Health-related quality of life in children with objectively diagnosed staple food allergy assessed with a disease-specific questionnaire.

AIM: Among Swedish children of 0-12 years old, we investigated various food allergy-related exposures associated with health-related quality of life using a food allergy-specific questionnaire among children allergic to the staple foods cow's milk, hen's egg and/or wheat, and contextualised worse food allergy-associated health-related quality of life using a generic questionnaire versus controls. METHODS: In total, 85 children with objectively diagnosed allergy to the staple foods were included as cases, and 94 children matched for age and sex were included as controls. We administered a food allergy-specific parent-completed questionnaire originally developed by EuroPrevall to cases only, and a generic health-related quality of life questionnaire (EuroQol Health Questionnaire, 5 Dimensions; EQ 5-D); to both cases and controls. RESULTS: Hen's egg was the most common offending staple food, affecting 76% of cases. Approximately 7% of cases were allergic to all three staple foods. Parent-reported respiratory and cardiovascular symptoms were associated with worse health-related quality of life. Elements of disease severity [previous anaphylaxis (p < 0.001); epinephrine autoinjector prescription (p < 0.003)] were negatively associated with health-related quality of life. Cases had worse health-related quality of life measured by the EQ-5D compared to controls (p < 0.01). CONCLUSION: The use of a disease-specific questionnaire revealed that disease severity in children with objectively diagnosed allergy to the staple foods cow's milk, hen's egg and/or wheat is associated with worse health-related quality of life. The use of a generic questionnaire confirmed that cases have worse health-related quality of life than controls.

Socioeconomic evaluation of well-characterized allergy to staple foods in adults.

BACKGROUND: The aim of the present study was to evaluate if total, direct, indirect, and intangible costs differ between a cohort of adults with well-characterized allergy to staple foods ('cases') and controls. METHODS: Swedish adults with objectively diagnosed food allergy to cow's milk, hen's egg, and/or wheat were recruited at an outpatient allergy clinic. Controls age- and sex-matched to cases were recruited from the same geographic area. For assessing the household costs of food allergy, a disease-specific socioeconomic questionnaire, developed within EuroPrevall, was utilized. RESULTS: Overall annual total costs at the household level were significantly higher among adults with food allergy compared with controls (the difference amounted to 8164 €), whereas direct costs did not differ between cases and controls. However, household healthcare costs and costs for medicines were significantly higher for cases vs controls. Furthermore, indirect costs were significantly higher for households with food-allergic adults vs households without food-allergic adults. Specifically, more time was spent on performing domestic tasks due to a family member's food-allergy-related illness, as well as shopping and preparing food, and seeking food-allergy-related information. Presence of food allergy also affected intangible costs. Adults with food allergy experienced overall lower health status compared with controls. CONCLUSIONS: Swedish adults with allergy to staple foods have higher total costs determined as direct, indirect, and intangible costs using the disease-specific socioeconomic questionnaire. Thus, total costs were 8164 € higher per year in households with at least one adult allergic to staple foods compared with controls.

Has the increase in the prevalence of asthma and respiratory symptoms reached a plateau in Stockholm, Sweden?

SETTING: An increase in the prevalence of asthma has previously been reported worldwide. However, the current trend is debatable. OBJECTIVE: To assess changes in the prevalence of asthma and respiratory symptoms in a defined study area in Stockholm, Sweden, using identical methods. DESIGN: A questionnaire was sent by mail in 1996 and 2007 to randomly selected subjects aged 20-69 years. On both occasions, 8000 subjects received the questionnaire, with response rates of 72% and 68%, respectively. Questions on asthma, respiratory symptoms, asthma medication and possible determinants were included. Logistic regression analysis was used to assess determinants. RESULTS: Ever asthma increased from 8.7% in 1996 to 11.0% in 2007 and physician-diagnosed asthma from 7.6% to 9.3%. The proportion of asthma patients reporting one to two symptoms increased by 14% during the study period. There were few significant changes in the prevalence of respiratory symptoms: wheeze in the previous 12 months (15.9-17.3%), wheezing with breathlessness apart from cold (3.2-4.1%) and recurrent wheeze (8.3-6.8%). There was no major difference in the risk factor pattern between the surveys. CONCLUSION: An increase in the prevalence of asthma with few symptoms as well as an unchanged prevalence of symptoms was demonstrated, which may indicate a change in diagnostic practices.

Asthma prediction in school children; the value of combined IgE-antibodies and obstructive airways disease severity score.

BACKGROUND: Allergic sensitisation increases the risk for asthma development. In this prospective birth cohort (Environment and Childhood Asthma) study, we hypothesized that combining quantitative measures of IgE antibodies (Sigma-IgE) and Severity score of obstructive airways disease (OAD) at 2 years of age (Severity score) is superior to predict current asthma (CA) at 10 years than either measure alone. Secondarily, we assessed if gender modified the prediction of CA. METHODS: A follow-up study at 10 years of age was performed in 371 2-year-old children with recurrent (n = 219) or no (n = 152) bronchial obstruction with available serum analysed for Sigma-IgE to common food and inhalant allergens through a panel test, Phadiatop Infant) (Phadia, Uppsala, Sweden). Clinical variables included allergic sensitisation and exercise testing to characterise children with CA vs not CA at 10 years and the Severity score (0-12, 0 indicating no OAD) was used to assess risk modification. RESULTS: Severity score alone explained 24% (Nagelkerke R(2) = 0.24) of the variation in CA, whereas Sigma-IgE explained only 6% (R(2) = 0.06). Combining the two increased the explanatory capacity to R(2) = 0.30. Gender interacted significantly with Sigma-IgE; whereas Severity score predicted CA in both genders, the predictive capacity of Sigma-IgE for CA at 10 years was significant in boys only. CONCLUSION: Combining Sigma-IgE to inhalant allergens and Severity score at 2 years was superior to predict asthma at 10 years than either alone. Severity score predicted CA in both genders, whereas Sigma-IgE significantly predicted CA in boys only.

IgE to peanut allergen components: relation to peanut symptoms and pollen sensitization in 8-year-olds.

BACKGROUND: Allergen-specific IgE testing is often performed with crude peanut extract, but the results may be difficult to interpret because of cross-reactions between peanut and other plant allergens. The aim was to investigate IgE reactivity to peanut allergen components in children from a birch-rich region in relation to pollen sensitization and peanut symptoms. METHODS: From a birth cohort, clinical parameters were obtained through questionnaires and IgE antibody levels to peanut and birch pollen were measured. Different peanut/birch sensitization phenotypes were defined among 200 selected children. IgE reactivity to peanut and pollen allergen components was analysed using microarray technique. RESULTS: Peanut symptoms were reported in 87% of the children with IgE reactivity to any of the peanut allergens Ara h 1, 2 or 3 but not to Ara h 8 (n = 46) vs 17% of children with IgE reactivity to Ara h 8 but not to Ara h 1, 2 or 3 (n = 23), P < 0.001. Furthermore, symptoms were more severe in children with Ara h 1, 2 or 3 reactivity. Children with IgE reactivity both to Ara h 2 and to Ara h 1 or 3 more often reported peanut symptoms than children with IgE only to Ara h 2 (97%vs 70%, P = 0.016), particularly respiratory symptoms (50%vs 9%, P = 0.002). CONCLUSIONS: IgE analysis to peanut allergen components may be used to distinguish between peanut-sensitized individuals at risk of severe symptoms and those likely to have milder or no symptoms to peanut if sensitized to pollen allergens and their peanut homologue allergens.

Th2-associated immunity to bacteria in teenagers and susceptibility to asthma.

Bacterial colonisation of the airways is associated with increased risk of childhood asthma. Immunoglobulin (Ig)E against bacterial antigens has been reported in some asthmatics, suggesting a role for bacterial-specific type-2 immunity in disease pathogenesis. We aimed to investigate relationships between bacterial-specific IgE amongst teenagers and asthma susceptibility. We measured titres of IgE against Haemophilus influenzae, Streptococcus pneumoniae and Staphylococcus aureus in 1,380 teenagers, and related these to asthma symptomatology and immunophenotypes. IgE titres against S. aureus-derived enterotoxins were highest amongst atopics and were associated with asthma risk. Surprisingly, IgE titres against H. influenzae and S. pneumoniae surface antigens were higher, not stratified by atopy and independently associated with decreased asthma risk. The positive association between type-2 immunity to S. aureus and asthma phenotypes probably reflects IgE-mediated effector cell activation via enterotoxin super antigens which are secreted in soluble form. The contrasting benign nature of type-2 immunity to H. influenzae and S. pneumoniae antigens may reflect their lower availability in soluble forms that can crosslink IgE receptors. We theorise that instead they may be processed by antigen presenting cells and presented to type-2 memory cells leading to mucosal secretion of interleukin (IL)-4/IL-13, a mechanism widely recognised in other tissues to attenuate T-helper-1 associated bacterial-induced inflammation.

Reported symptoms to peanut between 4 and 8 years among children sensitized to peanut and birch pollen - results from the BAMSE birth cohort.

BACKGROUND: Specific IgE tests are sometimes difficult to interpret due to structural similarities between certain food and pollen allergens. This may be the reason why concomitant sensitization to peanut and birch pollen is frequently seen. The aim of this study was to investigate reported symptoms to peanut- and birch pollen in relation to sensitization. METHODS: The data originate from 1928 children in the BAMSE birth cohort. Background factors and clinical parameters were obtained and the levels of IgE antibodies to peanut and birch pollen measured at 4 and 8 years. RESULTS: IgE antibodies to peanut were found in 5.5% and 7.4% of the children at 4 and 8 years, respectively. The IgE antibody levels to peanut were higher in children sensitized to peanut but not birch than in children sensitized to peanut and birch among both 4- and 8-year-olds (P = 0.093 and P = 0.003, respectively). Eight-year-olds sensitized to peanut but not birch, more often reported symptoms to peanut than children sensitized to both peanut and birch pollen (76%vs 46%, P = 0.002). The probability of reported symptoms to peanut increased significantly with increasing IgE levels to peanut, especially in 8-year-olds not sensitized to birch. CONCLUSIONS: Children sensitized to both peanut and birch pollen are less likely to report symptoms to peanut than children sensitized to peanut but not to birch pollen at 8 years. This is likely due to cross reactions between birch pollen and peanut and can explain the high sensitization rate to peanut in areas where birch trees are common.

Primary care: the cornerstone of diagnosis of allergic rhinitis.

Allergic rhinitis (AR) is a very common disease with over 600 million people (200 million of them with concomitant asthma) worldwide suffering from it. The majority of patients who seek medical advice are seen in primary care. Although there is a selection of guidelines focused on the management of AR, there is a paucity of guidance on how best to identify patients who would most benefit from treatment. The aim of this paper was to review the best practice for primary care with respect to the diagnosis of AR within that clinical environment.

Patterns of quantitative food-specific IgE-antibodies and reported food hypersensitivity in 4-year-old children.

BACKGROUND: Diagnosis of food hypersensitivity (FHS) is difficult and interpretation of food allergy tests is complicated. OBJECTIVE: To investigate the probability of reported FHS in relation to levels of food-specific IgE-antibodies (AB) in a population-based setting of 4-year-old children (n = 2336). METHODS: Information on FHS was obtained from a questionnaire and specific IgE-AB to milk, egg, fish, peanut, soy and wheat were analysed. RESULTS: Thirty-one per cent of the children with reported FHS (n = 284) were sensitized (> or =0.35 kU(A)/l) to at least one of the tested foods compared with 11% of children without FHS (n = 2052). Furthermore, the probability of reported symptoms to milk, egg and fish increased with increasing levels of food-specific IgE-AB to the same food allergens. A similar trend was seen for peanut and wheat, but not for soy. Increasing levels of specific IgE-AB to milk or egg were also associated with an increasing risk of reported symptoms caused by other foods. CONCLUSIONS: Quantitative measurements of IgE-AB to milk, egg and fish are useful to evaluate IgE-associated FHS in preschool children also in a population based sample. Such measurements appear to be of limited value for soy bean and wheat, in particular as a screening method.

Detection of local mast-cell activity in patients with food hypersensitivity.

BACKGROUND: Mast cells play a central role in many inflammatory diseases and assessment of their activation may be of use to provide objective confirmation of the outcome of food challenge in the diagnosis of food hypersensitivity. However, to date, assessment of mast-cell activation using serum markers has been unsuccessful. OBJECTIVE: The aim of this study was to explore whether locally released tryptase could be detected in stool samples from patients with food hypersensitivity. METHODS: Nine patients (median age, 55 years; range, 26 - 68 years) with food hypersensitivity confirmed by double-blind placebo-controlled food challenge were included in the study. Tryptase concentration was assessed in stool samples collected before and after an open food challenge at home and symptoms were recorded throughout the study. Tryptase concentration was also assessed in stool samples from 16 apparently healthy individuals (median age, 44 years; range, 27 - 72 years). RESULTS: Measurement of fecal tryptase levels in 16 healthy control subjects revealed an upper limit of the normal range (mean + 2 SD of log transformed data) of 10 ng/g. Fecal tryptase levels exceeded 10 ng/g in 7 out of 9 patients in one or more samples obtained during the study. The tryptase levels varied between patients in response to the food challenge and the individual mean levels of tryptase correlated with the corresponding levels of the inflammatory marker eosinophil protein X (rho = 0.7500, P = .02). CONCLUSION: Measurement of tryptase levels in stool samples is feasible using the method described here. Our results revealed elevated concentrations of fecal tryptase in patients with food hypersensitivity. However, several factors, including food exposure, may account for the increase in fecal tryptase and further studies are necessary to elucidate the role of mast cells in food hypersensitivity.

Quantification of atopy and the probability of rhinitis in preschool children: a population-based birth cohort study.

BACKGROUND: Atopy quantification using IgE levels/skin test diameter (SPT-MWD) may better predict the expression of rhinitis than using atopy as a dichotomous variable. OBJECTIVE: To investigate the association between the presence, temporal pattern and severity of rhinitis in preschool children and specific IgE levels/SPT-MWDs. METHODS: Children were followed prospectively to age 5 years in a whole-population birth cohort study. We administered questionnaires (n = 815), skin prick tested children (n = 717) and measured specific serum IgE (n = 478) to inhalant and food allergens. Main outcomes were current rhinitis (CR) and current rhinoconjunctivitis (CRC). RESULTS: The prevalence of CR and CRC was 26.1% and 12.1%, respectively. The risk of CR and CRC increased significantly with increasing IgE to grass, mite and cat; CRC was also associated with increasing IgE to dog and peanut. Similarly, increasing SPT-MWDs to inhalant allergens were significantly associated with CR and CRC. This association was also shown for grass within the group of atopic children. Perennial and seasonal rhinitis were associated with increasing IgE/SPT-MWD to mite and grass, respectively. Moderate/severe rhinitis was associated with increasing IgE/SPT-MWD to grass. In a multivariate analysis, increasing levels of IgE/SPT-MWD to grass were the strongest independent predictors of both CR (for IgE: OR 1.42, 95% CI 1.23-1.64, P < 0.001) and CRC (for IgE: 1.51, 1.30-1.76, P < 0.001). CONCLUSION: The probability of CR/CRC increases with increasing specific IgE levels or SPT-MWD. With respect to allergic rhinitis, the absolute levels of specific IgE antibody or the size of SPT wheal offer more information than just the presence/absence of sensitization.

Immunoglobulin constant heavy G chain genes as risk factors in childhood allergies.

BACKGROUND: Several candidate genes have been found to be associated with the inflammatory response of IgE-mediated allergy, so also the immunoglobulin constant heavy G chain (IGHG) genes. The IGHG genes are situated close to the IGHE gene on chromosome 14q32, 5'mu, delta, gamma3, gamma1, alpha1, gamma2, gamma4, epsilon, alpha2, 3'. They are inherited in a Mendelian fashion and expressed randomly in allelic exclusion. The alternative and functionally different gamma3, gamma1 and gamma2 gene variants are found in four IGHG haplotypes, coding four B cell variants. OBJECTIVE: The aim of this study was to assess the frequency of different IGHG genes in relation to phenotypes associated with allergy, in a case-control study. METHODS: We identified the constant heavy-chain genes of IgG in 198 allergic and non-allergic children participating in the Phase II of the International Study of Asthma and Allergy in Children. The IGHG genes were assessed by the alternative serum IgG subclass allotypes expressing the alternative alleles of gamma3, gamma1 and gamma2 genes, using ELISA and double immunodiffusion. RESULTS: The IGHG*bfn haplotype (=B1 cells) and IGHG2*n allele dominated (51% vs. 24%, P=0.002) and the IGHG*bf-n haplotype (=B2 cells) was infrequent (16% vs. 52%, P < 0.001) in allergic children with a family history of allergy, clinical manifest allergy and positive skin prick test (SPT). The frequency of IGHG genes was similar in children with maternal and paternal heredity and in children with wheezing, eczema or rhinitis, as well as in children with different positive SPT. The IGHG*bfn haplotype with the IGHG2*n allele was strongly associated with heredity for allergy. The IGHG*bf-n haplotype was inversely related to allergy. Conclusions IgG allotypes, immunochemical and functional variants of IgG molecules from IGHG genes are associated with atopy. The IGHG*bfn haplotype (=B1 cells) with the IGHG2*n allele dominates, associated with an increased risk for atopy. In contrast, the IGHG*bf-n haplotype (=B2 cells) with the IGHG2*-n allele is associated with low risk.

Release of prostaglandin D2 and leukotriene C4 in response to hyperosmolar stimulation of mast cells.

BACKGROUND: Mannitol-induced bronchoconstriction in subjects with exercise-induced asthma is associated with increased urinary excretion of 9alpha, 11beta-PGF(2), a metabolite of prostaglandin D(2) (PGD(2)) serving as a mast cell marker. It has however been questioned whether or not human mast cells release PGD(2) and leukotriene C(4) (LTC(4)) after osmotic challenge with mannitol in vitro. METHODS: Cord blood-derived human mast cells were stimulated osmotically, immunologically or with a combination of both. Supernatants were analysed for PGD(2), LTC(4) and histamine contents with enzyme immunoassays. RESULTS: Significant release of de novo synthesized eicosanoids, predominantly PGD(2) [12 (8.8, 14) pmol/10(6)cells; median (25th, 75th percentile) but also LTC(4) (0.1 (0.08, 0.15) pmol/10(6) cells] were found in mast cells in vitro in response to 0.7 M mannitol stimulation. A massive release of histamine [70 (5.3)% of total; mean (SEM)] was also found. There were no correlations between the levels of released mediators after mannitol stimulation. In contrast, there was a correlation between release of PGD(2) and LTC(4), following immunological stimulation. CONCLUSION: The findings support that hyperosmolar challenge activates mast cells, but different than antigen stimulation.

Measurements of eosinophil activation before and after food challenges in adults with food hypersensitivity.

BACKGROUND: Objective assessment of inflammatory reactions in the gastrointestinal tract could be useful in the diagnosis of food hypersensitivity. The aim of the present study was to investigate the involvement of eosinophils and mast cells in the inflammatory response of patients with food hypersensitivity before and after food challenges. METHODS: Eleven patients (4 with IgE-mediated allergy and 7 without) with food hypersensitivity and positive double-blind, placebo-controlled food challenge were subjected to food challenge in a single-blinded fashion. Four subjects with no known food hypersensitivity were recruited as controls. Placebo was given after a 1-week washout period followed by an active dose. Stool, urinary and serum samples were collected and symptoms were recorded in a diary. Fecal samples were analyzed for eosinophil protein X (F-EPX) and tryptase; urinary samples for EPX (U-EPX) and leukotriene E4 (U-LTE4) and serum samples were analyzed for eotaxin and food-specific IgE antibodies. RESULTS: Patients with IgE-mediated food allergy had increased levels of F-EPX compared to controls and tended to have lower serum levels of eotaxin compared to non-allergic patients and controls. U-LTE4 was significantly higher in allergic patients compared to non-allergic patients after challenge. Moreover, F-EPX correlated to U-LTE4 (p = 0.011). Reported symptoms, abdominal pain, distension, flatulence and nausea were similar in the allergic and non-allergic patients. CONCLUSION: The results strongly indicate that eosinophils are activated in the gastrointestinal tract of food-allergic patients but not in patients with non-allergic food hypersensitivity. Due to the inconsistent pattern of symptoms after placebo and active food challenge, it was not possible to relate the levels of inflammation markers to the recorded symptoms.

Sensitization to different pollens and allergic disease in 4-year-old Swedish children.

BACKGROUND: Although the relationship between sensitization to different inhalant allergens in adolescents and adults has been intensively studied, information concerning sensitization in children is scarce in particular to pollens. OBJECTIVES: In 4-year-old children to elucidate the pollen immunoglobulin (IgE) antibody profile (birch only, timothy only and combinations of three pollens (birch, timothy or mugwort) and to relate the results to other inhalant and food allergens, as well as the presence of allergic diseases. METHODS: A total of 2551 4-year-old children belonging to a prospective birth cohort, which has been followed longitudinally (BAMSE), were investigated with respect to IgE antibodies to pollen and other inhalant and food allergens, and expression of allergic disease, based on questionnaire data. RESULTS: Eleven percent (n=285) of the children were sensitized to pollen. Birch was the dominating cause of pollen sensitization (birch sensitization only, n=133); followed by timothy grass pollen (n=56) and a combination of two (n=64) or three (n=30) pollens. A remarkably high proportion of the children sensitized only to birch was also sensitized to other inhalant allergens. This was not seen for children sensitized only to timothy. The highest frequencies of IgE reactivity to food were found in the group of children sensitized to the combination of birch, timothy and mugwort pollen. Children sensitized to timothy only, exhibited symptoms of allergic disease significantly less frequently compared with children sensitized to birch only. Sensitization to birch pollen was found to be closely associated with rhinitis and eczema compared with asthma. The highest frequency of asthma and/or rhinitis and/or eczema was reported in children sensitized to at least two pollens. CONCLUSION: Our results demonstrate that birch is the dominating source of pollen sensitization at the age of four in Sweden. This might associate with the pattern of sensitization to other inhalant and food allergens as well as influence on the expression of allergic disease in this particular age group.

Double-blind placebo-controlled challenges for peanut allergy the efficiency of blinding procedures and the allergenic activity of peanut availability in the recipes.

BACKGROUND: A firm diagnosis of double-blind placebo-controlled food challenge (DBPCFC) would facilitate the diagnosis in patients with uncertain history of reaction. Guidelines are lacking for an upper provoking dose and how to hide high concentrations of peanuts. AIM: To develop and evaluate a double-blind recipe with minimum 10% of peanut. To compare the recipe with published recipes regarding blindness, taste, texture and immunoglobulin (Ig)E antibody binding to peanut. METHODS: A recipe (I) with 10% of peanut was developed evaluated and used in DBPCFC. The challenges were followed by development of a concentrated recipe (II) (15% peanut, 25% fat). Recipe II was compared with the only published recipe (III) (11% peanut, 7% fat) regarding taste, texture and availability of peanut. Recipe IV (12% peanut, 10% fat) was developed using the same methods. The binding of IgE in the recipes was measured using an inhibition method. RESULTS: During challenges, one patient reacted after 4 g, emphasizing the need for blinding recipes containing high doses of peanut. Evaluation between recipes II and III, only recipe II was regarded as blind by the taste panels. A tenfold lower availability of peanut protein in the recipe II was found at 50% of inhibition. Recipe IV had a better IgE binding that did not differ from the original peanut extract. CONCLUSION: The peanut taste and texture can be hidden in a challenge medium. The fat content was important for the availability of the allergenic protein in challenges. The availability of allergens must be taken into consideration when used for DBPCFC.

Quantitative analysis of IgE antibodies to food and inhalant allergens in 4-year-old children reflects their likelihood of allergic disease.

BACKGROUND: It is well established that early diagnosis of allergic disease is warranted. METHODS: In a prospective birth cohort study (BAMSE) 3743 children at 4 years of age were included. Children were classified as having any allergic disease, e.g. asthma, suspected allergic rhinitis (suspAR), eczema or oro-gastro-intestinal symptoms with questionnaire. Blood was obtained from 2612 of these children and analysed for IgE antibodies (ab) towards 14 common food and airborne allergens. RESULTS: Positive IgE ab results were found in 38% of the children with any allergic disease, whereas such IgE ab results were found in 17% among those without any allergic disease. Furthermore, among children with any allergic disease the median summated IgE ab levels were 10.7 kU(A)/l compared with 1.5 kU(A)/l among those without such symptoms. The highest IgE ab levels were found to birch, peanut, cat and horse. When the sum of the IgE-ab levels towards the selected allergens was at least 34 kU(A)/l, or, alternatively, more than four allergen tests were positive, there was a 75% likelihood of identifying the individual with any allergic disease. To identify those with asthma, as well as those with suspAR, a significant interaction was found for the combination of the sum of IgE-ab levels and number of allergens positive at test. For eczema only, the number of positive allergens at test was associated to the likelihood of such disease. CONCLUSIONS: In children, 4 years of age, allergic disease was frequently not associated with the presence of single positive IgE antibody results, whereas increased IgE ab levels were significantly more prevalent among those with allergic disease. Thus, testing a certain profile of airborne and food allergens, and utilizing the sum of the IgE-ab levels in combination with the number of allergens positive at tests, may represent a more efficient diagnostic tool then to use just single positive IgE-ab results.

Antibody profiles and self-reported symptoms to pollen-related food allergens in grass pollen-allergic patients from northern Europe.

BACKGROUND: Most studies on pollen-related food allergy have so far focused on the association of birch/weed pollen allergens and plant food allergy. The aim of this study was to elucidate the allergen spectrum among a group of grass pollen-allergic patients from northern Europe and to relate the results to clinical histories of pollen-related food allergy. METHODS: Fifty-eight grass pollen-allergic patients answered a questionnaire regarding allergy to foods. Blood samples were taken to test IgE-reactivity to a large panel of pollen allergens and pollen- and nonpollen-related food allergens using crude allergen extracts and recombinant and native allergens. RESULTS: Three different groups of grass pollen-allergic patients were identified according to their IgE antibody profile: a grass pollen group only (19%), a grass and tree pollen group (29%) and a grass, tree and compositae (pan-) pollen group (48%). No sensitization to Bet v 1 as well as almost no IgE to plant food was observed in the grass pollen group. In contrast, nearly all patients in the two tree-related groups had IgE to Bet v 1, which reflected the high frequency of adverse reactions to typical birch-related food in these groups. Only four patients belonging to the pan-pollen group displayed IgE to profilin Phl p 12/Bet v 2. Patients in the pan-pollen group reported significantly more symptoms to food allergens compared with patients in the two other groups. The most frequently reported symptom was the oral allergy syndrome. CONCLUSIONS: Sensitization to grass pollen alone is rare among grass pollen-allergic patients from northern Europe. The majority of patients are in addition sensitized to birch (Bet v 1), which seems to be closely related to their pollen-derived food allergy. The study highlights the advantage of using well-defined allergen molecules for the diagnosis of cross-reactivity between pollen and food allergens.

Specific immunoglobulin E antibodies to peanut over time in relation to peanut intake, symptoms and age.

The clinical outcome of peanut allergy and some factors associated with development of peanut allergy remain unsolved. It has not been clarified to what extent peanut intake affects immunoglobulin (IgE) antibody formation in peanut sensitized individuals. The aim of the study was to investigate the development of peanut hypersensitivity in children and adolescents with specific IgE antibodies to peanut, using questionnaires and current serum tests and comparing it to information obtained 5-6 yr earlier, to investigate how peanut intake during this period related to subject age, IgE antibody levels and symptoms and to investigate what information this patient group was given at the time of diagnosis regarding avoidance of peanut related food. All patients with detectable peanut-specific IgE antibodies investigated during 1994-1996 deriving from two allergy laboratories in the western region of Sweden were traced and reinvestigated (n=132). A total of 111 subjects (63 with peanut allergy and 48 peanut sensitized) participated in the questionnaire. Eighty-six of them consented to be enrolled in a further interview and renewed testing of specific IgE antibody to peanut 5 yr later. All tests were done using the Pharmacia CAP system. Increased IgE antibody levels during follow-up was related to age; subjects 0-6 yr at initial test occasion were more likely to have higher IgE antibody class than the older individuals (p=0.018). Exposure to peanut during the study, i.e. 5-6 yr since diagnosis, did not seem to affect the result. During the follow-up period, 29 out of 86 (34%) increased their IgE antibody class. At the second test occasion the remaining subjects had similar (28%) or lowered (38%) levels of IgE antibodies. Exposure to peanut during follow-up was more common in subjects with IgE antibody class 1-3 compared to subjects with high value (> 3) at the initial test (p=0.003). Reported symptoms during follow-up were also more common in subjects with initially high IgE antibody value. Individuals with initially high IgE antibodies to peanut had been given more information about peanut allergy and cross-reacting allergens than other individuals. The subjects over 6 yr of age showed a decrease in peanut-specific IgE class over a 5-yr period. Together with the literature, our result suggest that follow-up and renewed testing is recommended, since there may be a change in IgE antibody classes and clinical sensitivity over time. Even in Sweden, with a low consumption of peanuts, the youngest individuals with peanut sensitization experienced a similar course of events that has been reported in other countries.

Introduction of food during the infant's first year: a study with emphasis on introduction of gluten and of egg, fish and peanut in allergy-risk families.

AIM: The aim of the current study was to retrospectively examine introduction of food during the first year in a representative sample of Swedish children. A secondary aim was to study how parents with history of atopy introduced food to their infants. METHODS: Data derive from 467 infants who visited child health centres in three different counties in Sweden for health check-up at 12 mo of age. The parents were asked to fill in a questionnaire about breastfeeding and/or formula feeding, time of introduction of weaning food focusing on cow's milk, follow-on formula, porridge, fish and egg. Questions regarding hypersensitivity in the family, peanut consumption of mother as well as in the child, and questions about number of siblings, ethnic background and parental education were included. RESULTS: Compliance with suggested introduction of gluten-containing food was low; as many as 45% had avoided gluten until 6 mo of age, instead of introducing gluten between 4 and 6 mo. Only 33% of parents with stated family hypersensitivity avoided giving their child fish and 23% avoided egg during the first year, even though this recommendation was present at the time of the study. Almost 50% of all mothers had avoided peanuts during pregnancy even though there was no such advice. The avoidance of peanut was not connected to hypersensitivity in the family. CONCLUSION: These results suggest that time of introduction of gluten was not in accordance with the current recommendation. The results imply that there is a need to follow up if and how this feeding information is distributed to parents with infants and also to sharpen the information to the right target groups, otherwise implementation of preventive strategies will be less useful.