Seasonal omalizumab reduces allergen-specific immunoglobulin E levels in patients with Japanese cedar pollinosis and asthma.

In Japan, Japanese cedar pollinosis (JCP) is one of the most prevalent forms of seasonal allergic rhinitis (AR). The JC pollen scattering period starts at the beginning of February and finishes at the end of April. JCP and asthma present concurrently; a previous survey showed that the prevalence of JCP in patients with asthma might be up to 30%--50%. Moreover, JCP is often associated with exacerbations of asthma. Therefore, JCP is a significant social problem in Japan. Pharmacotherapy for JCP includes histamine H1 receptor antagonist (HRA), leukotriene receptor antagonist (LTRA), and intranasal corticosteroid (INS). In addition, allergen-specific immunotherapy (ASI), including sublingual and subcutaneous immunotherapy, and antibody therapy, including omalizumab, are considered. ASI has been recognized as the only immunomodulatory therapy that can change the course of allergic disease by inducing allergen-specific immune tolerance, which may be associated with decreases in allergen-specific immunoglobulin E (sIgE) levels. Here we report five cases with JCP and asthma, whose sIgE levels against JC pollen are reduced by seasonal omalizumab treatment. Five consecutive patients with asthma and JCP, who were followed up at Mitsubishi Kyoto Hospital and continuously treated with seasonal omalizumab for at least three consecutive years from December 2009 to May 2017, were retrospectively evaluated. Data regarding clinical characteristics, including age, body weight, height, smoking status, pulmonary function test, fractional exhaled nitric oxide, and blood test, were collected from medical records. The dose