and TBX21 to determine allele frequencies. Circulatory levels of systemic and parasite-specific IL-4, IL-5, IL-10, IL-13, and IFNγ were quantified via enzyme-linked immunosorbent assay. Schistosoma haematobium infection was determined by enumerating parasite eggs excreted in urine by microscopy. SNP allele frequencies were related to infection status by case-control analysis and logistic regression, and egg burdens and systemic and parasite-specific cytokine levels by analysis of variance and linear regression. Novel findings were i) IL4 rs2070874*T’s association with protection from schistosomiasis, as carriage of ≥1 allele gave an odds ratio of infection of 0.597 (95% CIs, 0.421–0.848, p = 0.0021) and IFNG rs2069727*G’s association with susceptibility to schistosomiasis as carriage of ≥1 allele gave an odds ratio of infection of 1.692 (1.229–2.33, p = 0.0013). Neither IL4 rs2070874*T nor IFNG rs2069727*G were significantly associated with cytokine levels. This study found TH2-upregulating SNPs were more frequent among the Zimbabwean sample compared to African and European populations, highlighting the value of immunogenetic studies of African populations in the context of infectious diseases and other conditions, including allergic and atopic disease. In addition, the identification of novel infection-associated alleles in both TH1- and TH2-associated genes highlights the role of both in regulating and controlling responses to Schistosoma.

Predictive Factors for Oral Immune Modulation in Cow Milk Allergy

Aim: The present study analyzed clinical and biological factors that might predict achievement of tolerance in patients with IgE-mediated cow milk allergy (CMA). Method: Seventy patients with IgE-mediated CMA (44.24 ± 24.16 months) were included in the study. The patients were evaluated clinically through skin prick test and sIgE to whole milk, casein, beta-lactoglobulin and alpha-lactalbumin. An eviction diet of 6 months was established, followed by oral food challenge test (OFC) and oral immunotherapy (OIT) with baked milk for 6 months. The tolerance was assessed after 2 years follow up. Results: Thirty percent of patients presented anaphylaxis of different degrees of severity as first manifestation of CMA. Sixty-two patients followed OIT or an accelerated reintroduction of milk. Ten patients (14.28%) did not obtain tolerance to milk within 2 years. A larger wheal in SPT and higher sIgE to milk, casein and betalactoglobulin were noted in patients with positive OFC. A basal level of <2.5 kU/l for sIgE to milk and <11.73 kU/l for sIgE to caseins predicted the occurrence of tolerance in patients with all types of clinical manifestations, including anaphylaxis. Conclusion: Basal levels of sIgE to milk and casein may help to identify patients that could become tolerant to milk.

Potential Biomarkers, Risk Factors and their Associations with IgE-mediated Food Allergy in Early Life: A Narrative Review

Food allergy affects the quality of life of millions of people worldwide and presents a significant psychological and financial burden for both national and international public health. In the past few decades, the prevalence of allergic disease has been on the rise worldwide. Identified risk factors for food allergy include family history, mode of delivery, variations in infant feeding practices, prior diagnosis of other atopic diseases such as eczema, and social economic status. Identifying reliable biomarkers which predict the risk of developing food allergy in early life would be valuable in both preventing morbidity and mortality and by making current interventions available at the earliest opportunity. There is also the potential to identify new therapeutic targets. This narrative review provides details on the genetic, epigenetic, dietary and microbiome influences upon the development of food allergy and synthesizes the currently available data indicating potential biomarkers. While there is a large body of research evidence available within each field of potential risk factors, there are very limited number of studies which span multiple methodological fields, for example including immunology, microbiome, genetic/epigenetic factors and dietary assessment. We recommend that further collaborative research with detailed cohort phenotyping is required to identify biomarkers, and whether these vary between at-risk populations and the wider population. The low incidence of oral food challenge confirmed food allergy in the general population, and the complexities of designing nutritional intervention studies will provide challenges for researchers to address in generating high quality, reliable and reproducible research findings.

STATEMENT OF SIGNIFICANCE

Food allergy affects the quality of life of millions of people worldwide and presents a significant psychological and financial burden for both national and international public health. Identifying reliable biomarkers which predict the risk of developing food allergy would be valuable in both preventing morbidity and mortality and by making current interventions available at the earliest opportunity. This review provides details on the genetic, epigenetic, dietary and microbiome influences upon the development of food allergy. This helps in identifying reliable biomarkers to predict the risk of developing food allergy, which could be valuable in both preventing morbidity and mortality and by making interventions available at the earliest opportunity.

Prevalence, Risk Factors, Clinical Manifestation, Diagnosis Aspects and Nutrition Therapy in Relation to both IgE and IgG Cow’s Milk Protein Allergies among a Population of Saudi Arabia: A Literature Review

Cow milk protein allergy (CMPA) becoming a major public health issue that has attracted the attention of health professionals and researchers. This paper aimed to review the important aspects of both IgE and IgG types of cow’s milk protein allergy in terms of prevalence, clinical manifestation, risk factors, other health-related issues and nutritional therapy proposed for such allergies in the adult and pediatric population in Saudi Arabia. A search on “cow’s milk allergy” was done using PubMed, Google Scholar and Scopus Engine for published papers between 1993 and 2020 to find studies yielding knowledge on that context. The prevalence of cow’s milk protein allergy (CMPA) among infants is now in the range of 2–3%. This type of allergy is also detected in adulthood but less frequently. CMPA is defined as an immunological reaction to specific proteins in milk. CMPA is classified based on its type as an immunoglobulin E (IgE)-mediated form and an immunoglobulin G (IgG)-mediated form, each type representing different immunological pathways. The presence of Genetic aspects, family history and short duration of breastfeeding in the infant are among the risk factors contributing to this form of allergy. Its manifestations mainly present as skin presentation, followed by the gastrointestinal and respiratory presentation in most cases in addition to a life-threatening anaphylactic reaction that may occur in 12% of cases. food allergy committees have developed strict diagnosis criteria, including blood testing for food-specific immunoglobulin E (sIgE), a skin prick test and double-blind placebo-controlled food challenges (DBPCFC) as the gold standard. A diet free of cow’s milk protein (CMP) allergen and including the appropriate alternative milk formula is the first line of prevention recommended by many organizations and food allergy experts. As for Saudi Arabia, more research and clinical trials are required to discuss the various aspects of adult and pediatric CMPA and to provide a better understanding along with good control strategies implementation.

Cow's Milk Protein Allergy as a Model of Food Allergies

Cow's milk allergy (CMA) is one of the most common food allergies in infants, and its prevalence has increased over recent years. In the present paper, we focus on CMA as a model of food allergies in children. Understanding the diagnostic features of CMA is essential in order to manage patients with this disorder, guide the use of an elimination diet, and find the best moment to start an oral food challenge (OFC) and liberalize the diet. To date, no shared tolerance markers for the diagnosis of food allergy have been identified, and OFC remains the gold standard. Recently, oral immunotherapy (OIT) has emerged as a new therapeutic strategy and has changed the natural history of CMA. Before this, patients had to strictly avoid the food allergen, resulting in a decline in quality of life and subsequent nutritional, social, and psychological impairments. Thanks to the introduction of OIT, the passive approach involving rigid exclusion has changed to a proactive one. Both the heterogeneity in the diagnostic process among the studies and the variability of OIT data limit the comprehension of the real epidemiology of CMA, and, consequentially, its natural history. Therefore, well-planned randomized controlled trials are needed to standardize CMA diagnosis, prevention, and treatment strategies.

IgE-mediated food allergy throughout life

Food allergy (FA) has become an increasing problem throughout the world. Over the last 2 decades, the frequency of FA has increased in both children and adults. The prevalence differs according to the research methodology, age, and geographic regions, ranging between 2.0% and 10.0%. The most common form of FA is immunoglobulin E (IgE)-mediated FA. In this form, patients may present with life-threatening conditions, such as anaphylaxis, or milder conditions, such as urticaria, angioedema, sneezing, and nausea alone. The gold standard in the diagnosis of FA is oral provocation tests. Epidermal skin prick tests and specific IgE measurements, as well as component-resolved diagnostic techniques are helpful in the diagnosis and follow-up of patients. In this review, the epidemiology, diagnosis, follow-up, and prognosis of IgE-mediated FA in children and adults were discussed and some specific forms of FA, such as pollen FA syndrome, alpha-gal allergy, and food-dependent exercise-induced anaphylaxis were explained.

Precision medicine in cow's milk allergy

PURPOSE OF REVIEW

The aim of this review is to describe the role of precision medicine in the diagnosis, treatment, and monitoring of cow's milk allergy.

RECENT FINDINGS

The development of 'omics' sciences in the field of food allergy has led to a better understanding of the allergenicity of cow's milk proteins and significant advances in the knowledge of the pathogenesis and mechanisms of cow's milk allergy. Omics-based technologies allow the practitioner to better differentiate cow's milk allergy subtypes and to predict cow's milk allergy (CMA) persistence over time. Precision medicine extends the role of the oral food challenge, to determine the individual's threshold doses, and to establish tolerance to baked milk products. Other than symptom relief, dietary strategies are currently being investigated for the potential to induce tolerance. Oral immunotherapy offers a treatment option for patients with severe and persistent IgE-mediated CMA. Individual baseline-immune profiles may be predictive of cow's milk oral immunotherapy safety and efficacy.Patient data derived from current technology, in combination with the patient's history, can be translated into treatments targeted at patient-tailored interventions.

SUMMARY

The identification of novel biomarkers may improve diagnostic accuracy and also predict patient responsiveness to treatments. Integration of patient data will become increasingly important as omics technologies become more widely used in the clinical setting.

The Natural Course of Immediate-Type Cow's Milk and Egg Allergies in Children

BACKGROUND

Most of children with cow's milk (CM) and hen's egg allergies are known to outgrow their diseases with time, but recent studies have demonstrated that children tend to continue to have allergic symptoms in adolescence and adulthood. The aim of this study was to investigate the natural course of CM and egg allergies in Korean children and analyze prognostic factors.

METHODS

In this retrospective study, we reviewed data of children with CM allergy and with egg allergy using medical records and parental telephone interviews. Diagnosis of CM or egg allergy was based on positive oral food challenge test or convincing history of allergic symptoms in combination with positive allergen-specific IgE. Acquisition of tolerance was defined by the absence of allergic symptoms after reintroduction of the offending foods.

RESULTS

Half of the children outgrew CM allergy at a median age of 8.7 years. CM-specific IgE level at the first reaction was a significant prognostic factor for oral tolerance in CM allergy (p < 0.05). The median age to acquire oral tolerance in 50% of patients with egg allergy was 5.6 years. Egg-specific IgE level at the first reaction and family history of allergic diseases significantly affected the prognosis in children with egg allergy (p < 0.05).

CONCLUSIONS

Half of Korean children with CM and egg allergies had symptom resolution at 8.7 and 5.6 years of age, respectively. Our results also suggest that CM- and egg-specific IgE levels at the first reaction are the most significant prognostic factors in predicting acquisition of oral tolerance.

Predicting outgrowth of IgE-mediated cow's milk allergy: Diagnostic tests in children under two years of age

BACKGROUND

Limited studies conducted on children <2 years old and/or involving a skin prick test (SPT) for fresh milk (FM) have examined the predictive value of allergometric tests for outgrowth of cow's milk allergy (CMA). We investigated the optimal decision points for outgrowth (ODP^fo) with SPT for commercial cow's milk extract (CE) and FM and specific immunoglobulin E (sIgE) levels for milk proteins to predict outgrowing allergy in children <2 years old.

METHODS

SPTs for CE and FM, tests for sIgEs (cow's milk, casein, α-lactoalbumin, β-lactoglobulin) and oral food challenges (OFC) were performed in children referred for evaluation of suspected CMA, and 15 months after diagnosis.

RESULTS

Fifty-one children (median age, 7.5 months; range, 2-23 months) were enrolled. Five had a history of anaphylaxis and 26 of 48 children with a positive initial challenge underwent milk elimination. The last OFC was performed in 28 children of whom 13 reacted to milk. The initial SPT responses to CE and FM and milk sIgE levels of the patients with persistent CMA were higher at diagnosis, with ODP^fo of 7mm, 9mm, and 10.5kU/L, respectively; these values remained higher with ODP^fo of 4mm, 11mm, and 10.5kU/L at the last OFC.

CONCLUSION

Higher initial SPTs for FM and CE and higher initial sIgE levels for cow's milk proteins are associated with a reduced likelihood of outgrowth. Initial milk sIgE level <10.5kU/L and initial SPT for fresh milk <9mm are related to the acquisition of tolerance in the follow-up period.

Association of STAT6 gene variants with food allergy diagnosed by double-blind placebo-controlled food challenges

This study describes the role of two STAT6 gene variants in food allergy using data of patients and their parents who underwent double‐blind placebo‐controlled food challenges (DBPCFCs). After quality control, 369 trios were analysed including 262 children (71.0%) with food allergy. Associations were tested by the Family based association test. The A alleles of both SNPs were associated with food allergy (P = .036 and P = .013 for rs324015 and rs1059513, respectively). Furthermore, these A alleles were associated with peanut allergy, higher sIgE levels to both peanut and cow's milk, more severe symptoms and higher eliciting doses during peanut and cow's milk DBPCFCs (all P < .05). In silico analysis indicates that the identified risk variants increase STAT6 expression which stimulates the differentiation of CD4 +  T cells to the Th2 subset. In conclusion, STAT6 variants may be involved in the pathophysiology of food allergy and their role seems to be independent of the allergenic food.

Milk-Related Symptoms and Immunoglobulin E Reactivity in Swedish Children from Early Life to Adolescence

Cow&rsquo;s milk often causes symptoms in infants. Whereas, some continue to experience symptoms through childhood, others become tolerant. Yet, the ages at which persistence and tolerance occur are less clear. Thus, we examined the age of onset and persistence of milk-related symptoms from early life to adolescence, and Immunoglobulin E (IgE) milk reactivity, focusing on gender differences in a large, population-based birth cohort. Overall, 20.0% (537/2985) of children, with a comparable gender distribution, had early life milk-related symptoms. At 16y, approximately 2% (62/2985) children had persistent symptoms and high milk IgE levels (e.g., median at 4 years: 1.5 kU_A/L) that were beginning in early life. In contrast, 94% had transient symptoms and low median IgE levels (early life: 0.63 kU_A/L, 8y: 0.72 kU_A/L; 16 years: 1.1 kU_A/L). Also, at 16 years, approximately 6% of females and 3% of males without any previously reported symptoms reported adolescent-onset of symptoms (p < 0.001). Such symptoms were almost exclusively gastrointestinal symptoms and were not associated with detectable IgE. In conclusion, early life milk-related symptoms are common, although most cases are transient by 16 years. Twice as many females vs. males report adolescent-onset symptoms, and particularly gastrointestinal symptoms. Children with persistent symptoms have both a higher prevalence and higher milk IgE levels, as compared to other phenotypes.

Cow's milk allergic children-Can component-resolved diagnostics predict duration and severity?

BACKGROUND

Cow's milk allergy (CMA) affects 2% of all children. This study investigatescomponent-resolved diagnostics(CRD) to cow's milk proteins in children suspected of CMA, by correlating the level of CRD with outcome of the oral challenge. Furthermore, we evaluate the ability of serial CRD measurements to distinguish children with persistent CMA from children developing tolerance.

METHODS

We included data from 78 children referred to the Allergy Centre during a 13-year period. Results from oral food challenges including threshold, severity, and sensitization data (IgE antibodies to whole milk protein, IgE components toward milk and skin prick test (SPT)) were collected. The milk allergic children were re-evaluated with sensitization data and rechallenges regularly.

RESULTS

Thirty-nine children had negative first challenges, and 39 had positive first challenges. The positive group was rechallenged and separated into 3 groups depending on time to remission. At inclusion, children with persistent CMA had significantly larger size of SPT and higher levels of s-IgE to milk and CRD compared to the other groups. SPT wheal size was significantly larger in children with persistent CMA compared to children outgrowing CMA. Furthermore, a correlation between s-IgE level to cow's milk and casein and the severity of the allergic reaction elicited by food challenges was found.

CONCLUSION

Oral food challenge cannot be replaced by s-IgE to whole milk protein or milk components nor SPT in the diagnosis of CMA; however, high levels of milk components and s-IgE to milk increase the risk of a long-lasting or persisting CMA.

Are genetic tests informative in predicting food allergy?

PURPOSE OF REVIEW

Food allergy is common among children and adults worldwide. Recent studies have improved our understanding of the genetic mechanism of food allergy and further studies may result in clinical application through genetic testing.

RECENT FINDINGS

Genetic factors are important in the development of food allergy. An increasing number of genes have been associated with food allergy in recent years. These include mutations and genetic variants in the filaggrin gene, the association of human leukocyte antigen DR and DQ regions with food allergy, copy number variation impacting CTNNA3 and RBFOX1, DNA methylation that partially mediates single nucleotide polymorphism association at the HLA-DR and DQ loci, as well as other genes. Several studies have implicated differences in gut microbiota composition in food allergy.

SUMMARY

With the advance of high-throughput genotyping and sequencing techniques together with improved analytical methods, the contributions of genetic and environmental factors in development of food allergy are being clarified. Yet much remains to be explored and more studies with larger sample sizes, better phenotyping, and improved quality control genomics methods are needed. The ultimate goal is the development of a panel of reliable markers for genetic testing in food allergy to improve overall patient care.

The Prevalence and Natural History of Food Allergy

Numerous studies have demonstrated that the prevalence of food allergy is increasing. Not only are more children being diagnosed with food allergies, but studies suggest that when people outgrow their food allergies, it is taking longer than was previously thought. Studies in recent years have noted factors that may lead to a lower likelihood of developing a food allergy, including the early introduction of common food allergens, having a sufficient vitamin D level, or having a higher maternal intake of peanut early in pregnancy. Given a recent report that sensitization to common food allergens did not increase from the late 1980s/early 1990s to the mid-2000s, further studies will need to examine if the rise in food allergy prevalence is due to a change in the relationship between sensitization and clinical allergy or changes in the recognition and diagnosis of food allergy.

Food-Related Symptoms and Food Allergy in Swedish Children from Early Life to Adolescence

Background

Risk factors for persistence of food-related symptoms (FRS) and food allergy (FA) from early life to adolescence are incompletely understood. The aim of this study was to identify risk factors for FRS and FA in adolescence amongst children with FRS or FA in the first four years of life (early life).

Methods

In children enrolled in a Swedish birth cohort and followed to 16 years (n = 2572), we defined children with early life FRS in the absence of FA, and FA. Corresponding phenotypes were defined at 16 years. Associations between potential risk factors at 4 years and FRS and FA at 16 years were investigated using logistic regression.

Results

Early life FRS and FA prevalences were 12.2% and 6.8%, respectively. Amongst children with early life FRS, 35.7% had FRS or FA at 16 years, whereas 74.3% of the children with early life FA had FA at 16 years. For each of the early life phenotypes, parental allergy, early life allergic multimorbidity, early life reactions to peanuts/tree nuts and IgE reactivity at 4 years were statistically significantly associated with FRS or FA at 16 years. In contrast, male sex was associated with an increased risk of FA at 16 years among children with early life FA only.

Conclusions

In early life, food-related symptoms are twice as common as food allergy. Unlike food allergy, food-related symptoms often remit by adolescence. Yet, these phenotypes have many common risk factors for persistence to adolescence.

Cow's Milk Protein Allergy

Cow's milk protein allergy (CMPA) is a common condition encountered in children with incidence estimated as 2% to 7.5% in the first year of life. Formula and breast-fed babies can present with symptoms of CMPA. It is important to accurately diagnose CMPA to avoid the consequences of either under- or overdiagnosis. CMPA is classically categorized into immunoglobulin E (IgE)- or non-IgE-mediated reaction that vary in clinical manifestations, diagnostic evaluation, and prognosis. The most commonly involved systems in patients with CMPA are gastrointestinal, skin, and respiratory. Evaluation of CMPA starts with good data gathering followed by testing if indicated. Treatment is simply by avoidance of cow's milk protein (CMP) in the child's or mother's diet, if exclusively breast-feeding. This article reviews the definition, epidemiology, risk factors, pathogenesis, clinical presentation, evaluation, management, and prognosis of CMPA and provides an overview of different options for formulas and their indication in the treatment of CMPA.

Food Allergy in childhood: phenotypes, prevention and treatment

The prevalence of food allergy in childhood increased in the last decades, especially in Westernized countries where this phenomenon has been indicated as a second wave of the allergic epidemic. In parallel, scientific interest also increased with the effort to explain the reasons of this sudden rise and to identify potential protective and risk factors. A great attention has been focused on early exposures to allergenic foods, as well as on other nutritional factors or supplements that may influence the immune system in a positive direction. Both interventions on maternal diet before birth or during breastfeeding and then directly on infant nutrition have been investigated. Furthermore, the natural history of food allergy also seems to be changing over time; IgE-mediated cow's milk allergy and egg allergy seem to be more frequently a persistent rather than a transient disease in childhood, as described in the last years. Food avoidance and the emergency drugs in case of an adverse event, such as epinephrine self-injector, are currently the first-line treatment in patients with food allergies, with a resulting impairment in the quality of life and social behaviour. During the last decade, oral immunotherapy emerged as an optional treatment with remarkable results, offering a novel perspective in the treatment for and management of food allergy.

Food allergy: epidemiology and natural history

The prevalence of food allergy is rising for unclear reasons, with prevalence estimates in the developed world approaching 10%. Knowledge regarding the natural course of food allergies is important because it can aid the clinician in diagnosing food allergies and in determining when to consider evaluation for food allergy resolution. Many food allergies with onset in early childhood are outgrown later in childhood, although a minority of food allergy persists into adolescence and even adulthood. More research is needed to improve food allergy diagnosis, treatment, and prevention.

Casein-specific IL-4- and IL-13-secreting T cells: a tool to implement diagnosis of cow's milk allergy

BACKGROUND

Cow's milk allergy (CMA) is a frequent food allergy in young children. The oral food challenge is the gold standard for diagnosis, and there is currently no reliable biological test. Our aim was to evaluate the diagnostic potential of a functional assay quantifying allergen-specific Th2 cells in CMA children.

METHODS

A total of 29 children aged 2.8-10.5 years underwent a double-blind, placebo-controlled food challenge (DBPCFC) to cow's milk. Blood was collected before performing the DBPCFC, and peripheral mononuclear cells were cultured in an 18-h ELISpot assay with casein, α-lactalbumin, or β-lactoglobulin. Numbers of antigen-specific IL-4- and IL-13-secreting lymphocytes and serum-specific IgE, IgG4, and total IgE levels were assessed. Receiver operating characteristic (ROC) curves were generated.

RESULTS

A total of 17 (59%) children reacted to cow's milk and were therefore considered as allergic to cow's milk (CMA). The mean number of casein-specific IL-4- and IL-13-secreting T cells was higher in CMA than in non-CMA children (P = 0.009, 0.004, respectively). Moreover, it was inversely correlated with the cumulative dose of cow's milk tolerated (P = 0.003, 0.0009, respectively). ROC curve of combined IL-4 and IL-13 analysis showed an area under the curve of 0.98 (95% CI 0.90-1.06). For a cutoff of 10 IL-4- and 12 IL-13-secreting T cells, sensitivity and negative predictive value were 100%.

CONCLUSIONS

Enumeration of casein-specific IL-4- and IL-13-secreting T cells appears a promising tool to improve diagnosis and, if confirmed in larger studies, could permit less frequent use of the oral food challenge.

How to reintroduce cow's milk?

In a child that is allergic to milk, the natural next step, following the elimination diet, is the reintroduction of cow's milk. Several questions may arise. When feasible, this reintroduction has many benefits for the child and his family. However, the disease needs to be well defined by physicians and explained to parents. They need to understand that there are different types of allergy to cow's milk, specifically IgE- and non-IgE-mediated, and each of these may exhibit both a variable duration and frequently an incomplete recovery. Deciding where to first reintroduce cow's milk to a child who has previously followed a milk-free diet, whether it be at home or in a hospital, also frequently presents an issue. Following this first reintroduction, the progressive increase of milk into the diet needs to be managed properly, as not all children will go back to a normal dairy products intake. Recent studies show that most children with milk allergy tolerate products containing baked milk and that their consumption might speed up recovery. Hence, the purpose of the milk challenge in a child on a milk-free diet is becoming, even in a child still reactive to milk, the first step of gradual and individually adapted reintroduction of milk or dairy products. When reintroduction of cow's milk does not work, immunotherapy becomes an option, and this is carried out in specialized centers.

The natural history of IgE-mediated food allergy: can skin prick tests and serum-specific IgE predict the resolution of food allergy?

IgE-mediated food allergy is a transient condition for some children, however there are few indices to predict when and in whom food allergy will resolve. Skin prick test (SPT) and serum-specific IgE levels (sIgE) are usually monitored in the management of food allergy and are used to predict the development of tolerance or persistence of food allergy. The aim of this article is to review the published literature that investigated the predictive value of SPT and sIgE in development of tolerance in children with a previous diagnosis of peanut, egg and milk allergy. A systematic search identified twenty-six studies, of which most reported SPT or sIgE thresholds which predicted persistent or resolved allergy. However, results were inconsistent between studies. Previous research was hampered by several limitations including the absence of gold standard test to diagnose food allergy or tolerance, biased samples in retrospective audits and lack of systematic protocols for triggering re-challenges. There is a need for population-based, prospective studies that use the gold standard oral food challenge (OFC) to diagnose food allergy at baseline and follow-up to develop SPT and sIgE thresholds that predict the course of food allergy.

Cow's milk allergy: from allergens to new forms of diagnosis, therapy and prevention

The first adverse reactions to cow's milk were already described 2,000 years ago. However, it was only 50 years ago that several groups started with the analysis of cow's milk allergens. Meanwhile the spectrum of allergy eliciting proteins within cow's milk is identified and several cow's milk allergens have been characterized regarding their biochemical properties, fold and IgE binding epitopes. The diagnosis of cow's milk allergy is diverse ranging from fast and cheap in vitro assays to elaborate in vivo assays. Considerable effort was spent to improve the diagnosis from an extract-based into a component resolved concept. There is still no suitable therapy available against cow's milk allergy except avoidance. Therefore research needs to focus on the development of suitable and safe immunotherapies that do not elicit severe side effect.