Distinct patterns of cow's milk allergy in infancy defined by prolonged, two-stage double-blind, placebo-controlled food challenges

Home-Based Double-Blind, Placebo-Controlled Challenges for Diagnosis of Delayed Gluten/Milk Hypersensitivity in Children

BACKGROUND

Delayed hypersensitivity to gluten and milk protein is frequently reported but may be difficult to diagnose.

OBJECTIVE

We aimed to explore if a method of home-based double-blind placebo-controlled food challenges (H-FC) can identify and reduce unnecessary elimination diets in children.

METHODS

We included 73 of 92 children aged 1 to 17 years referred to a tertiary allergy clinic from 2011 to 2021 due to self-reported, delayed symptoms to gluten or milk. The children were randomized to H-FC, receiving gluten/milk protein or placebo for 5 to 7 days in a double-blind crossover manner, separated by 3 washout weeks. Patients/parents recorded symptoms using standardized forms. Two crossover periods were used from 2011 to 2016 and 3 periods from 2017 to 2021. A positive challenge required significantly more symptoms during the active period versus the placebo period. After the challenge, reintroduction of milk/gluten was assessed by a follow-up interview. The primary outcome was the proportion of children with a positive challenge.

RESULTS

The children, with a mean age of 11 years, had followed a strict gluten-free or milk-protein-free diet for a median duration of 24 months (range: 3-180 months). A positive challenge was observed in 18 of 73 children (25%), more often using 2 (35%) compared with 3 challenge periods (12%). At follow-up, 44 of 55 (80%) children with a negative challenge had successfully reintroduced milk/gluten.

CONCLUSIONS

H-FC may be an effective method in avoiding unnecessary elimination diets in children. Only 25% of the challenges were positive, and 80% of the children with negative challenges succeeded in reintroducing the food. Three challenge periods may be necessary to reduce false-positive outcomes.

Underlying Immune Mechanisms Involved in Cow’s Milk-Induced Hypersensitivity Reactions Manifesting as Atopic Dermatitis

Of the many symptoms associated with cow’s milk allergy (CMA), many populations face the burden of the appearance or worsening of atopic dermatitis (AD) when consuming milk products. Due to the prevalence and possible severity of symptoms, it is important to understand the underlying immune mechanisms involved in such reactions. Hypersensitivity reactions are exaggerated immune responses to often benign antigens, many times resulting in a cascade of pro-inflammatory processes. Of the four major types, type I and IV are of most relevance when considering atopic dermatitis worsened by cow’s milk. Considered a “true allergy,” type I (immediate) hypersensitivity reactions occur within hours after secondary exposure to an allergen and are primarily driven by antibodies and humoral immune responses. On the contrary, type IV (delayed) hypersensitivity reactions are driven by cell-mediated responses involving T-cell activation. Due to the array of symptoms induced by these complex reactions, it is imperative to diagnose early and treat appropriately. In this literature review, we aim to highlight the primary underlying immune contributors to hypersensitivity reactions, discuss AD as a manifestation of hypersensitivity reactions to cow’s milk, and consider current and future treatment options for combatting hypersensitivities manifesting as AD.

Peanut Can Be Used as a Reference Allergen for Hazard Characterization in Food Allergen Risk Management: A Rapid Evidence Assessment and Meta-Analysis

Regional and national legislation mandates the disclosure of “priority” allergens when present as an ingredient in foods, but this does not extend to the unintended presence of allergens due to shared production facilities. This has resulted in a proliferation of precautionary allergen (“may contain”) labels (PAL) that are frequently ignored by food-allergic consumers. Attempts have been made to improve allergen risk management to better inform the use of PAL, but a lack of consensus has led to variety of regulatory approaches and nonuniformity in the use of PAL by food businesses. One potential solution would be to establish internationally agreed “reference doses,” below which no PAL would be needed. However, if reference doses are to be used to inform the need for PAL, then it is essential to characterize the hazard associated with these low-level exposures. For peanut, there are now published data relating to over 3000 double-blind, placebo-controlled challenges in allergic individuals, but a similar level of evidence is lacking for other priority allergens. We present the results of a rapid evidence assessment and meta-analysis for the risk of anaphylaxis to a low-level allergen exposure for priority allergens. On the basis of this analysis, we propose that peanut can and should be considered an exemplar allergen for the hazard characterization at a low-level allergen exposure.

Anxiety-like behavior and intestinal microbiota changes as strain-and sex-dependent sequelae of mild food allergy in mouse models of cow's milk allergy

A number of studies have reported comorbidity of food allergies with various neuropsychiatric disorders, such as anxiety, depression, attention-deficit hyperactivity disorder, and autism. However, inconsistent results across clinical studies have left the association between food allergy and behavioral disorders inconclusive. We postulated that the heterogeneities in genetic background among allergic cohorts affect symptom presentation and severity of food allergy, introducing bias in patient selection criteria toward individuals with overt physical reactions. To understand the influence of genetic background on food allergy symptoms and behavioral changes beyond anaphylaxis, we generated mouse models with mild cow's milk allergy by sensitizing male and female C57BL/6J and BALB/cJ mice to a bovine whey protein, β-lactoglobulin (BLG; Bos d 5). We compared strain- and sex-dependent differences in their immediate physical reactions to BLG challenge as well as anxiety-like behavior one day after the challenge. While reactions to the allergen challenge were either absent or mild for all groups, a greater number of BLG-sensitized BALB/cJ mice presented visible symptoms and hypothermia compared to C57BL/6J mice. Interestingly, male mice of both strains displayed anxiety-like behavior on an elevated zero maze without exhibiting cognitive impairment with the cross maze test. Further characterization of plasma cytokines/chemokines and fecal microbiota also differentiated strain- and sex-dependent effects of BLG sensitization on immune-mediator levels and bacterial populations, respectively. These results demonstrated that the genetic variables in mouse models of milk allergy influenced immediate physical reactions to the allergen, manifestation of anxiety-like behavior, levels of immune responses, and population shift in gut microbiota. Thus, stratification of allergic cohorts by their symptom presentations and severity may strengthen the link between food allergy and behavioral disorders and identify a population(s) with specific genetic background that have increased susceptibility to allergy-associated behavioral disorders.

Probabilistic risk assessment for milk in dark chocolate, cookies and other baked goods with PAL sold in Canada

The risk of having an allergic reaction in milk-allergic individuals consuming products with precautionary allergen labelling (PAL) for milk has been rarely studied in products such as dark chocolate, cookies, and other baked goods. A probabilistic risk assessment model was developed to estimate potential risks. Milk occurrence and contamination levels were reported in a previous article from our group. Dose-response curves for milk were constructed using values (n = 1078) from published double-blind placebo-controlled food challenges. Canadian consumption data was extracted from a national survey, and a homemade survey involving food-allergic Canadians. Milk eliciting doses (ED) were 0.23 (ED₀₁), 1.34 (ED₀₅), 3.42 (ED₁₀), and 16.3 (ED₂₅) mg of milk protein (Log-Normal distribution). Average exposures, per eating occasion, were 24 mg (dark chocolate), 3.9 mg (baked goods), and 0.20 mg (cookies) of milk proteins. The estimated risk of having a milk-induced allergic reaction by consuming foods with PAL for milk was higher for dark chocolate (16%; 15,881/100,000) than baked goods (3.8%; 3802/100,000) or cookies (0.6%; 646/100,000) in milk-allergic Canadians. Dark chocolate, cookies, and baked goods with PAL for milk, should be avoided by milk-allergic Canadians (consuming or not products with PAL) to prevent allergic reactions.

Pancreatic Enzyme Supplementation in Patients with Atopic Dermatitis and Food Allergies: An Open-Label Pilot Study

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease that affects both patients and their families. Current therapies often alleviate symptoms but do not prevent or eradicate the disease.

OBJECTIVES

Our objective was to determine whether pancreatic enzyme supplementation is an effective and safe treatment in refractory pediatric AD associated with food allergies.

METHODS

We conducted an open-label pilot study using a case-control design. Patients with severe AD and known food allergies refractory to conventional therapies and exclusion diets were recruited and treated for 6 weeks with oral supplementation of pancreatic enzymes. The primary endpoint was the severity of AD, using the Scoring Atopic Dermatitis (SCORAD) index. Secondary measures included markers of intestinal permeability (urinary sucrose and lactulose/mannitol excretion).

RESULTS

A total of 11 patients met all eligibility criteria and completed the trial. Significant improvement in AD was observed after 6 weeks of pancreatic enzyme supplementation (SCORAD index 52.3 ± 5.5 vs. 34.6 ± 7.6; p = 0.0008). Beneficial effect was observed in 9 of 11 patients, without adverse events. Fractional urinary sucrose excretion improved to a level comparable to that of age-matched controls (p < 0.05). However, urinary lactulose:mannitol ratios remained abnormally high compared with those of controls (p = 0.01).

CONCLUSIONS

Pancreatic enzyme supplementation was associated with improved AD and gastroduodenal permeability. Additional randomized placebo-controlled studies are required before this treatment can be recommended in this clinical setting.

Development and Validation of a Lateral Flow Immunoassay Test Kit for Dual Detection of Casein and β-Lactoglobulin Residues

Allergies to cow's milk are very common and can present as life-threatening anaphylaxis. Consequently, food labeling legislation mandates that foods containing milk residues, including casein and/or β-lactoglobulin, provide an indication of such on the product label. Because contamination with either component independent of the other can occur during food manufacturing, effective allergen management measures for containment of milk residues necessitates the use of dual screening methods. To assist the food industry in improving food safety practices, we have developed a rapid lateral flow immunoassay test kit that reliably reports both residues down to 0.01 μg per swab and 0.1 ppm of protein for foods. The assay utilizes both sandwich and competitive format test lines and is specific for bovine milk residues. Selectivity testing using a panel of matrices with potentially interfering substances, including commonly used sanitizing agents, indicated reduction in the limit of detection by one-to fourfold. With food, residues were easily detected in all cow's milk-based foods tested, but goat and sheep milk residues were not detected. Specificity analysis revealed no cross-reactivity with common commodities, with the exception of kidney beans when present at high concentrations (> 1%). The development of a highly sensitive and rapid test method capable of detecting trace amounts of casein and/or β-lactoglobulin should aid food manufacturers and regulatory agencies in monitoring for milk allergens in environmental and food samples.

Clinical and follow up assessment of children in a program directed at the use of formulas for cow's milk protein allergy

OBJECTIVE

To determine clinical and follow up characteristics of children enrolled in a program to supply formulas for cow's milk allergy.

METHODS

descriptive study of a convenience sample composed of 214 children up to three years old, with clinical diagnosis of cow's milk allergy and/or standardized oral challenge, referred to the Program of Formulas for Cow's Milk Allergy at a Pediatric University Hospital, in Natal, Rio Grande do Norte, Brazil (2007/2009). Clinical-epidemiological data and formula indication (soy, protein hydrolysates or aminoacid formula) were assessed at the first consultation. Clinical response and nutritional evolution (Anthro-OMS2006) were observed after three months. Chi-square and paired t-test were used, being p<0.05 significant.

RESULTS

At the first consultation, mean age was 9.0±6.9 months. Digestive manifestations occurred in 81.8%; cutaneous ones, in 36.9% and respiratory ones in 23.8%. BMI Z-score <-2.0 standard deviations (SD) was found in 17.9% of children with isolated digestive symptoms, in 41.7% of those using cow's milk and in 8.7% of those using other formulas (p<0.01). The following formulas were used: soy in 61.2%, protein hydrolysates in 35.4% and aminoacids in 3.3%. Mean BMI Z-scores at initial consultation and after three months were, respectively: -0.24±1.47SD and 0.00±1.26SD (p=0.251), with soy formula, and -0.70±1.51SD and -0.14±1.36SD (p=0.322) with protein hydrolysates formula.

CONCLUSIONS

Digestive manifestations of cow's milk allergy were preponderant, and lead to greater nutritional impairment. The use of replacement formulas (isolated soy protein and protein hydrolysates) was important to maintain the nutritional status.

Double-blind placebo-controlled food challenges in children with alleged cow's milk allergy: prevention of unnecessary elimination diets and determination of eliciting doses

Background

Children with cow’s milk allergy (CMA) need a cow’s milk protein (CMP) free diet to prevent allergic reactions. For this, reliable allergy-information on the label of food products is essential to avoid products containing the allergen. On the other hand, both overzealous labeling and misdiagnosis that result in unnecessary elimination diets, can lead to potentially hazardous health situations. Our objective was to evaluate if excluding CMA by double-blind placebo-controlled food challenge (DBPCFC) prevents unnecessary elimination diets in the long term. Secondly, to determine the minimum eliciting dose (MED) for an acute allergic reaction to CMP in DBPCFC positive children.

Methods

All children with suspected CMA under our care (Oct’05 - Jun’09) were prospectively enrolled in a DBPCFC. Placebo and verum feedings were administered on two randomly assigned separate days. The MED was determined by noting the ‘lowest observed adverse effect level’ (LOAEL) in DBPCFC-positive children. Based on the outcomes of the DBPCFC a dietary advice was given. Parents were contacted by phone several months later about the diet of their child.

Results

116 children were available for analysis. In 76 children CMA was rejected. In 60 of them CMP was successfully reintroduced, in 2 the parents refused introduction, in another 3 the parents stopped reintroduction. In 9 children CMA symptoms reappeared. In 40 children CMA was confirmed. Infants aged ≤ 12 months in our study group have a higher cumulative distribution of MED than older children.

Conclusions

Excluding CMA by DBPCFC successfully stopped unnecessary elimination diets in the long term in most children. The MEDs form potential useful information for offering dietary advice to patients and their caretakers.

Comparison of open and double-blind placebo-controlled food challenges in diagnosis of food hypersensitivity amongst children

BACKGROUND

Correct diagnosis of food hypersensitivity (FHS) is important to ensure appropriate patient care and to accurately establish the population prevalence and incidence. Food challenges play a very important role in the diagnosis of FHS, but it is unclear when open food challenges (OFCs) opposed to double-blind placebo-controlled food challenges (DBPCFCs) should be used. This study investigated the use of OFCs and DBPCFCs when diagnosing FHS.

METHODS

Children with a reported history of FHS or with sensitization to a food without known previous consumption were invited to undergo food challenges. Children of consenting parents underwent an OFC and those with a positive OFC were approached to undergo a DBPCFC. Food challenges were either performed as 1-day or 1-week challenges depending on sensitization status and clinical history.

RESULTS

Forty-one children underwent both OFCs and DBPCFCs. The positive predictive values for 1-day and 1-week OFCs were 73% (8/11; 95% CI: 39-94%) and 57% (20/35; 95% CI: 39-74%) respectively. There was no evidence to indicate that the younger children were more likely to have a positive OFC confirmed by a DBPCFC compared to older children (Fisher's exact P = 0.53). In the 1-day challenges parents indicated a preference for OFC rather than DBPCFC. By contrast, in the 1-week challenge parents indicated a preference for DBPCFC (P = 0.0192).

CONCLUSION

Open food challenge may be suitable for diagnosing immediate objective symptoms, whereas DBPCFC may be needed for the diagnosis of delayed and mainly subjective symptoms, irrespective of the child's age.

Placebo reactions in double-blind, placebo-controlled food challenges in children

BACKGROUND

A cardinal feature of the double-blind, placebo-controlled food challenge (DBPCFC) is that placebo administration is included as a control. To date, the occurrence and diagnostic significance of placebo events have not extensively been documented.

OBJECTIVE

To analyse the occurrence and features of placebo events in DBPCFCs and to assess their contribution to the diagnostic accuracy of the DBPCFC in children.

METHODS

The study population consisted of 132 challenges in 105 sensitized children (age range 0.7-16.6 years, median 5.3 years), who underwent DBPCFCs with cow's milk, egg, peanut, hazelnut and soy. Placebo and active food challenges were performed on different days.

RESULTS

A total number of 17 (12.9%) positive placebo events occurred, which could be classified as immediate (9/17), late-onset (8/17), objective (11/17) or subjective (6/17). Four of 74 (5.4%) positive active food challenges were revealed to be false positive by administration of a placebo challenge. This is 3% (4/132) of all challenges. When computed by a statistical model, the false positive rate was 0.129 (12.9% of all challenges).

CONCLUSION

Placebo events with diverse clinical characteristics occur in DBPCFCs in a significant number of children. The diagnostic significance of the administration of a placebo challenge is first, to identify false positive diagnoses in DBPCFCs by refuting false positive tests in individual patients. Secondly, to allow for blinding of the active food challenge. Thirdly, applying a statistical model demonstrates that some positive challenges may be false positive and that the test may need to be repeated in selected cases.

Prevalence of sensitization to food allergens, reported adverse reaction to foods, food avoidance, and food hypersensitivity among teenagers

BACKGROUND

There is a paucity of information on food hypersensitivity (FHS) among teenagers.

OBJECTIVES

We sought to investigate the sensitization rates, perception of FHS, food avoidance, and FHS assessed by means of food challenges among teenagers.

METHODS

This cohort study recruited 757 eleven-year-olds and 775 fifteen-year-olds in the United Kingdom. Sensitization rates, reported rates of FHS, and rates of food avoidance were measured. The prevalence of FHS was established by using food challenges.

RESULTS

The prevalence of reported FHS among the 11- and 15-year-old cohorts was 11.6% (90/775) and 12.4% (94/757), respectively. One hundred twenty-two (15.7%) and 142 (18.7%) of the 11- and 15-year-olds reported they were avoiding some food. The rates of sensitization to the food allergens were 5.1% (36/699) and 4.9% (32/649) for the 11- and 15-year-olds, respectively. FHS was confirmed in 8 (1.0%) 11-year-old children and 8 (1.0%) 15-year-old children by means of open food challenge and in 1 (0.1%) 11-year-old and 4 (0.5%) 15-year-olds by means of double-blind, placebo-controlled food challenge. The prevalence of FHS, as confirmed by using open food challenges and positive skin prick test responses plus a history of adverse reactions, was 18 (2.3%) of 775 in the 11-year-old cohort and 17 (2.3%) of 757 in the 15-year-old cohort.

CONCLUSIONS

The rate of reported FHS was significantly more than sensitization to the predetermined allergens (odds ratio, 2.17; 95% CI, 1.47-3.18; P < .001 in the 11-year-olds; odds ratio, 2.73; 95% CI, 1.81-4.13; P < .001 in the 15-year-olds). By means of objective assessment, 2.3% of both 11- and 15-year-old children had FHS, with the majority showing immediate reactions.

Evaluation of the utility of atopy patch testing, skin prick testing, and total and specific IgE assays in the diagnosis of cow's milk allergy

BACKGROUND

Information on the utility of atopy patch testing (APT) in the diagnosis of food allergy is derived from studies of children with atopic dermatitis.

OBJECTIVE

To evaluate the usefulness of APT in the diagnosis of cow's milk allergy (CMA) and to determine interleukin 4 and interferon-gamma production by peripheral blood mononuclear cells.

METHODS

Thirty-seven children (median age, 11 months) with suspected CMA who had a variety of symptoms that involved many organ systems were evaluated using double-blind placebo-controlled food challenges (DBPCFCs), and the performances of milk specific IgE, skin prick testing (SPT), and APT were determined. To search for a possible relationship between the diagnostic tests and the TH1/TH2 immune response, we measured interferon-gamma and interleukin 4 levels in the supernatants of peripheral blood mononuclear cell cultures.

RESULTS

Seventeen children with positive DBPCFC results and 6 with a history of anaphylaxis were diagnosed as having CMA. The combined use of APT and SPT had a sensitivity of 100% and a negative predictive value of 100% but a specificity of 50% and a positive predictive value of 76%. The addition of milk specific IgE assays to APT and SPT did not improve these values. Pattern of cytokine secretion was not associated with APT positivity or a specific response to DBPCFC.

CONCLUSIONS

Atopy patch testing may be a useful adjunct to SPT in excluding CMA in children who have allergic manifestations other than atopic dermatitis. However, DBPCFCs are still necessary in the presence of positive test results.

Therapeutic modalities for cow's milk allergy

OBJECTIVE

To discuss current therapeutic modalities for cow's milk allergy and its prevention.

DATA SOURCES AND STUDY SELECTION

The sources of data include original clinical studies carried out at Ste. Justine Hospital, as well as a systematic search of the published English and French language scientific literature restricted to human subjects using computerized searches (National Public Library of Medicine, Cochrane Database Systems Review) from 1997 to 2002. Search terms for article retrieval included food allergy, milk allergy, therapy, and prevention.

CONCLUSIONS

The therapy of food allergies depends upon an accurate diagnosis, which remains a challenge in non--IgE-mediated cases. Dietary exclusion remains the mainstay of therapy, with medications reserved for exceptional patients. Preliminary evidence suggests that pancreatic enzyme supplementation may be of benefit for cases with multiple food allergies and severe eczema. Hydrolysate formula use is currently recommended for dietary allergy prevention in infants at an increased risk when maternal milk is insufficient or unavailable. The use of partially hydrolyzed formulas to prevent allergic disorders, including atopic dermatitis, is supported by clinical studies, but cannot be used in the already sensitized, milk-allergic child. Probiotics show enormous potential in preventing food allergic disorders as well.

Diagnostic accuracy of fecal calprotectin assay in distinguishing organic causes of chronic diarrhea from irritable bowel syndrome: a prospective study in adults and children

BACKGROUND

Fecal calprotectin (FC) has been proposed as a marker of inflammatory bowel disease (IBD), but few studies have evaluated its usefulness in patients with chronic diarrhea of various causes. We evaluated the diagnostic accuracy of a FC assay in identifying "organic" causes of chronic diarrhea in consecutive adults and children.

METHODS

We consecutively enrolled 70 adult patients (30 males, 40 females; median age, 35 years) and 50 children (20 males, 30 females; median age, 3.5 years) with chronic diarrhea of unknown origin. All patients underwent a complete work-up to identify the causes of chronic diarrhea. FC was measured by ELISA.

RESULTS

In adult patients, FC showed 64% sensitivity and 80% specificity with 70% positive and 74% negative predictive values for organic causes. False-positive results (8 of 40 cases) were associated with the use of aspirin (3 cases) or nonsteroidal antiinflammatory drugs (1 case) and with the presence of concomitant liver cirrhosis (3 cases). False-negative results mainly included patients suffering from celiac disease (5 cases). Patients with IBD (9 cases) were identified with 100% sensitivity and 95% specificity. In pediatric patients, sensitivity was 70%, specificity was 93%, and positive and negative predictive values were 96% and 56%. False-negative results (11 of 35 cases) were associated mainly with celiac disease (6 cases) or intestinal giardiasis (2 cases).

CONCLUSIONS

FC assay is an accurate marker of IBD in both children and adult patients. In adults, false negatives occur (e.g., in celiac disease) and false-positive results are seen in cirrhosis or users of nonsteroidal antiinflammatory drugs. Diagnostic accuracy is higher in children.

Markers of inflammation in the feces of infants with cow's milk allergy

Growing evidence exists that exposure to cow's milk elicits inflammation in the gut of infants with cow's milk allergy, irrespective of symptoms. To demonstrate inflammation and increased protein leakage from the gut during a cow's milk elimination-challenge test in fecal samples of infants presenting with different symptoms suggestive of cow's milk allergy, we measured the concentrations of alpha1-antitrypsin (AT), eosinophil cationic protein (ECP), immunoglobulin (Ig) A, and cow's milk-specific IgA antibodies, in fecal samples of 208 infants with a mean age of 7 months. Prechallenge samples were collected after a mean 3-week elimination period, and post-challenge samples were obtained 4 days after starting the challenge. Fecal levels of prechallenge total IgA (p = 0.02) and post-challenge AT (p = 0.001) were higher in infants with a positive challenge. Of these infants, pre- and post-challenge levels of ECP were higher in those reacting after 24 h than in those reacting within 1 h (p = 0.006 and p = 0.045). Prechallenge levels of ECP were higher in those showing intestinal symptoms (p = 0.008), and both pre- and post-challenge levels of total IgA were higher in those with an IgE-mediated reaction to cow's milk (p = 0.04 and p = 0.008). Regardless of the challenge result, total IgA increased during the challenge (p < 0.001 for both challenge-positive and -negative infants) and was higher in those breast-fed until the challenge than in those fed formula only (p < 0.01). Hence, in infants reacting to the cow's milk challenge, higher prechallenge levels of fecal IgA indicate increased antigenic stimuli in the gut, and higher post-challenge levels of AT reflect increased protein loss as a result of intestinal inflammation. In infants with slowly evolving gastrointestinal symptoms, increased fecal ECP may help in distinguishing patients from those who tolerate cow's milk. Individual serial follow-up of fecal IgA and ECP can be used to estimate the degree of inflammation in the gut and an appropriate time for a challenge test, but are not diagnostic tools for cow's milk allergy.

Allergic gastroenteropathy in preterm infants

OBJECTIVES

To determine the clinical presentation, histopathologic features, and outcome of biopsy-proven allergic gastroenteropathy (AGE) in preterm infants. We hypothesized that AGE is a more frequent cause of gastrointestinal disease in this population than previously suspected.

STUDY DESIGN

The retrospective portion of the study, from 1992 to 1997, included preterm infants <37 weeks' gestation who underwent biopsy because of suspected AGE. The prospective portion, from January to December 1998, included 20 infants undergoing endoscopy and biopsy because of suspected AGE.

RESULTS

Twenty-five infants (12 retrospective/13 prospective) with mean gestational age of 29 weeks at birth and mean postnatal age at diagnosis of 78 days were diagnosed with AGE. Three clinical patterns of presentation were noted: group 1, gastroesophageal reflux disease (n = 5); group 2, non-specific feeding intolerance (n = 8); and group 3, lower gastrointestinal bleeding (n = 12). Ten patients had negative biopsy findings (3 retrospective/7 prospective) and had clinical features indistinguishable from those of groups 1 and 2. Patients in group 3 were most likely to have positive biopsy findings (12 of 12). Fifteen patients responded to a casein hydrolysate formula, and 10 patients required an amino acid-based formula. Patients with AGE who had eosinophilic infiltration and villous atrophy took longer to recover than those with eosinophilic infiltration alone (P <.03). Subsequently, most have tolerated formula challenges and are currently tolerating cow's milk.

CONCLUSIONS

AGE may be an under-recognized cause of gastrointestinal symptoms in preterm infants. Confirmation with endoscopy and biopsy can be done safely and provides the basis for appropriate dietary management.

Infant feeding patterns affect the subsequent immunological features in cow's milk allergy

BACKGROUND

The first exposure to food antigens provokes an immune reaction in an infant, its type depending on the quantity and frequency of doses and the age at introduction, and also being influenced by genetic factors. Most infants develop tolerance to food antigens, but in a small minority they provoke adverse symptoms.

OBJECTIVE

To study the effects of breast and formula feeding and other environmental and genetic factors on the subsequent type of cow's milk allergy classified by the presence or absence of immunoglobulin (Ig) E antibodies to cow's milk.

METHODS

A cohort of 6209 infants was followed prospectively from birth for symptoms of cow's milk allergy. The infant-feeding regimen was recorded at the maternity hospital and at home. At a mean age of 6.7 months, a total of 118 infants (1.9%) reacted adversely to a challenge with cow's milk. Before the challenge, the response to a skin-prick test with cow's milk and serum IgE cow's milk antibodies was measured.

RESULTS

At challenge, 75 (64%) infants showed IgE-positive reactions to cow's milk, their most common symptom being acute-onset urticaria. Significant risk factors for the presence of IgE cow's milk antibodies in allergic infants were long breast-feeding (odds ratio [OR] 3.9, 95% confidence interval [CI] 1.6-9.8), exposure to cow's milk at the maternity hospital (OR 3.5, 95% CI 1.2-10.1) and breast-feeding during the first 2 months at home either exclusively (OR 5.1, 95% CI 1.6-16.4) or combined with infrequent exposure to small amounts of cow's milk (OR 5.7, 95% CI 1.5-21.6). Fifty infants had their first adverse symptoms during exclusive breast-feeding, and 32 infants were sensitized during exclusive breast-feeding. Most of the infants in both cases were IgE-positive: 37 and 23, respectively.

CONCLUSIONS

In infants who are prone to developing cow's milk allergy, prolonged breast-feeding exclusively or combined with infrequent exposure to small amounts of cow's milk during the first 2 months of life induces development of IgE-mediated response to cow's milk.

Food-induced malabsorption syndromes

A syndrome of chronic diarrhea, vomiting, and failure to thrive was described 35 years ago. The syndrome was caused by damage in the jejunum after ingestion of cow's milk. Symptoms appeared in young infants shortly after introduction of cow's milk formula. Patients had moderate steatorrhea, decreased absorption of D-xylose, and, often, iron-deficiency anemia and hypoproteinemia. They had strong IgA and IgG antibodies to cow's milk. IgE antibodies to cow's milk were negative, as a rule. Indicators of cell-mediated immune reaction to cow's milk proteins were often positive. Patients were tolerant to cow's milk by the age of 3 years. Malabsorption was due to damage to the jejunal mucosa: Varying villus atrophy was associated with inflammation in surface epithelium and lamina propria. The epithelial cell renewal rate increased. Surface epithelial cells decreased in height, with short, furry microvilli and large aggregates of lysozymes. The number of intraepithelial lymphocytes was markedly increased, but normalized during cow's milk elimination. Most of these lymphocytes had alpha/beta T-cell receptors, and many were cytotoxic. Some specimens had an increase in gamma/delta T-cell receptor-bearing cells. In the lamina propria, CD4+ cells predominated, and some of them were activated. IgA- and IgM-containing cells were markedly increased during cow's milk exposure, but IgE cells were not abnormal. The density of eosinophils was moderately increased. Secretion of interferon-gamma by cells isolated from patients' intestines was markedly increased. Morphologic and immunologic findings suggest that T-cell-mediated reaction to proteins in cow's milk is present in the small intestines of patients with this syndrome and causes this enteropathy.

Electrochemical detection of allergen in small-volume whole blood using an array microelectrode: a simple method for detection of allergic reaction

A safe, simplified, and rapid method for detection of allergen has been developed. Serotonin, a chemical mediator secreted during an allergic reaction, was used as a marker in electrochemical detection. A 20-microL drop of whole blood was used for the electrochemical detection of allergen using an array microelectrode. When cyclic voltammetry was carried out on whole blood samples containing 1 microg/mL serotonin, an anodic peak current appeared at around 350 mV versus a silver/silver chloride electrode using a Nafion-coated array microelectrode. Allergen was selectively detected using whole blood samples by applying a constant potential of 350 mV after 40 min incubation with addition of allergen. The results obtained by the electrochemical detection method correlated well with the diagnosis obtained from the amount of IgE antibody.

The time-course of milk antigen-induced TNF-alpha secretion differs according to the clinical symptoms in children with cow's milk allergy

BACKGROUND

TNF-alpha secretion by blood mononuclear cells stimulated with cow's milk proteins is significantly higher in infants with active cow's milk allergy (CMA) manifested by digestive symptoms than in children who have recovered from CMA.

OBJECTIVE

The current study was undertaken to analyze the kinetics of TNF-alpha secretion and to evaluate the usefulness of the measurement of TNF-alpha release in whole blood cultures in the prediction of clinical outcome after milk challenge.

METHODS

Blood samples were obtained from 83 children maintained on a cow's milk-free diet and examined just before a cow's milk provocation. Children were divided into 4 groups according to clinical outcome: group I (active CMA with cutaneous symptoms), group II (active CMA with predominantly digestive symptoms), group III (children recovered from CMA), and group IV (control). The kinetics of TNF-alpha secretion was measured in blood cultured for 1 to 5 days at different cow's milk protein concentrations.

RESULTS

On day 1 TNF-alpha secretion was significantly higher in group I (485 [453] pg/mL, mean [SD], P <.005) and in group II (269 [102] pg/mL, P <. 005) than that observed in groups III and IV (149 [95] and 87 [71] pg/mL, respectively). Then TNF-alpha was rapidly degraded and a second peak of secretion was observed on day 5 but only in group II (278 [221] pg/mL), whereas in groups I, III, and IV a low secretion was observed (70 [61], 45 [40], and 11 [12] pg/mL, respectively, P <. 02).

CONCLUSION

These results show that the pattern of TNF-alpha secretion in response to cow's milk proteins is different in CMA infants with cutaneous or digestive symptoms and suggest that TNF-alpha release might predict clinical relapse on challenge.

Outcome of double-blind, placebo-controlled food challenge tests in 107 children with atopic dermatitis

BACKGROUND AND OBJECTIVE

Little is known about late phase clinical reactions during oral food challenges and the value of specific IgE in terms of sensitivity and specificity.

METHODS

We therefore analysed retrospectively the clinical outcome of 387 oral provocations during double-blind, placebo-controlled food challenge tests in 107 children with atopic dermatitis.

RESULTS

Eighty-seven (81%) children showed a positive clinical reaction to at least one challenge. The vast majority of children (94%) showed clinical symptoms to one or two allergens. One hundred and thirty-one of 259 (51%) of verum challenges and 1/128 (0.8%) placebo challenge were assessed as positive. Oral provocations with hen's egg showed the highest percentage of positive reactions (70%). Sensitivity of specific IgE to the four allergens tested was 90%, specificity 30%. Sensitivity of the parental history as a predictive factor was 48%, specificity 72%. Ninety-two of 131 (70%) children with positive verum provocations showed early reactions, 33 (25%) late and six (5%) combined early and late reactions. In 84/131 (64%) positive provocations one organ system was involved, while in 44 (34%) provocations two and in three (2%) challenges three organ systems were involved. Skin reactions were the most frequent clinical manifestation leading to positive reactions followed by gastro-intestinal and respiratory symptoms. There was no correlation between titration dose and specific IgE. The subgroup of non-sensitized children did not differ in terms of sex, age or titration dose from the total study population.

CONCLUSION

Double-blind, placebo-controlled oral food challenges are helpful in distinguishing children with clinically manifested symptoms from those with food sensitization. Accurately identifying children with a clinical relevant food allergy may help to prescribe specific diets on a scientific basis, avoiding dietary limitations which may be unnecessary or even harmful.

Clinical food hypersensitivity: the relevance of duodenal immunoglobulin E-positive cells

Owing to poor reliability of laboratory tests, diagnosis of food allergy is based on clinical response to double-blind placebo-controlled food challenge. The aim of the present study was to assess the value of duodenal IgE-positive cells in the diagnosis of food allergy. Thirty-one children with a history of possible food allergy underwent duodenal biopsies, skin prick tests, and measurement of serum IgE antibodies, and were put on an elimination diet followed by food challenge. Open food challenges were performed in patients under 12 mo of age, and double-blind placebo-controlled challenges were for suspected foods. On the basis of clinical food hypersensitivity, patients were divided into two groups. Group 1 consisted of 13 children with food allergy. Thirteen of 20 positive provocations elicited reactions within 12 h from the end of the challenge, seven later. Group 2 was the control group and included 18 patients with negative food challenges. The number of IgE-positive cells in biopsy specimens was significantly more elevated in group 1 with respect to group 2 (153.24 +/- 83.13 versus 18.4 +/- 18.9; p < 0.01). Total serum IgE levels were elevated compared with that of the control group (p < 0.01) and correlated with the number of IgE-positive cells (p < 0.001, r = 0.62). Enhanced IgE-containing cells were found in all delayed reactors, but about one-third had negative skin prick tests or specific serum IgE antibodies to the offending foods. Our results showed that systemic reactions to foods are associated with an IgE-mediated response in the duodenal mucosa. Larger studies would be required to assess the predictive value of an increased number of IgE-positive cells in the diagnosis of allergy to food, especially in children with delayed reactions.

Dientamoeba fragilis masquerading as allergic colitis

BACKGROUND

Dientamoeba fragilis is a rare cause of chronic infectious diarrhea and colitis in children.

METHODS

Review of the clinical manifestations, diagnostic methods, and clinical course of D. fragilis infection in our hospital.

RESULTS

Eleven pediatric patients are discussed, seven of whom had a history of recent travel. Clinical manifestations of infectious diarrhea included anorexia, intermittent vomiting, abdominal pain, and diarrhea, ranging from 1 to 100 weeks in duration. Peripheral eosinophilia was present in seven patients. One patient with well-documented bovine protein allergy had intermittent episodes of diarrhea and abdominal pain, despite an appropriate elimination diet. Eosinophilic colitis documented by colonoscopy, was due to D. fragilis. Metronidazole was effective in treating five patients, and iodoquinol was effective in treating four others.

CONCLUSIONS

D. fragilis should be included in the differential diagnosis of chronic diarrhea and eosinophilic colitis. The identification of this pathogen requires clinical awareness of epidemiologic risk factors and presenting complaints, as well as the laboratory staining procedures essential to its proper identification.