Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
Allergy and Immunology Group, Research Institute of Medical Science, Medical Education Plan and Promotion Room, Nihon University School of Medicine, Tokyo, Japan.
Allergol Int. 2014 May;63 Suppl 1:37-47. doi: 10.2332/allergolint.13-OA-0643.
Omalizumab, a monoclonal anti-IgE antibody, is currently indicated for the treatment of moderate-to-severe allergic asthma. To measure active IgE levels in sera from patients treated with omalizumab, the IgE subfraction in complex with omalizumab should be eliminated from total IgE, and free IgE levels can then be determined. With the aim of therapeutic monitoring for anti-IgE therapy, we developed a new ELISA for free IgE.
We used recombinant human soluble FcεRIα as a capture antigen and a biotinylated polyclonal anti-IgE antibody for detection. Using the newly developed ELISA, we measured the serum free IgE levels weekly in four asthmatic patients after their first omalizumab injection. We also measured the serum free IgE levels in 54 patients treated with omalizumab for over 4 weeks.
This assay was technically robust, the mean recovery rate in serum was 93.16% ± 5.34%. For all patients, omalizumab treatment significantly reduced serum free IgE levels prior to the second omalizumab injection. To maintain the benefit of omalizumab, serum free IgE concentrations should be <50 ng/ml. However, in 14 of 54 patients treated with omalizumab for over 4 weeks, serum free IgE concentrations measured by our ELISA were >50 ng/ml.
Our data suggest that the measurement of free IgE levels using our newly developed ELISA would be useful for monitoring serum free IgE levels during omalizumab therapy.
奥马珠单抗是一种单克隆抗 IgE 抗体，目前被批准用于治疗中重度过敏性哮喘。为了测量接受奥马珠单抗治疗的患者血清中的活性 IgE 水平，应从总 IgE 中消除与奥马珠单抗结合的 IgE 亚类，然后可以确定游离 IgE 水平。为了进行抗 IgE 治疗的治疗监测，我们开发了一种新的游离 IgE ELISA。
我们使用重组人可溶性 FcεRIα作为捕获抗原，并用生物素化多克隆抗 IgE 抗体进行检测。使用新开发的 ELISA，我们在四名哮喘患者首次接受奥马珠单抗注射后每周测量一次血清游离 IgE 水平。我们还测量了 54 名接受奥马珠单抗治疗超过 4 周的患者的血清游离 IgE 水平。
该测定法技术稳健，血清中的平均回收率为 93.16%±5.34%。对于所有患者，奥马珠单抗治疗在第二次奥马珠单抗注射前显著降低了血清游离 IgE 水平。为了保持奥马珠单抗的疗效，血清游离 IgE 浓度应<50ng/ml。然而，在 54 名接受奥马珠单抗治疗超过 4 周的患者中，有 14 名患者的血清游离 IgE 浓度用我们的 ELISA 测量>50ng/ml。
我们的数据表明，使用我们新开发的 ELISA 测量游离 IgE 水平将有助于监测奥马珠单抗治疗期间的血清游离 IgE 水平。
