Nowak-Wegrzyn Anna H, Bencharitiwong Ramon, Schwarz John, David Gloria, Eggleston Peyton, Gergen Peter J, Liu Andrew H, Pongracic Jacqueline A, Sarpong Sampson, Sampson Hugh A
Division of Pediatric Allergy and Immunology, Mount Sinai School of Medicine, New York, NY 10029, USA.
J Allergy Clin Immunol. 2009 Apr;123(4):949-955.e1. doi: 10.1016/j.jaci.2009.01.070.
Cockroach is an important allergen in inner-city asthma. The diagnosis and treatment of cockroach allergy has been impeded by the lack of standardized cockroach extracts.
We investigated the utility of a mediator release assay based on rat basophil leukemia (RBL) cells for comparing the potency of German cockroach extracts.
RBL cells (line 2H3) transfected with human FcepsilonRI were passively sensitized with sera from subjects with cockroach allergy and stimulated with serial dilutions of 3 commercial cockroach extracts (1:10 weight/volume). In addition, the in-house prepared extract was tested in separate experiments with pooled sera that produced optimal performance in the RBL assay. N-hexosaminidase release (NHR) was used as a marker of RBL cell degranulation and was examined in relation to the intradermal skin test (ID(50)EAL) and serum cockroach-specific and total IgE levels.
The median cockroach-specific IgE concentration in 60 subjects was 0.72 kU(A)/L (interquartile range, 0.35-2.97 kU(A)/L); 19 sera (responders) produced a minimum 10% NHR to more than 1 extract. Responders had higher median cockroach-specific IgE (7.4 vs 1.0 kU(A)/L) and total IgE (429 vs 300 kU/L) levels than nonresponders. Ranking of extract potency was consistent between the mediator release assay and the ID(50)EAL. For the in-house prepared cockroach extract, the dose-response curves were shifted according to the concentration of the extract. NHR was reproducible between different experiments by using pooled sera.
The mediator release assay measures biologic potency and correlates with the ID(50)EAL. It should be further evaluated to determine whether it could be used to replace intradermal skin test titration for assessing the potency of cockroach extract.
蟑螂是城市哮喘中的一种重要变应原。由于缺乏标准化的蟑螂提取物，蟑螂过敏的诊断和治疗受到了阻碍。
我们研究了基于大鼠嗜碱性粒细胞白血病（RBL）细胞的介质释放试验在比较德国蟑螂提取物效价方面的实用性。
用蟑螂过敏患者的血清对转染了人FcepsilonRI的RBL细胞（2H3系）进行被动致敏，并用3种市售蟑螂提取物的系列稀释液（1:10重量/体积）进行刺激。此外，在单独的实验中，用在RBL试验中表现最佳的混合血清对自制提取物进行了测试。以N - 乙酰氨基葡萄糖苷酶释放（NHR）作为RBL细胞脱颗粒的标志物，并与皮内皮肤试验（ID(50)EAL）以及血清蟑螂特异性IgE和总IgE水平相关联进行检测。
60名受试者的蟑螂特异性IgE浓度中位数为0.72 kU(A)/L（四分位间距，0.35 - 2.97 kU(A)/L）；19份血清（反应者）对1种以上提取物产生至少10%的NHR。反应者的蟑螂特异性IgE中位数（7.4 vs 1.0 kU(A)/L）和总IgE中位数（429 vs 300 kU/L）高于无反应者。介质释放试验和ID(50)EAL之间提取物效价的排名是一致的。对于自制的蟑螂提取物，剂量 - 反应曲线根据提取物的浓度而移动。通过使用混合血清，不同实验之间的NHR具有可重复性。
介质释放试验可测量生物效价并与ID(50)EAL相关。应进一步评估其是否可用于替代皮内皮肤试验滴定以评估蟑螂提取物的效价。
