Muñoz Martín T, de la Hoz Caballer B, Marañón Lizana F, González Mendiola R, Prieto Montaño P, Sánchez Cano M
Allergy Service, Hospital Ramón y Cajal, Madrid, Spain.
Allergol Immunopathol (Madr). 2004 Jan-Feb;32(1):39-42. doi: 10.1016/s0301-0546(04)79222-8.
Cow's milk proteins are amongst the most common causes of food allergy in infants, and caseins are probably the main allergens. The existence of a high degree of cross-reactivity between milk caseins from different animals has been reported. We describe a 2-year-old boy who experienced allergic reactions after eating and touching sheep's cheese, but who tolerated cow's milk and cow's milk dairy products. He had never ingested milk or milk derivatives from sheep or goat.
Skin prick tests were carried out using whey fractions of cow's milk, whole milk and casein from goat, sheep and cow. We also performed skin prick tests with enzymes used in cheese production. Prick-by-prick tests with cheese made from cow, sheep and goat and their corresponding whole milk were also performed. Total serum IgE and specific IgE to cow's milk proteins, whole cow's milk and sheep's milk were determined. Specific IgE against casein and whole milk from the three different species were determined by ELISA. Inhibition of IgE binding to bovine casein was tested for casein and whole milk from all three species. The proteins of three types of casein and whole milk from cow, sheep and goat were separated by SDS-PAGE and were incubated with the patient's serum.
Skin tests were positive to sheep's milk and goat and sheep casein and were negative to all cow's milk proteins and whole cow's and goat's milk. Prick-by-prick tests were positive to goat's and sheep's cheese and were negative to cow's cheese. In ELISA-inhibition, sheep's milk and goat and sheep casein were able to inhibit > 50 % of specific IgE binding to sheep casein. The results of immunoblotting showed that the patient's circulating IgEs recognized only one band in the lanes corresponding to sheep and goat casein.
We report a patient with allergy to sheep's and goat's milk proteins but not to cow's milk proteins. Sheep casein was probably the main allergen causing sensitization in this patient. The results suggest that sheep casein shows a high degree of cross-reactivity with goat casein but not with cow casein. Our patient presented allergic symptoms caused by sheep and goat milk and cheese proteins. However, he was able to tolerate cow's milk and cow's milk dairy products without any ill effects.
牛奶蛋白是婴儿食物过敏最常见的原因之一，酪蛋白可能是主要过敏原。有报道称不同动物的牛奶酪蛋白之间存在高度交叉反应。我们描述了一名2岁男孩，他在食用和接触羊奶酪后出现过敏反应，但能耐受牛奶及牛奶制品。他从未摄入过来自绵羊或山羊的奶或奶制品。
使用牛奶乳清成分、全脂牛奶以及山羊、绵羊和牛的酪蛋白进行皮肤点刺试验。我们还用奶酪生产中使用的酶进行了皮肤点刺试验。对由牛、绵羊和山羊制成的奶酪及其相应的全脂牛奶进行逐点试验。测定了总血清IgE以及针对牛奶蛋白、全脂牛奶和羊奶的特异性IgE。通过酶联免疫吸附测定法（ELISA）测定针对三种不同物种的酪蛋白和全脂牛奶的特异性IgE。测试了所有三种物种的酪蛋白和全脂牛奶对IgE与牛酪蛋白结合的抑制作用。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分离牛、绵羊和山羊的三种酪蛋白及全脂牛奶的蛋白质，并与患者血清孵育。
皮肤试验对羊奶、山羊和绵羊酪蛋白呈阳性，对所有牛奶蛋白、全脂牛奶和山羊奶呈阴性。逐点试验对山羊奶酪和绵羊奶酪呈阳性，对牛奶酪呈阴性。在ELISA抑制试验中，羊奶、山羊和绵羊酪蛋白能够抑制>50%的特异性IgE与绵羊酪蛋白的结合。免疫印迹结果显示，患者循环中的IgE仅在对应绵羊和山羊酪蛋白的泳道中识别出一条带。
我们报告了一名对绵羊和山羊奶蛋白过敏但对牛奶蛋白不过敏的患者。绵羊酪蛋白可能是该患者致敏的主要过敏原。结果表明，绵羊酪蛋白与山羊酪蛋白显示出高度交叉反应，但与牛酪蛋白没有交叉反应。我们的患者出现了由绵羊和山羊奶及奶酪蛋白引起的过敏症状。然而，他能够耐受牛奶及牛奶制品，没有任何不良影响。
