Determination of the clinical egg allergy phenotypes using component‐resolved diagnostics

IgE‐mediated egg allergy presents as one of the most common food allergies in children and is a food which is widely consumed all over the world. Measurement of egg white‐specific IgE levels has been shown to be a poor predictor of clinical phenotypes of egg allergy, including to raw egg white, but particularly to baked or cooked egg. Egg white and yolk contain more than 20 different glycoproteins, including ovomucoid, ovalbumin, ovotransferrin, alpha‐livetin, and the newly identified Gal d 6. Recent developments in component‐resolved diagnostic technology, including microarrays, have enabled us to improve the way in which we diagnose food allergy. This technology allows us to measure specific IgE antibodies to individual egg allergens which have been highly purified. Characterization of the major egg allergens could help profile the relevant binding epitopes to each region and may also help diagnose the different clinical phenotypes of egg allergy.     

Oral immunotherapy in hen’s egg‐allergic children increases a hypo‐proliferative subset of CD4+ T cells that could constitute a marker of tolerance achievement

Background: Food allergy affects a significant number of children and its prevalence, and persistence is undergoing an important increase in the last years. Specific oral tolerance induction (SOTI) is a promising therapy for food allergy. However, little is known about the immune mechanisms implicated in the desensitization to allergens. Our purpose was to study which immune parameters are modified during the process of tolerance achievement with the goal of identifying markers of tolerance induction. Methods: We performed an extensive immune analysis in 19 allergic children following SOTI with hen’s egg before and after the immunotherapy. Changes in lymphocyte subpopulations and serum cytokines were identified in children with desensitization achievement. Results: Sixteen children achieved complete tolerance to egg, and the immune analysis reveals that desensitization was accompanied in all the cases by a significant decrease in the percentage and absolute counts of effector‐memory CD4+ T cells (T_EM) and a marked increase in the absolute counts of a subset of CD4⁺CD38⁺CD45RO^? cells. Additionally, we also observed a marked reduction in the plasma levels of different Th1 and Th2 cytokines after tolerance achievement. Conclusions: Acquisition of tolerance in children after oral immunotherapy is accompanied by a decrease in the T_EM population and the increase in a particular subset of CD4+ T cells with a hypo‐proliferative and non‐reactive phenotype. This hypo‐proliferative subset of cells could constitute a marker of the development of oral tolerance, and the study of this subset could contribute to the better understanding of the immune responses in allergic subjects.     

Protein‐losing enteropathy and erythema caused by egg allergy in a breast‐fed infant

A 4‐month‐old breast‐fed girl presented with poor weight gain, and had edema and repeated erythema from 5 months of age. The diagnosis of protein‐losing enteropathy (PLE) was confirmed on ^99mTc‐labeled human serum albumin scintigraphy. Specific IgE radioallergosorbent test was class 3 for egg white, class 2 for egg yolk, and negative for other foods. Elimination of egg from the mother's diet and oral epinastine hydrochloride treatment and sodium cromolyn improved hypoalbuminemia, hypogammaglobulinemia, and erythema. PLE and erythema coincident in a breast‐fed infant suggests that IgE‐mediated allergy may play a leading role in some cases of PLE due to food allergy in infants.     

IgE and atopy in perinatally HIV-infected children

Elevated serum immunoglobulin E (IgE) and increased prevalence of atopy is reported in patients infected with human immunodeficiency virus (HIV). The elevated serum IgE may be attributed to polyclonal stimulation of B cells or IgE production against allergens, viruses, fungi and bacteria. This study investigates the prevalence of atopy in perinatally HIV-infected children, and the relationships between serum IgE (and other serum immunoglobulins) with atopy, CD4+ cell count and HIV-disease stage. Serum immunoglobulin levels, epicutaneous skin test for common aeroallergens, clinical Centers for Disease Control and Prevention (CDC) classification, CD4+ cell counts and allergy history were extracted from the charts of perinatally HIV-infected children on highly active antiretroviral therapy. The prevalence of atopy (52%) and the pattern of aeroallergen sensitivity were comparable with the US pediatric population. Serum IgE levels did not correlate with clinical disease stage. However, in non-atopic patients, serum IgE levels increased with disease progression (p = 0.02). There was an inverse relationship between the prevalence of elevated serum IgE levels and atopy with progression of disease (p = 0.019). Serum IgE did not correlate with atopy, CD4+ cell count, or duration of HIV infection or levels of serum immunoglobulins. This is the first study to show no increased prevalence of atopy in perinatally HIV-infected children compared with the general population. In advanced stages of HIV, elevated serum IgE may be specific for antigens other than those known as allergens.     

Questionnaire‐based survey of lifetime‐prevalence and character of allergic drug reactions in German children

Data on the epidemiology of adverse drug reactions (ADR), especially allergic drug reactions, in children are rare. The reported prevalence of ADR in pediatric populations varies a lot, depending on type of the study and the country where the data were collected. In order to assess the prevalence of ADR and allergic drug reactions in a population of German children, we conducted a study in a German pediatric university hospital. A questionnaire concerning occurrence and character of ADR was distributed to all parents presenting their children in the hospital for planned admissions or in the emergency department from May 2004 to November 2004. Additional telephone interviews were conducted to specify the reported symptoms in ambiguous cases. One thousand four hundred forty‐seven questionnaires were collected. The reported life‐time prevalence of ADR according to the information given by the parents was 7.5% (108/1447). Six of the reactions were severe, three children had experienced anaphylactic reactions. In 4.2% (61/1447), the history was suspicious for a potential allergic mechanism because of an immediate or late phase cutaneous drug reaction. In this group, the suspected drugs were antibiotics in 85% (32.7% aminopenicillins, 29.5% other penicillins, 11.5% cefaclor, 8.2% macrolides and 18% others), antiphlogistic and respiratory drugs in 4.9% each and vaccines and contrast media in 3.3% each. There was a higher percentage of children under the age of four suffering from ADR. This trend was not significant when analyzing only the allergic reactions. Forty‐four percent of the parents stated, their children suffer from drug allergy, although a clear non‐allergic reaction was described. Both, ADR and allergic drug reactions are frequent phenomena in children. It is important to monitor drug therapy for any adverse reaction in order to inform the parents about the character of the adverse reaction, the necessary consequences and to initiate further diagnostic procedures.     

Quantification of IgE antibodies simplifies the classification of allergic diseases in 4-year-old children. A report from the prospective birth cohort study – BAMSE

Allergic diseases are common among small children, but it is still unclear how immunoglobulin E (IgE) antibodies to ambient allergens are distributed in a population‐based prospective material of children at 4 years of age. The study is based on 75% (n = 4089) of all eligible children from northern Stockholm, born between 1994 and 1996 in pre‐defined geographical areas. Data on exposure and outcome were obtained by parental questionnaires when the child was 3 months and 4 years of age. Of the 92% who responded to the 4 years of age questionnaire, serum was obtained in 88% of these children for analysis of IgE antibodies performed with Pharmacia CAP system^TM (Phadiatop^® and food mix fx5^®). An antibody level ≥0.35 kU_A/l was considered as positive. A positive Phadiatop^® or fx5^® was found in 24% of the 4 years old children. A rather poor correlation was found between the two tests (r = 0.39). Occurrence of IgE antibodies ≥3.5 kU/l for both Phadiatop^® and fx5^® in combination could predict any suspected allergic disease [asthma, rhinitis, atopic eczema dermatitis syndrome (AEDS) and allergic reaction to food] to 97.4%. However, the presence of ≥3.5 kU_A/l of Phadiatop^® or fx5^® used as single tests only, was far less efficient to predict any allergic disease. The two mixes of airborne and food allergens were also associated, not only to the severity of the allergic disease in terms of number of organ involved, but also to the severity of recurrent wheeze, in particular in boys with a positive Phadiatop^® who exhibited significantly limited peak flows compared to those with a negative test. Already at the age of 4, one child in four is sensitized to an allergen as assessed by Phadiatop^® or food mix (fx5^®). The presence of IgE antibodies seems not only to predict allergic diseases in this age group, but also relates to severity of such diseases, in particular to asthma. Notable, there was a poor correlation between Phadiatop^® and fx5^® that needs to be considered when identifying allergic diseases in young children. The study demonstrates that quantification of IgE antibodies in blood may be beneficial, not only to diagnose allergic diseases in young children, but especially to serve as a marker of severity of asthma.     

Food allergy knowledge,attitudes, and beliefs of parents with food‐allergic children in the United States

Gupta RS, Springston EE, Smith B, Kim JS, Pongracic JA, Wang X, Holl J. Food allergy knowledge, attitudes, and beliefs of parents with food‐allergic children in the United States.
Pediatr Allergy Immunol 2010: 21: 927–934.
© 2010 John Wiley & Sons A/S Parents of food‐allergic children are responsible for risk assessment and management of their child’s condition. Such practices are likely informed by parental knowledge, attitudes, and beliefs of food allergy. Our objective was to characterize food allergy knowledge and perceptions among parents with food‐allergic children. Parents were recruited nationally between January 2008 and 2009 to complete the validated, web‐based Chicago Food Allergy Research Survey for Parents of Children with Food Allergy. Findings were analyzed to provide composite/itemized knowledge scores, describe attitudes and beliefs, and examine the effects of participant characteristics on response. A sample of 2945 parents was obtained. Participants had an average knowledge score of 75% correct (range 19–100%). Strengths were observed in each content domain; e.g., 95% of participants accurately identified the signs of a milk‐induced reaction. Weaknesses were limited to items assessing food allergy triggers/environmental risks and perceptions of susceptibility/prevalence; e.g., 52% of parents incorrectly believed young children are at higher risk for fatal anaphylaxis than adolescents. Parental attitudes/beliefs were diverse, although 85% agreed children should carry an EpiPen at school and 91% felt schools should have staff trained in food allergy. One in four parents reported food allergy caused a strain on their marriage/relationship, and 40% reported experiencing hostility from other parents when trying to accommodate their child’s food allergy. In conclusion, parents in our study exhibited solid baseline knowledge although several important misconceptions were identified. While a broad spectrum of parental perceptions was observed, a large proportion of parents reported that their child’s food allergy had an adverse impact on personal relationships and also agreed on certain policies to address food allergy in schools.     

Fish intake during pregnancy or infancy and allergic outcomes in children: A systematic review and meta‐analysis

It has been suggested that n‐3 long‐chain polyunsaturated fatty acids (n‐3 LC‐PUFAs) have anti‐inflammatory properties and may reduce the risk of allergic disease. Fish is a great source of n‐3 LC‐PUFAs. However, the effect of fish on allergic disease remains controversial. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) and prospective cohort studies regarding the effect of fish intake during pregnancy or infancy on allergic outcomes in children. The outcomes of interest were atopy, eczema, allergic rhinitis, wheeze, asthma, and food allergy. One RCT and 17 publications from 13 prospective cohort studies were included for maternal fish intake during pregnancy, and eight publications from five prospective cohort studies for fish intake in infancy. Pooled analysis suggested that maternal fish intake during pregnancy was not associated with lower risk of any allergic outcome, both in RCT and observational studies. Consumption of fish during the first year of life reduced the risk of eczema (RR 0.61; 95% CI 0.47, 0.80; p = 0.0003; I² = 68%) and allergic rhinitis (RR 0.54; 95% CI 0.36, 0.81; p = 0.003; I² = 74%). Current evidence indicates that fish intake in infancy could reduce the risk of eczema and allergic rhinitis in children, whereas maternal fish intake during pregnancy does not affect any atopic outcome. The intake of fish per se in infancy, not specially n‐3 LC‐PUFAs, may have an allergy protective effect. High‐quality and adequately powered RCTs are warranted to confirm this.