- 期刊
Whey and Casein Specific IgE and the Cow's Milk Challenge Test for Atopic Children
過敏兒乳清蛋白及酪蛋白特異性免疫球蛋白E之分析及牛奶激發試驗之反應
摘要
我們研究了30位病史高度懷疑對牛奶過敏，而確立診斷爲氣喘，異位性皮膚炎，及/或過敏性鼻炎的過敏孩童。年齡分佈由1歲4月至9歲6月，平均年齡5.03歲。這30位孩童皆先經由CAP系統分析篩選，確定對牛奶蛋白，都有二級驉之特異性免疫球蛋白E反應(大於0.7ku/l)。進一步分析發現，其中1位(3.3%)僅對α-乳白蛋白(α-lactoalbumin)的特異性免疫球蛋白E明顯昇高；只對β-乳球蛋白(β-lactoglobulin)特異性免疫球蛋白E明顯增加的有1位(3.3%)；同時對α-乳白蛋白及β-乳球蛋白之特異性免疫球蛋白E增加的有4位(13.9%)；有5位(16.7%)只對酪蛋白特異性免疫球蛋白E明顯增加；對酪蛋白及α-乳白蛋白特異性免疫球蛋白E增加的有8位(26.7%)；而同時對酪蛋白，α-乳白蛋白及β-乳球蛋白之特異性免疫球蛋白E增加的有11位(36.7%)。停止牛奶攝取3個禮拜之後，在門診進行牛奶激發試驗，結果我們所有的病人在門診觀察2個小時及回家3天的觀察中，都沒有出現包含皮膚，腸胃道及呼吸道之過敏反應。 研究的結果顯示：(1)牛奶蛋白過敏原中，乳清蛋白(尤其是α-乳白蛋白)及酪蛋白都佔有很高比例。(2)對牛奶蛋白産生特異性免疫球蛋白E的過敏兒，並不表示一定會對牛奶蛋白産生臨床上的過敏反應，確定牛奶蛋白是否會引起過敏反應，要經由牛奶激發試驗證實。
並列摘要
We studied 30 atopic children who suspected of milk allergy by past history (age ranging from 1 yr 4 mo to 9 yr 6 mo, mean age: 5.03 yr.) diagnosed as having asthma, atopic dermatitis and/or allergic rhinitis. These 30 atopic children had been screened from the patients at our outpatient clinic by the Pharmacia CAP system RAST FEJA. All of them showed the presence of at least Class II (greater than 0.7 ku/l) IgE specflc to proteins in cow’s milk. Further analysis found IgE specJIc to α-lactoalbumin (α-LA) elevated in 1 patient (3.3%), 1 patient (3.3%) to β-lactoglobulin (β-LG), 4 patients (13.3%) to α-LA and β-LG, 5 patients (16.7%) to casein, 8 patients (26.7%) to casein and α-LA, 11 patients (36.7%) to casein, α-LA and β-LG. After 3 weeks’ cow-milk-free diet, the patient’s milk challenge test was performed at our outpatient clinic. According to the test result, none of these 30 atopic children showed clinical evidence of signfIcant allergic reaction to cow’s milk in the skin, the gastrointestinal tract or the respiratory tract either within two hours after the challenge test or within 3 days after they went home. We therefore conclude that: (1) No single major allergen is apparent in cow’s milk: casein, α-LA and, β-LG all show a high proportion of positive reactions. (2) Many atopic children fully tolerate cow’s milk, although they have high titer of IgE antibodies specfic to cow’s milk. The RAST test is only the first step to screen patients with suspected IgE-mediated allergies. To make sure, any positive reaction must be confirmed by the “golden standard” for diagnosis, i.e., the double-blind placebo-controlled food challenge.