Detection of Salivary Tryptase Levels in Children following Oral Food Challenges.

BACKGROUND: Oral food challenge (OFC) is commonly used to diagnose food allergy. This test is time and resource intensive, and conclusions are not always unequivocal as this relies on the interpretation of symptoms. Therefore, an objective marker would improve the accuracy of the diagnostic workup of food allergy. OBJECTIVES: The aim of this study was to investigate whether tryptase can be detected in saliva of children following OFC. METHOD: Children from 3 to 18 years of age were eligible for inclusion if an OFC for peanut or tree nut had been recommended. Saliva samples were collected prior to the first dose and 5, 10, and 15 min following the last administered dose during OFC. Assay precision, spike-and-recovery, and assessment of lower limit of detection of the tryptase immunoassay were examined before analysis of tryptase in saliva was performed. RESULTS: A total of 30 children were included (median age 8 years, 63.3% male, 53.3% positive OFC outcome). Tryptase was detected in saliva samples. The mean of the change in baseline tryptase value to each saliva collecting time point was significantly different in patients with a positive OFC outcome compared to a negative outcome (p < 0.01). CONCLUSIONS: This study showed that tryptase can be detected in saliva of children following OFC. Increased levels of tryptase compared to baseline were found if the OFC outcome was positive, suggesting that measuring tryptase in saliva may be useful in the diagnosis of food allergy. Further research is needed to evaluate the potential association between tryptase levels and symptoms.

The dilemma of open or double-blind food challenges in diagnosing food allergy in children: Design of the ALDORADO trial.

BACKGROUND: It is of major importance to diagnose food allergy accurately. Current guidelines support the use of oral food challenges to do so. The double-blind placebo-controlled food challenge (DBPCFC) has been regarded as the 'gold standard' for decades. However, DBPCFCs are costly, and time- and resource-intensive procedures. Structural implementation of less demanding open food challenges will only find support if research demonstrates that their outcome is comparable to DBPCFC, yet this has been proven difficult to investigate. METHODS: We performed a literature review to investigate the diagnostic accuracy of oral food challenges and interviewed 19 parents of children with proven or suspected food allergy about the design of a trial to study this. RESULTS: An overview of the dilemma of diagnosing food allergy using oral food challenges, and the methodological issues and parents' opinions to study this. No comparative studies have been performed using the latest guidelines on oral food challenges. CONCLUSIONS: There is an urgent need to investigate the diagnostic accuracy of different oral food challenge protocols. We present the rationale and design of the ALDORADO trial (ALlergy Diagnosed by Open oR DOuble-blind food challenge) that has been set up to investigate whether the outcome of the open food challenge is comparable to DBPCFC.

Health-related quality of life in food-allergic adults from eight European countries.

BACKGROUND: Food allergy can impair health-related quality of life (HRQL). Food Allergy Quality of Life Questionnaires (FAQLQs) have been developed and validated, including an adult form (FAQLQ-AF). HRQL has not, to date, been measured across different European countries using a uniform methodology. OBJECTIVE: To translate and validate the FAQLQ-AF for use in 8 European countries (Iceland, The Netherlands, Poland, France, Spain, Italy, Greece, and Sweden). METHODS: The English FAQLQ-AF was translated, back-translated, and compared for use in the 8 relevant European languages. Adults with a perceived food allergy were recruited from outpatient departments and through a community survey. Participants completed the FAQLQ-AF, the Food Allergy Independent Measure, and questions concerning participants' characteristics. Validity of the FAQLQ-AF was analyzed for use in the 8 countries. RESULTS: The FAQLQ-AF had strong construct validity (r > 0.59) and an excellent internal consistency (Cronbach α > 0.95) in all countries. Total FAQLQ-AF scores (range 3.2-5.0) were significantly different across participating countries. CONCLUSION: The FAQLQ-AF is a suitable and valid instrument for measuring HRQL in food-allergic adults in Iceland, The Netherlands, Poland, France, Spain, Italy, Greece, and Sweden. The impact of food allergy on HRQL seems to differ among adults from the 8 participating European countries.

Eliciting and stop dose during oral food challenges for peanut and common tree nuts in different age groups.

BACKGROUND: Oral food challenges (OFCs) are used to confirm or reject a diagnosis of food allergy. However, younger children may encounter difficulties in consuming all offered doses during an OFC in the absence of symptoms, resulting in inconclusive outcomes. Our aim is to assess the eliciting dose for objective symptoms among various age groups and determine the necessity of consuming the final dose step during an uneventful OFC to avoid false negative outcomes. METHODS: OFCs for common food allergens performed between 2012 and 2019 were analyzed retrospectively. The primary outcome was the association of age with stop dose for OFCs with inconclusive outcome. Secondary outcome measures were the association of age with eliciting dose and the potential number of false negative outcomes. RESULTS: A total of 1327 OFCs were performed in 707 patients. Of these, 514 (38.7%) were positive, 589 (44.4%) negative, and 224 (16.9%) inconclusive. In OFCs with inconclusive outcome, age appeared to be a significant predictor of the stop dose only for almond (p = .005). Objective symptoms occurred after the last dose step in 2%-13% of all OFCs with positive outcome. In our cohort, potential false negative outcomes may have been drawn in 27.6% of uneventful OFCs. CONCLUSIONS: Two third of children under 6 years of age successfully consumed all the provided doses during OFCs with a negative outcome. The eliciting dose for objective symptoms was not associated with age, and in a substantial number of OFCs with positive outcome, symptoms occurred after eating the final dose. These findings suggest that in case of an uneventful OFC, the outcome should be drawn only after a cumulative dose of 4.4 g has been consumed to avoid the risk of a potential false negative outcome.

Food allergy knowledge of parents - is ignorance bliss?

BACKGROUND: Food allergic children are at least partially dependent on their parents to care for their food allergy. In addition, parents are often responsible for the education of others regarding food allergy, including the family, school, neighbors, and friends. The aim of this study was to investigate food allergy knowledge, attitudes, and beliefs of parents with food allergic children in the Netherlands. In addition, a cross-cultural comparison was made between parents from the USA and parents from the Netherlands. METHODS: The original Chicago Food Allergy Research Survey for Parents of Children with Food Allergy (CFARS-PRNT) was translated into Dutch. Parents of children with at least one doctor-diagnosed food allergy were included. Knowledge scores and attitude/beliefs scores were determined and compared with the data from 2945 parents from the USA. Predictors of overall knowledge scores were investigated. RESULTS: Dutch parents of children completed the translated CFARS-PRNT (n = 299). The mean overall knowledge score in the Netherlands was 9.9 after adjusting for guessing, compared with 12.7 in the USA (p < 0.001). Attitudes and beliefs regarding food allergy among parents from the Netherlands were generally more optimistic. The overall knowledge scores could be predicted by country of origin, educational degree, being member of a patient organization, visiting an allergist, and a history of anaphylaxis. CONCLUSIONS: Food allergy knowledge among parents of food allergic children from the Netherlands is suboptimal when compared with their counterparts from the USA, although these parents tend to be more optimistic toward food allergy than parents from the USA.

[Haemorrhagic shock after frenotomy of the lingual and maxillary labial frenula in a neonate]. / Hemorragische shock na frenulotomie bij een neonaat.

Frenotomy of the lingual and maxillary labial frenula in neonates is considered a safe procedure and is increasingly performed globally. However, there is no consistent evidence for the indication and effectiveness of this intervention. In this clinical lesson, we show that frenotomy of the lingual and maxillary labial frenula in neonates is controversial and can have serious complications. We describe a patient that, in addition to pain and the risk of infection, was in a life-threatening haemorrhagic shock after frenotomy of the lingual and maxillary labial frenula. Frenotomy should only be considered after a multi-disciplinary approach of neonates with breastfeeding problems in whom a medical cause is excluded and no contraindications have been identified.

Surface protein profiling of milk and serum extracellular vesicles unveils body fluid-specific signatures.

Cell-derived extracellular vesicles (EVs) are currently in the limelight as potential disease biomarkers. The promise of EV-based liquid biopsy resides in the identification of specific disease-associated EV signatures. Knowing the reference EV profile of a body fluid can facilitate the identification of such disease-associated EV-biomarkers. With this aim, we purified EVs from paired human milk and serum samples and used the MACSPlex bead-based flow-cytometry assay to capture EVs on bead-bound antibodies specific for a certain surface protein, followed by EV detection by the tetraspanins CD9, CD63, and CD81. Using this approach we identified body fluid-specific EV signatures, e.g. breast epithelial cell signatures in milk EVs and platelet signatures in serum EVs, as well as body fluid-specific markers associated to immune cells and stem cells. Interestingly, comparison of pan-tetraspanin detection (simultaneous CD9, CD63 and CD81 detection) and single tetraspanin detection (detection by CD9, CD63 or CD81) also unveiled body fluid-specific tetraspanin distributions on EVs. Moreover, certain EV surface proteins were associated with a specific tetraspanin distribution, which could be indicative of the biogenesis route of this EV subset. Altogether, the identified body fluid-specific EV profiles can contribute to study EV profile deviations in these fluids during disease processes.

Introduction of Heated Cow's Milk Protein in Challenge-Proven Cow's Milk Allergic Children: The iAGE Study.

The introduction of baked milk products in cow's milk (CM) allergic children has previously been shown to accelerate induction tolerance in a selected group of children. However, there is no standardized baked milk product on the market. Recently, a new standardized, heated and glycated cow's milk protein (HP) product was developed. The aim of this study was to measure safety and tolerability of a new, well characterized heated CM protein (HP) product in cow's milk allergic (CMA) children between the age of 3 and 36 months. The children were recruited from seven clinics throughout The Netherlands. The HP product was introduced in six incremental doses under clinical supervision. Symptoms were registered after introduction of the HP product. Several questionnaires were filled out by parents of the children. Skin prick tests were performed with CM and HP product, sIgE to CM and α-lactalbumin (Bos d4), ß-lactoglobulin (Bos d5), serum albumin (Bos d 6), lactoferrin (Bos d7) and casein (Bos d8). Whereas 72% percent (18 out of 25) of the children tolerated the HP product, seven children experienced adverse events. Risk factors for intolerance to the HP product were higher skin prick test (SPT) histamine equivalent index (HEP) results with CM and the HP product, higher specific IgE levels against Bos d4 and Bos d8 levels and Bos d5 levels. In conclusion, the HP product was tolerated by 72% of the CM allergic children. Outcomes of SPT with CM and the HP product, as well as values of sIgE against caseins, α-lactalbumin, and ß-lactoglobulin may predict the tolerability of the HP product. Larger studies are needed to confirm these conclusions.

Extremely low prevalence of epinephrine autoinjectors in high-risk food-allergic adolescents in Dutch high schools.

The aim of the study was to estimate the prevalence of probable food allergy in adolescents aged 11-20 and to examine the frequency of epinephrine autoinjector (EAI) ownership among high-risk individuals. Adolescents were screened followed by a more detailed telephone questionnaire inquiring about suspected food(s), symptoms, diagnosis, and use of an EAI. The participating adolescents were classified as probably or unlikely to be food-allergic. The need for an EAI was assessed. In total, 2284 adolescents completed the screening questionnaire, of which 396 indicated food to be a problem and 168 agreed to be interviewed. Forty-eight adolescents were classified as probably food-allergic, of which eight were not aware of their food allergy. Twenty-three adolescents were considered candidates for an EAI, whereas only two of them had been prescribed this medication. The calculated questionnaire-based prevalence of EAI need was 3.0% (minimal prevalence at least 1.0%), whereas the EAI ownership was 0.09%. In conclusion, we found an alarming under prescription of EAIs in school-going adolescents.

Successful introduction of milk after a negative double-blind placebo-controlled food challenge test is independent of the total dose and milk product used during the challenge test.

BACKGROUND: Failure of milk introduction after a negative food challenge test is reported in a substantial number of patients. For this reason, guidelines recommend that the total dose of milk protein for a food challenge test should be comparable to a normal serving. OBJECTIVE: Our aim is to compare the success rate of milk introduction after a negative double-blind placebo-controlled challenge test performed with different doses of milk protein and different milk products. METHODS: We conducted a retrospective chart review of 485 patients challenged with a low or high dose of milk protein. Pasteurized milk and milk protein powder were used for the low-dose challenge tests, and condensed milk for the high-dose challenge tests. Successful introduction was defined as regular milk consumption, and discontinuation of further introduction due to the reappearance of symptoms as unsuccessful introduction. We also evaluated the association between milk products and successful introduction. RESULTS: The outcome of 288 (59.4%) double-blind placebo-controlled food challenge tests was negative. There were no significant differences between the low and high dose of milk protein in patient characteristics, percentage of patients lost to follow-up (15% vs 20%), in whom introduction had not yet been performed (4% vs 3.1%), reappearance of symptoms (18% vs 17%), and successful introduction (88.0% and 83.4%). Age, gender, specific immunoglobulin E for milk, dose of milk protein, and atopy were not associated with successful introduction. Children who experienced symptoms during the introduction were less likely to consume milk (P < .001). There was a nonsignificant trend toward higher successful introduction rate if pasteurized milk was used as test material compared to milk protein powder, and condensed milk. CONCLUSION AND CLINICAL RELEVANCE: Successful introduction of milk after a negative challenge test is independent of the total dose of milk protein, and milk product used during the challenge test.