脐血IgE值用于预报食物过敏高危儿童的研究

目的　探讨脐血IgE用于预报食物过敏 (FA)高危儿童的可行性及影响因素 ,为早期预防提供线索。方法　随机选取 2 0 0 1年 4～ 7月出生的婴儿 118人 ,随访至生后 4个月 ,资料完整者10 5人。诊断及分组采用标准问卷调查和食物皮肤点刺试验 ,应用纸片放射免疫吸附法测定脐血IgE值。结果　 4个月时 ,经确诊为食物过敏患儿组的脐血IgE值高于未发生食物过敏的婴儿组及不能确诊为食物过敏的婴儿组 (P <0 0 5 ) ;当脐血IgE值的预报界值定为 0 9IU/L(CBIgE0 9)或 0 5IU/L(CBIgE0 5)时 ,高脐血组FA检出率高于低脐血组 (P <0 0 1) ,提示脐血IgE升高是导致食物过敏的危险因素之一 ;CBIgE0 9预报食物过敏的准确性优于CBIgE0 5(P <0 0 1) ;婴儿生后过早接触香烟、动物皮屑、过早添加鸡蛋均是影响脐血IgE值预报食物过敏准确性的危险因素 (P <0 0 1)。 结论　高脐血IgE值是食物过敏的高危因素 ,对食物过敏高危儿童有预报作用 ;CBIgE0 9进行预报的准确性高于CBIgE0 5;某些婴儿生后的环境因素如过早接触香烟、动物皮屑 ,过早添加鸡蛋等可影响脐血IgE值预报的准确性。

Prediction of food allergy by using cord blood IgE levels

OBJECTIVE: As more attention is paid to food allergy which is already regarded as a public health problem, there is still a lot of uncertainty as to the mechanisms and there are limited therapeutic methods for this problem. It is of importance to screen the susceptible infants as early as possible. The present study was conducted to learn whether cord blood IgE levels (CBIgE) could be used as a predictor of food allergy, and to find out factors which influence the predictive accuracy of CBIgE. METHODS: The present study enrolled 118 infants born between April 2001and July 2001, and the authors followed up the infants until they were 4 months old. At the end of follow up, 105 infants had complete data for evaluation. Paper radioimmunosorbent tests (PRIST) were used for CBIgE assay, and parents were required to answer the standard questionnaires and the food skin prick tests (SPT) were taken for all infants. RESULTS: At the end of follow-up, the infants were divided into 3 groups based on food allergy status: FA group with obvious food allergy, SFA group with suspected food allergy and NFA group without allergy. The median values of CBIgE levels in FA group were higher than those in SFA and NFA groups (4.80 IU/L, 0.55 IU/L, 0.87 IU/L, P < 0.01). When the cutoff value for CBIgE was set at 0.9 IU/L (CBIgE(0.9)), 42.9% of infants were found to have food allergy in the higher CBIgE group, 6.7% in the lower CBIgE group (P < 0.01, RR 95% CI = 2.715 approximately 15.221); when the cutoff value was set at 0.5 IU/L (CBIgE(0.5)), 30.9% in the higher CBIgE group and 5.00% in the lower CBIgE group (P < 0.01, RR 95% CI = 1.954 approximately 19.552). In addition, the sensitivity of CBIgE(0.9).as a predictor of food allergy, was 78.95% and the specificity, efficiency and odd product were 73.68%, 74.74%, and 10.50, generally better than CBIgE(0.5) of which the sensitivity, specificity, efficiency, odd product were 89.47%, 5.00%, 57.89%, 8.5 (P < 0.01). With the multi-factor stepwise regression analysis, our study indicated that exposure to cigarette smoke (OR 95%CI = 4.3340 approximately 71.2432), animal fur (OR 95% CI = 1.9869 approximately 30.7472), and egg supplement (OR 95% CI = 1.9340 approximately 25.8885) before 4 months of age might be the risk factors which may result in the predictive uncertainty of CBIgE. CONCLUSIONS: Increased CBIgE levels might be the risk factor which result in food allergy; CBIgE(0.9), as a predictor of food allergy, is superior to CBIgE(0.5). However, some environmental factors, such as early exposure to cigarette smoke, animal fur and too early egg supplement would lead to predictive uncertainty of CBIgE.