Division of Pediatric Allergy & Immunology, The Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
Clin Exp Allergy. 2012 Feb;42(2):238-47. doi: 10.1111/j.1365-2222.2011.03864.x. Epub 2011 Sep 21.
Occasionally, exclusively breastfed infants with cow's milk allergy (CMA) remain symptomatic despite strict maternal milk avoidance.
To determine whether or not persistence of symptoms could be due to sensitization against endogenous human milk proteins with a high degree of similarity to bovine allergens.
Ten peptides representing known bovine milk IgE-binding epitopes [α-lactalbumin (ALA), β- and κ-casein] and the corresponding, highly homologous human milk peptides were labelled with sera from 15 breastfed infants with CMA, aged 3 weeks to 12 months, and peptide (epitope)-specific IgE antibodies were assessed. Nine of the 15 breastfed infants became asymptomatic during strict maternal avoidance of milk and other major food allergens; six infants remained symptomatic until weaned. Ten older children, aged 5-15 years, with CMA were also assessed. The functional capacity of specific IgE antibodies was assessed by measuring β-hexosaminidase release from rat basophilic leukaemia cells passively sensitized and stimulated with human and bovine ALA.
A minimum of one human milk peptide was recognized by IgE antibodies from 9 of 15 (60%) milk-allergic infants, and the majority of older children with CMA. Genuine sensitization to human milk peptides in the absence of IgE to bovine milk was occasionally seen. There was a trend towards specific IgE being detected to more human milk peptides in those infants who did not respond to the maternal milk elimination diet than in those who did (P = 0.099). Functional IgE antibody to human ALA was only detected in infants not responding to the maternal diet.
Endogenous human milk epitopes are recognized by specific IgE from the majority of infants and children with CMA. Such autoreactive, human milk-specific IgE antibodies appear to have functional properties in vitro. Their role in provoking allergic symptoms in infants exclusively breastfed by mothers strictly avoiding dietary milk remains unclear.
尽管严格避免母亲的牛奶和其他主要食物过敏原，但一些患有牛乳过敏（CMA）的纯母乳喂养婴儿仍然存在症状。
确定症状持续存在是否可能是由于对与人乳过敏原具有高度相似性的内源性人乳蛋白产生致敏作用所致。
用 15 名患有 CMA 的母乳喂养婴儿（年龄 3 周至 12 个月）的血清标记 10 个代表已知牛乳 IgE 结合表位的肽[α-乳白蛋白（ALA），β-和κ-酪蛋白]和相应的高度同源人乳肽，并评估肽（表位）特异性 IgE 抗体。在严格避免牛奶和其他主要食物过敏原的情况下，15 名母乳喂养婴儿中有 9 名变得无症状；6 名婴儿直到断奶仍有症状。还评估了 10 名年龄在 5-15 岁的患有 CMA 的大龄儿童。通过测量被动致敏和用人类和牛 ALA 刺激的大鼠嗜碱性白血病细胞中β-己糖胺酶的释放来评估特异性 IgE 抗体的功能能力。
在 15 名（60％）牛奶过敏婴儿中，有 9 名（60％）的 IgE 抗体至少能识别一种人乳肽，并且大多数患有 CMA 的大龄儿童也能识别。在没有对牛乳的 IgE 反应的情况下，偶尔会出现对人乳肽的真正致敏。在未对母亲的饮食消除饮食产生反应的婴儿中，与对其产生反应的婴儿相比，检测到更多的人乳肽特异性 IgE 的趋势（P=0.099）。仅在未对母亲饮食产生反应的婴儿中检测到针对人 ALA 的功能性 IgE 抗体。
大多数患有 CMA 的婴儿和儿童的特异性 IgE 可识别内源性人乳表位。这种自身反应性，人乳特异性 IgE 抗体在体外具有功能特性。它们在引起严格避免饮食中牛奶的纯母乳喂养婴儿的过敏症状中的作用尚不清楚。
