For all patients, demographic characteristics, severe asthma-related comorbidities (allergic rhinitis, chronic rhinosinusitis, and gastroesophageal reflux disease), asthma control test (ACT), asthma exacerbation that required at least three days of systemic corticosteroids, asthma treatment, fractional exhaled nitric oxide (FeNO) levels, pulmonary function (forced vital capacity, FEV
1), and blood test (eosinophil proportion, serum total IgE, and serum aeroallergen-specific IgE (ImmunoCAP
® total IgE and ImmunoCAP
® specific IgE, Phadia K.K., Tokyo, Japan)) results before and 52 weeks after omalizumab administration were extracted by reviewing medical records. Patients with allergic rhinitis were diagnosed by an otolaryngologist (M.S.) or pulmonologists (T.T., T.K., Y.K., M.T., K.Y., and A.N.) according to the guideline.19 (
link) Pretreatment serum aeroallergen-specific IgEs were classified into the following five groups:20 (
link) house dust; dust mite (
Dermatophagoides); mold (mixed molds [
Penicillium, Cladosporium, Aspergillus, Candida, and
Alternaria] and
Trichophyton); animal dander (cat dander, dog dander); pollen (Japanese cedar, mixed grass (orchard grass, vernal grass, Bermuda grass and timothy grass), and mixed weed (ragweed, mugwort, oxeye daisy, dandelion and goldenrod)). Positivity of serum aeroallergen-specific IgE was defined as ≥0.35 UA/mL.21 (
link) In all patients, serum specific IgEs against house dust and house dust mite were tested. The major component of house dust is house dust mite, though it includes house dust mite, animal dander, and mold.
Demographic characteristics and other variables listed above were assessed at baseline. Response to omalizumab treatment was then assessed in all patients. Demographic characteristics and other variables, including the positive ratio of serum specific IgE of each subgroup, were next compared between responders and non-responders. Univariate and multivariate logistic regression analyses were finally performed to clarify the predictors of responsiveness to omalizumab. Treatment responsiveness to omalizumab was determined by physicians’ overall evaluation according to the GETE scale at 52 weeks.22 (
link) GETE is a five-point scale: excellent (complete control of asthma), good (marked improvement), moderate (discernible, but limited improvement), poor (no appreciable change), and worsening (overall deterioration of asthma control). Patients with an “excellent” or “good” response were defined as responders.
This study was approved by the Ethics Committee of Nagoya City University (60-20-0174). Written informed consent was waived by the ethics committee due to the retrospective nature of this study. Instead, an opt-out document was posted on the hospital website to offer patients the opportunity to refuse participation.
Tajiri T., Suzuki M., Kutsuna T., Nishiyama H., Ito K., Takeda N., Fukumitsu K., Kanemitsu Y., Fukuda S., Umemura T., Ohkubo H., Maeno K., Ito Y., Oguri T., Takemura M., Yoshikawa K, & Niimi A. (2023). Specific IgE Response and Omalizumab Responsiveness in Severe Allergic Asthma. Journal of Asthma and Allergy, 16, 149-157.