Food-induced anaphylaxis

To date, there are no population-based epidemiologic studies providing information about the prevalence of food-induced anaphylaxis. However, statistics from the United Kingdom demonstrated an increase of anaphylaxis from 5.6 cases per 100000 hospital discharges in 1991–92 to 10.2 cases in 1994–95. The increase for the subcategory of food-induced anaphylaxis was above the overall increase in anaphylaxis. In the UK register of fatal anaphylactic reactions, all food-induced fatalities have been accompanied by respiratory problems with respiratory arrest. Atopic individuals with bronchial asthma and prior allergic reactions to the same food are at a particularly high risk. Not only peanuts, seafood and milk can induce severe, potentially lethal, anaphylaxis, but indeed a wide spectrum of foods, according to the different patterns of food sensitivity in different countries. Foods with "hidden" allergens and meals at restaurants are particularly dangerous for patients with food allergies. Similarly, schools, public places and restaurants are the major places of risk. However, the main factor contributing to a fatal outcome is the fact that the victims did not carry their emergency kit with adrenaline (epinephrine) with them. Therefore, we suggest that the pharmaceutical industry should reintroduce an adrenaline inhaler that is more effective, especially in asthmatic reactions.     

广州市越秀区2007-2008年食品中化学污染物检测结果分析

目的掌握广州市越秀区食品中化学污染物的现状。方法随机抽取越秀区内部分市场、超市及餐饮企业的各类食品开展金属及有害元素、甲醛、抗生素、农药、添加剂等30余项污染物的检测。结果2007-2008年的监测结果显示,铅含量平均合格率为95.28%,粮食和皮蛋合格率最低,为87.5%,水产品镉的合格率为85%;鸡蛋的土霉素检出率为66.67%,禽畜肉中四环素、土霉素和氯霉素检出率分别为27.27%、15.91%和4.55%;保鲜食品甲醛的检出率最高,达76.19%,水发食品中甲醛平均含量为538.64mg/kg,检出率为66.67%;水产中六六六的检出率为36.11%,其他食品中均未检出农药;乳制品中苯甲酸的超标率为28.57%;凉拌菜和熟肉中存在违规添加胭脂红、柠檬黄、日落黄的现象,熟肉中柠檬黄的超标率为7.84%。结论越秀区部分食品受到铅、甲醛、抗生素及添加剂的污染,存在食品安全的风险,应加大监督监测的力度。     

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

Background The clinical manifestations of cow's milk allergy (CMA) are highly variable, and challenges usually identify only immediate. IgE mediated reactions. Objective To clearly identify CMA of immediate and delayed types using a two-stage. double-blind, placebo-controlled food challenge (DBPCFC), and to prospectively compare the clinical history and analyses of specific IgE antibodies to milk in predicting outcome of DBPCFC. Methods A total of 69 patients (33 girls, 36 boys) were recruited for sludy based on a history highly suggestive of CMA and resolution of symptoms on a bovine protein-free diet. After skin-prick tests (SPTs) and search for allergen-specific serum IgE antibodies by enzyme allergosorbent test (EAST), a two-stage DBPCFC was performed over several days. Results Of 16 patients (mean age 36.9 months) classified as probable immediate reactors based on the history, 10 (62.5%) had a positive DBPCFC with similar patterns to historical adverse reactions (≥ 2 h after milk exposure). The other 53 (77%) patients (17.3 months) had a history of probable delayed type CMA presenting with predominantly gastrointestimal symptoms from 2h and up to 6 days after milk exposure. Of these. 15 (28.8%) had a positive DBPCFC. again with a symptom pattern similar to the history. Sensitivity/specificity of SPT was similar to that of EAST for both immediate (70/83% and 62/83% respectively. NS) or delayed (0/97% and 0/97%) CMA confirmed by DBPCFC. Conclusions Using our two-stage, prolonged DBPCFC, we clearly identified two groups of children with CMA, reflecting different pathogenesis of either immediatetype IgE-dependent, or delayed-type IgE-independent allergy. Although useful in immediate reactors. IgE antibody determination cannot predict the outcome of DBPCFC in delayed reactors. A thorough clinical history was the mo.st helpful tool to predict the type of response in challenge positive patients.     

IL-12 and IL-23 in health and disease

Food allergy affects up to 6% of children and 3–4% of adults in Westernized countries, and is the most common cause of outpatient anaphylaxis in most studies. The mainstay of treatment is strict avoidance of the offending allergens and education regarding the use of emergency medication in cases of accidental ingestions or exposures. While these approaches are generally effective, there are no definitive treatments that cure or provide long-term remission from food allergy. However, with recent advances in characterizing food allergens and understanding humoral and cellular immune responses in food allergy, several therapeutic strategies are being investigated. Potential treatments include allergen-specific immunotherapy as well as allergen-nonspecific approaches to downregulate the overall allergic response in food-allergic individuals.     

Prevalence and cumulative incidence of food hypersensitivity in the first 3 years of life

Background:  Prevalence and incidence of food hypersensitivity (FHS) and its trends in early childhood are unclear.
Methods:  A birth cohort born on the Isle of Wight (UK) between 2001 and 2002 was followed-up prospectively. Children were clinically examined and skin prick tested at set times and invited for food challenges when indicated.
Results:  Nine hundred and sixty-nine children were recruited and 92.9%, 88.5% and 91.9% of them respectively were assessed at 1, 2 and 3 years of age. Prevalence of sensitization to foods was 2.2%, 3.8% and 4.5% respectively at these ages. Cumulatively, 5.3% [95% confidence interval (CI): 3.9–7.1] children were sensitized to a food. Using open food challenge and a good clinical history, the cumulative incidence of FHS was 6.0% (58/969, 95% CI: 4.6–7.7). Based on double-blinded, placebo-controlled, food challenge (DBPCFC) and a good clinical history, the cumulative incidence was 5.0% (48/969, 95% CI: 3.7–6.5). There is no evidence to suggest that the incidence of FHS has increased, comparing these results with previous studies. Overall, 33.7% of parents reported a food-related problem and of these, 16.1% were diagnosed with FHS by open challenge and history and 12.9% by DBPCFC and history. Main foods implicated were milk, egg and peanut.
Conclusions:  By the age of 3 years, 5–6% of children suffer from FHS based on food challenges and a good clinical history. There were large discrepancies between reported and diagnosed FHS. Comparing our data with a study performed in the USA more than 20 years ago, there were no significant differences in the cumulative incidence of FHS.     

Natural history of IgE-dependent food allergy diagnosed in children during the first three years of life

PurposeThe aim of the study was to analyze: the course of allergy diagnosed during first three years of life, frequency of food tolerance development and impact of factors which have potential meaning in that process.Material and MethodsThe study was performed in 115 children with IgE-dependent allergy, diagnosed during first three years of life, treated in 2nd Department of Pediatrics and Allergology of Polish Mothers Health Center in Lodz. All children were invited to our clinic in order to analyze course of the allergy after period of minimum 5 years since diagnosis.ResultsThe results of the study revealed that food tolerance was acquired by high percentage of examined children (87.9%) among 83 children with food allergy. However among 32 children with initial inhalant allergy there were still no food sensitizations. The frequency of this process increased with age of examined children. The study revealed that such factors as lack of family history of atopy, clinical manifestation limited to one system, lack of inhalant allergy, type of allergen, good social conditions, have positive impact on tolerance development.ConclusionsHigh percentage of children with food allergy is able to develop the status of food immunotolerance. Factors which predispose to development of food allergy have also negative impact on ability to acquiring tolerance to harmful food. The study indicates the need of constant and wide education about decreasing exposure to allergy predisposing factors which could increase chance of food tolerance development.     

Standardization of double-blind, placebo-controlled food challenges

At present, no international agreement on standardized protocols for use in double-blind placebo-controlled food challenge exists. There is a great need for such standardization, both for clinical and for scientific reasons.     

Presentation of allergen in different food preparations affects the nature of the allergic reaction – a case series

BACKGROUND: Characterization of fatal and non-fatal reactions to food indicates that the majority of reactions are due to the ingestion of prepared foods rather than the non-processed allergen. In an ongoing study that used a double-blind placebo-controlled food challenge to investigate peanut allergy and clinical symptoms, the observed reaction severity in four of the first six subjects was greater than anticipated. We hypothesized that this was due to differences in the composition of the challenge vehicle. OBJECTIVE: The aim was to investigate whether the severity of observed challenge reactions would be repeated on re-challenge with a lower fat challenge vehicle. METHODS: Peanut-allergic subjects were re-challenged with a lower fat recipe after reacting more severely than was anticipated to an initial peanut challenge. Similar challenge vehicle recipes were used, the only difference being the lower fat content (22.9% compared with 31.5%). The peanut content of the two recipes was analysed using RAST inhibition studies and ELISA tests. RESULTS: Three of four subjects reacted to much smaller doses of peanut protein on re-challenge (mean dose equivalence - 23 times less peanut) with the lower fat recipe. RAST inhibition showed that neither recipe altered epitope recognition. The higher fat recipe required twice as much peanut to cause 50% inhibition. ELISA detected far lower levels of peanut in the higher fat recipe (220 000 parts per million (p.p.m.)) than in the lower fat recipe (990 000 p.p.m.). CONCLUSION: The fat content of a challenge vehicle has a profound effect on the reaction experienced after allergen ingestion. This is another factor to be considered in assessing the risk of certain foods to food-allergic consumers and adds another dimension to clinical, research and regulatory practice.     

Confirmed prevalence of food allergy and non-allergic food hypersensitivity in a Mediterranean population

Background Until the present, no comprehensive studies evaluating the prevalence of food allergy and non‐allergic food hypersensitivity (FA/NAFH) in adults have been done in Turkey or its surrounding countries. Objective This large population‐based study was planned to identify the confirmed prevalence of adverse reactions to food in adults in Istanbul. Methods A total of 17 064 telephone numbers were randomly selected from both the European and Asian sides of Istanbul, and the 11 816 subjects who agreed to participate in the study were addressed with a questionnaire of eight items. Those who disclosed food‐related complaints in this survey were called again and a similar questionnaire was repeated. The respondents who were suspected of having food allergy or food hypersensitivity were invited for a personal clinical investigation that included double‐blind, placebo‐controlled food challenge tests. Results The lifetime prevalence of self‐reported FA/NAFH was found to be 9.5% [1118/11 816; 95% confidence interval (CI): 8.94–10.00%]. After the clinical investigations, the point prevalence of FA/NAFH, which also included the ‘possible FA/NAFH group’, was found to be as low as 0.3% (30/11 816; 95% CI: 0.17–0.36%), and the FA/NAFH rates assessed by double‐blind, placebo‐controlled food challenge tests were 0.1% (12/11 816; 95% CI: 0.05–0.18%) and 0.1% (11/11 816; 95% CI: 0.05–0.17%), respectively. The most significant factor influencing FA/NAFH was familial atopy (adjusted OR 4.3; 95% CI: 3.67–4.99), and the most related atopic disease was itching dermatitis/urticaria (adjusted OR: 3.9; 95% CI: 3.31–4.54). Conclusion We may conclude that FA/NAFH in the Turkish population seems to be low when compared with Northern and Western European countries. This may be due to genetic, cultural or dietary factors, and further studies evaluating the reasons for this low prevalence of FA/NAFH in our population are needed.     

How to make foods safer – genetically modified foods

It is the responsibility of companies developing genetically modified foods, and of regulatory authorities that approve their marketing, to ensure that they are at least as safe as the traditional foods they are intended to replace in the diet. This requires that any novel material introduced into the food material should not be allergenic. If the novel gene has come from an allergenic source, e.g. nuts, it is necessary to demonstrate using immunological procedures applied to the IgE fractions of pooled sera from individuals with confirmed allergies that the novel protein is non-allergenic. When the novel gene is from a non-allergenic source then it is necessary to demonstrate lack of significant amino acid sequence homology to known allergens together with sensitivity to food manufacturing and digestive processes. Consumer confidence in genetically modified foods would be significantly improved if hypoallergenic varieties of crops and food products that are currently allergenic could be developed. Techniques such as antisense technology and single site amino acid substitution have been shown to have such potential.     

Cytodestructive Mechanisms Provoked by Food Antigens

Antibody-dependent, allergic autocytotoxicity (ACT) is an in vitro process through which WBC from patients and/or controls, passively sensitized with RAST positive serum, are damaged in the presence of corresponding food antigens. Studies among 13 patients, sensitive to cow milk, corn and wheat, and 13 asymptomatic controls revealed that antibody-dependent ACT is mediated by thermolabile cytotoxic factor, presumably IgE antibody. The resultant cellular interactions might contribute to the induction of the autoimmune response.     

广州市超市自制食品卫生状况调查与分析

目的了解目前广州市不同规模超市自制食品的卫生状况。方法采用分层抽样的方法，抽取大型超市18间、中型超市4间、小型超市14间作为调查对象。采用现场监督检查、询问和填写调查表的方法进行调查。结果对不同规模超市生熟交叉污染、预进间的设置、空气消毒设备和空调设置等方面进行了比较，大型、中型超市成品区域的设施方面都比小型超市成品区域设施规范，差异均有统计学意义（P〈0．05）。超市中自制食品存在安全隐患，尤以小型超市为甚。结论应重点加强对小型超市自制食品卫生状况的监管。     

一起外运快餐引起爆发性食物中毒的调查报告

目的查明一起集体食物中毒事件发生的原因及影响因素。方法对食用该可疑食品的人员进行个案调查．对部分患者、从业人员肛拭采样以及抽检可疑食物、餐具进行细菌培养。结果共调查了539人，其中263人出现胃肠道症状，感染率为48．79％，确诊病例为82例。发病高峰集中在11月1日0-12时；临床症状以腹痛、腹泻为主。9例患者肛拭培养中检出致病性大肠埃希菌O127或腊样芽孢杆菌，1份卤水和4份餐具样品中亦检出致病菌。结论该起食物中毒是由混合性致病菌引起的，食品被污染的环节复杂多样。