原標(biāo)題：非洲特應(yīng)性皮炎兒童雞蛋敏感、過敏與組份模式
　　雞蛋是兒童過敏性皮炎(AD)最常見的食物。本研究旨在確定南非AD患兒雞蛋過敏的患病率、組份模式及篩查試驗(yàn)的預(yù)測(cè)值。這是在開普敦一所兒科大學(xué)醫(yī)院進(jìn)行的一項(xiàng)前瞻性觀察研究。隨機(jī)招募6個(gè)月到10歲的AD患兒。通過問卷調(diào)查、皮膚點(diǎn)刺(SPT)、免疫固相過敏原芯片(ISAC 103®)檢測(cè)、對(duì)雞蛋和卵類粘蛋白（Gal d 1）的ImmunoCAP組份測(cè)試和附加食物激發(fā)試驗(yàn)評(píng)估他們對(duì)雞蛋的敏感性和過敏情況。100位參與者（59非洲黑人和41混合族群），平均年齡42月。有高達(dá)54%的雞蛋敏感率和25%的雞蛋過敏發(fā)病率。病史和實(shí)驗(yàn)室篩查試驗(yàn)對(duì)雞蛋過敏發(fā)病率的估計(jì)明顯過高。在診斷雞蛋過敏中，新鮮雞蛋白皮膚點(diǎn)刺試驗(yàn)比商用雞蛋白提取物皮膚點(diǎn)刺試驗(yàn)更為敏感，并且其產(chǎn)生的ROC曲線下面積在所有的預(yù)測(cè)真正雞蛋過敏的篩查試驗(yàn)中最大。在那些對(duì)雞蛋敏感的受試者中，卵類粘蛋白組份是區(qū)分雞蛋過敏和耐受的最佳組份。雞蛋SPT和雞蛋白ImmunoCAP通常用的95%陽(yáng)性預(yù)測(cè)值在該人群的總的陽(yáng)性預(yù)測(cè)值分別57%和74%，在黑人中預(yù)測(cè)值通常比混合人種要低。該人群中，以對(duì)鮮雞蛋的皮膚點(diǎn)刺值17mm和雞蛋白ImmunoCAP值13 kU/l作為標(biāo)準(zhǔn)判斷雞蛋過敏有最好的陽(yáng)性預(yù)測(cè)值。
　　非洲特應(yīng)性皮炎兒童中雞蛋過敏的發(fā)病率高，但是，真正的雞蛋過敏率明顯比雞蛋過敏病史和對(duì)雞蛋的敏感性所估計(jì)的要低。對(duì)鮮雞蛋白的皮膚點(diǎn)刺試驗(yàn)比商用的雞蛋白提取液更為敏感，因此，鮮雞蛋白應(yīng)該推薦進(jìn)入雞蛋過敏篩檢項(xiàng)目中。卵類粘蛋白組份在對(duì)雞蛋敏感的受試者中區(qū)分雞蛋過敏和耐受上有重要作用。有必要在發(fā)展中國(guó)家建立人群特異性的雞蛋過敏檢測(cè)的95%陽(yáng)性預(yù)測(cè)值。
　　延伸閱讀


Allergy                                                  
Egg sensitization, allergy and component patterns in African children with atopic dermatitis
https://doi.org/10.1111/pai.12615
Abstract:
Background
Egg allergy is the most common food allergy in children with atopic dermatitis (AD). This study aimed to determine the prevalence of egg allergy, component patterns and predictive values of screening tests in egg allergy in South African children with AD.
Methodology
This was a prospective, observational study in a paediatric university hospital in Cape Town. Children with AD, aged 6 months to 10 years, were recruited randomly. They were assessed for sensitization and allergy to egg by questionnaire, skin prick tests (SPT), Immuno Solid Phase Allergen Chip (ISAC 103®) test, ImmunoCAP component tests to egg and ovomucoid (Gal d 1) and incremental food challenges.
Results
Hundred participants (59 Black Africans and 41 of mixed ethnicity) were enrolled, median age 42 months. There was a high rate of egg sensitization of 54% and prevalence of confirmed egg allergy of 25%. History and screening laboratory tests overestimated egg allergy significantly. SPT to fresh egg white was significantly more sensitive in diagnosing egg allergy than SPT to the commercial egg white extract and produced the highest area under the receiver operator characteristics curve of all the screening tests in predicting true egg allergy. In those participants sensitized to egg, the component ovomucoid was best at differentiating true egg allergy from tolerance. Commonly used 95% positive predictive values (PPVs) for SPT to egg and ImmunoCAP egg white produced low PPV of 57% and 74%, respectively, in this population overall, with generally poorer predictive values amongst the Black Africans than the mixed ethnicity participants. A SPT to fresh egg of 17 mm and ImmunoCAP egg white of 13 kU/l produced the best PPV for egg allergy in this population.
Conclusion
The prevalence of egg allergy is high in African children with AD, but history of egg allergy and sensitization to egg significantly overestimate the true egg allergy rate. SPT to fresh egg white was more sensitive than that to commercial egg white extract; hence, fresh egg white should be recommended in an egg allergy screening panel. The component ovomucoid was useful for differentiating allergy from tolerance in egg‐sensitized participants. Population‐specific 95% PPV for egg allergy tests may need to be established in developing world populations.
All Authors:
Claudia L. Gray  Michael E. Levin George du ToitKing's Health Partners, MRM & Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, UKDepartment of Paediatric Allergy, Guy's and St Thomas' NHS Foundation Trust, London, UK
　　創(chuàng)建過敏性疾病的科研、科普知識(shí)交流平臺(tái)，為過敏患者提供專業(yè)診斷、治療、預(yù)防的共享平臺(tái)。