特应性皮炎婴幼儿IgE介导食物过敏的随访研究

目的探讨IgE介导的食物过敏在特应性皮炎中的作用及其转归。方法对86例深圳地区特应性皮炎患儿进行混合食物组过敏原筛查(fx5E)检测,阳性者进一步检测6种常见食物(鸡蛋白、牛奶、鱼、小麦、花生、大豆)过敏原特异性IgE(sIgE)。对sIgE阳性患儿建议采取过敏食物回避措施,随访6个月和2年。结果 86例患儿中,36例(42%)有IgE介导的食物过敏,牛奶和(或)鸡蛋白为主要过敏原,分别占70%和64%。31例患儿完成了2年随访,食物sIgE检测为1级的13例患儿目前均无过敏症状;13例2级患儿再次进食过敏食物,仍有5例出现症状;7例3级以上过敏患儿,目前再次进食过敏食物,均出现症状。结论 IgE介导的食物过敏是引起婴幼儿特应性皮炎的重要原因,牛奶和(或)鸡蛋白是主要的过敏食物。回避过敏食物可以明显缓解症状,轻度过敏者症状随年龄增长可以消失,过敏程度越高,再次接触过敏食物出现症状的可能性越大。     

Helicobacter pylori seropositivity in children with atopic dermatitis as sole manifestation of food allergy

A positive association between Helicobacter pylori antibodies and food allergy presenting with gastrointestinal symptoms has recently been reported. A subset of a H. pylori strain possesses an antigen, CagA, as a virulence factor. Anti‐ H. pylori and anti‐CagA IgG titre have been determined in children with atopic dermatitis (AD) as the sole clinical manifestation of food allergy. In this study, thirty patients with AD as the sole clinical manifestation of food allergy were examined (group A). For comparative purposes, 30 patients affected by food allergy with gastrointestinal symptoms (group B) and 30 affected by atopic asthma (group C) were studied. Anti‐ H. pylori and anti‐CagA immunoglobulin G (IgG) were determined in all individuals by means of the enzyme‐linked immunosorbent assay. The anti‐ H. pylori IgG titre was significantly higher in group A and group B vs. group C (p < 0.05); no significant difference was detected between group A and group B (p > 0.05). No significant difference in anti‐CagA titre was found between the groups. These data demonstrate a positive association between H. pylori antibodies and AD as the sole manifestation of food allergy. Further investigations are needed to evaluate the cause–effect relationship between H. pylori seropositivity and AD.     

Allergic status of schoolchildren with food allergy to eggs, milk or wheat in infancy

Although children allergic to eggs, milk or wheat in infancy tend to become tolerant by school age, the allergic status of these children at school age has not been well evaluated. To investigate the allergic status of schoolchildren who avoided eggs, milk or wheat because of an immediate-type allergic reaction at <1-yr-old (food avoiders in infancy), we conducted a large-scale questionnaire-based survey of schoolchildren. A questionnaire on allergic diseases was distributed to the parents of 14,669 schoolchildren aged 7 to 15 yr in 30 schools in Kyoto, Japan. Of these, 13,215 responded (response rate, 90.1%). The rate of 7-yr-old children who were food avoiders in infancy was 5.4%. This rate decreased as the current age of the children increased, down to 3% in 15-yr-old children, indicating that food allergy in infancy tended to become more prevalent over the past 8 yr. Although more than 80% became tolerant to these foods by school age, the prevalence of bronchial asthma, atopic dermatitis, allergic rhinitis and allergic conjunctivitis were significantly higher in this group. Moreover, avoidance of other foods (buckwheat, shellfish, fruits and others) at school age was seen at much higher frequencies than in non-food avoiders in infancy (adjusted odds ratio, 7.7; confidence interval, 5.9–10.2). This risk did not differ significantly between those who did and did not develop tolerance to eggs, milk and wheat by 3 yr old. In conclusion, food avoiders in infancy appear to have a higher risk of not only other allergic diseases ('atopic march') but also allergy to other foods ('food allergen march') at school age, indicating the need for continuous attention to food allergy.     

Is caesarean delivery associated with sensitization to food allergens and IgE-mediated food allergy: A systematic review

Several studies have shown differences in the composition of the gastrointestinal flora of children who develop sensitization to food allergens compared with non-allergic children. It has been hypothesized that changes in the gut microbiota resulting from caesarean section delivery could increase a child’s risk of developing food allergy; however, studies examining the relationship between mode of delivery and food allergy have produced conflicting results. The objective of this review was to determine whether there is sufficient evidence to support an association between delivery by caesarean section and the development of sensitization to food allergens and immunoglobulin E (IgE) mediated food allergy. Using predefined inclusion and exclusion criteria, MEDLINE and PubMed were searched for studies investigating the relationship between caesarean section delivery and food allergy. The information on the quality of the studies and results were extracted and analysed systematically. The search identified four relevant studies as per our protocol. Symptomatic food allergy was used as the outcome in two studies and was found to occur more frequently in children born by caesarean section in one study while the second study found no association between food allergy diagnoses and mode of delivery. The other two studies measured levels of food antigen-specific IgE, with both studies showing an increase in sensitization to food allergens among children born by caesarean section. Overall, there is evidence that the risk of developing IgE-mediated sensitization to food allergens is increased among children delivered by caesarean section, however further studies using objectively diagnosed food allergy as the outcome are needed to verify whether this equates to an increase in confirmed food allergy. Future birth cohort studies should control for the effects of mode of delivery when investigating environmental modifiers of food allergy.     

Household animal ownership is associated with infant animal source food consumption in Bangladesh

Context-specific research is needed on the relationship between household animal production and nutrition outcomes to inform programmes intervening in small-scale animal production. We examined associations between household animal/fishpond ownership and animal source food (ASF) consumption among 6- to 12-month-old infants enroled in the control arm of a cluster-randomised controlled trial in rural Bangladesh. We measured ASF consumption using a 7-day food frequency questionnaire at 6, 9 and 12 months and assessed household animal/fishpond ownership at 12 months. We developed negative binomial regression models with random intercepts for infant and cluster, controlling for infant age and sex, maternal age, socioeconomic status and season. Models were stratified by a dichotomised maternal decision-making score. Compared with infants in households without each animal type, those with 4–10 and ≥11 poultry consumed eggs 1.3 (95% confidence interval [CI]: 1.1, 1.6) and 1.6 (95% CI: 1.3, 2.0) times more, respectively; 2–3 and ≥4 dairy-producing animals consumed dairy 1.9 (95% CI: 1.3, 2.7) and 2.0 (95% CI: 1.3, 3.1) times more, respectively; and ≥12 meat-producing animals consumed meat 1.4 (95% CI: 1.0, 1.8) times more. It was unclear whether there was an association between fishpond ownership and fish consumption. Our results did not suggest that maternal decision-making power was a modifier in the relationship between animal/fishpond ownership and ASF consumption. In this South Asian context, strategies intervening in household animal production may increase infant consumption of eggs, dairy and meat, but not necessarily fish. Research is needed on the role of market access and other dimensions of women's empowerment.     

白细胞介素10受体1在食物过敏儿童外周血T淋巴细胞中的表达

目的　研究白细胞介素10受体1（IL-10R1）在食物过敏儿童外周血T淋巴细胞的表达及其临床意义。方法　选择2017-07-01至2017-12-31在北京大学第三医院儿科食物过敏门诊诊断为食物过敏的50例患儿作为食物过敏组,选择同期在北京大学第三医院儿童健康发展中心行健康体检的25名儿童作为对照组。采用流式细胞技术检测IL-10R1在两组儿童外周血CD4+T及CD8+T淋巴细胞表达阳性率及平均荧光强度值（MFI）。同时比较IL-10R1在过敏原特异性IgE阳性与阴性食物过敏患儿外周血CD4+T及CD8+T淋巴细胞表达阳性率及MFI。根据食物过敏患儿症状、体征严重程度进行赋值评分,分析食物过敏患儿IL-10R1在外周血CD4+T及CD8+T淋巴细胞表达阳性率与食物过敏症状、体征评分有无相关性。结果　IL-10R1在食物过敏组患儿外周血CD4+T及 CD8+T淋巴细胞表达阳性率和MFI均低于对照组,IL-10R1在食物过敏组CD4+T淋巴细胞表达阳性率和MFI中位数分别为40.23、 12.18; 在对照组CD4+T淋巴细胞表达阳性率和MFI中位数分别为45.32、 17.69（Z值分别为-2.506、 -5.457;P值分别为0.012、 0.000）。IL-10R1在食物过敏组CD8+T淋巴细胞表达阳性率和MFI中位数分别为34.50、 12.47;对照组CD8+T淋巴细胞IL-10R1表达阳性率和MFI中位数分别为39.46、 17.28（Z值分别为-4.035、 -5.226; P值分别为0.000、 0.000）。IL-10R1在过敏原特异性IgE阳性与阴性患儿外周血CD4+T及CD8+T淋巴细胞表达阳性率及MFI没有差异。食物过敏患儿IL-10R1在外周血CD4+T及CD8+T淋巴细胞表达阳性率与食物过敏症状、体征评分无相关性。结论　IL-10R1在外周血CD4+T淋巴细胞和CD8+T淋巴细胞表面表达减少可能与食物过敏发病有关;IL-10R1在外周血CD4+T淋巴细胞和CD8+T淋巴细胞表面表达在IgE和非IgE介导的食物过敏发病过程中均起作用;IL-10R1在外周血CD4+T淋巴细胞和CD8+T淋巴细胞表面表达可能与食物过敏发病严重程度无关。     

Proposal for a standardized interpretation of the atopy patch test in children with atopic dermatitis and suspected food allergy

The interpretation of the atopy patch test (APT) to foods is not standardized. This study aimed to validate the reading of the APT in terms of the diagnostic accuracy of individual skin signs. Eighty-seven children (mean age 2.4 +/- 2.5 yr, range 0.5-13.5; 57 male) with atopic dermatitis (AD) and suspected food allergies underwent APT to cow's milk, hen's egg, wheat and soy. Twelve-millimetre Finn chambers were applied for 48 h, and results were read after 48 and 72 h. Skin changes were graded for erythema, induration, papule formation and 'crescendo' phenomenon (increase of skin sign severity from 48 to 72 h). Food allergy was assessed by double blind, placebo-controlled food challenges (DBPCFC). Sensitivity, specificity and predictive values were calculated for each skin signs in relation to challenge outcome. Of 165 DBPCFC children, 75 (45%) were positive. The combination of any skin induration plus papules (seven or more), or of moderate erythema plus any induration plus seven or more papules had a positive predictive value (PPV) and specificity for the challenge outcome of 100%; however, the sensitivity was low (8% and 15%). The best diagnostic accuracy for single signs was found for induration beyond the Finn chamber margin (PPV 88%, specificity 99%, sensitivity 9%) and presence of at least seven papules (PPV 80%, specificity 96% sensitivity 21%). Presence of both induration and of at least seven papules at 72 h were the APT skin signs with the greatest diagnostic accuracy for food allergy in children with AD.