Evaluation of FcεRI-Bindable Human Ige With an Enzyme-Linked Immunosorbent Assay Using a Recombinant Soluble form of the Human FcεRIα Ectodomain

To estimate the levels of serum IgE that is actually able to be bound to FcεRI, we developed a novel enzyme-linked immunosorbent assay (ELISA) using a recombinant soluble form of the human FcεRIα ectodomain (soluble α-ELISA). We evaluated the levels of FcεRI-bindable serum IgE in normal volunteers and in patients with atopic dermatitis and bronchial asthma, and compared them with those of total IgE measured by a conventional sandwich-ELISA. There was a striking difference between the IgE values evaluated with these two ELISA systems. In most of the sera, the IgE values evaluated with the soluble α-ELISA were substantially lower than those evaluated with the sandwich-ELISA. Our results indicate that all serum IgE (especially in hyper-lgE sera) does not necessarily bind to the FcεRI and that it will be useful to evaluate FcεRI-bindable IgE for further analysis of allergic states

Evaluation of FcεRl-binding serum IgE in patients with ocular allergic diseases

We evaluated high-affinity receptor for IgE (FcεRI)- binding serum IgE in patients with atopic keratoconjunctivitis (AKC; n=31) and with seasonal allergic conjunctivitis (SAC; n=13) by enzyme-linked immunosorbent assay (ELISA) using a recombinant soluble form of the human FcεRIα ectodomain (soluble α). The quantities of FcεRI-binding IgE are compared with those of total IgE measured by a conventional sandwich ELISA. Both of the quantities of FcεRI-binding and total IgE in AKC were significantly larger than those in SAC (P<0.001). In contrast, the proportion of FcεRI- binding IgE (FcεRI-binding IgE/total IgE; %) in SAC was significantly larger than that in AKC (P <0.001), although significant reverse correlation was observed between the proportion of FcεRI-binding IgE and total IgE in both AKC and SAC. Significantly, a higher proportion of FcεRI-binding IgE in SAC than that in AKC may reflect the differences in pathologic states of AKC and SAC that are caused by a disparity in immune responses in these diseases

Detection of anti-IgE anti-FcεRI α chain auto-antibodies in patients with atopic dermatitis

Anti-IgE and anti-FcεRI α chain auto-antibodies have been detected in the sera of atopic and non-atopic subjects; however, the biological activity of these auto-antibodies is still unclear. These two kinds of autoantibodies were examined in atopic dermatitis (AD) patients. In results, 12 of 92 AD patients have the anti-IgE, eight have the anti-FcεRI α auto-antibodies and two have both auto-antibodies. Furthermore, biological characterization of these auto-antibodies has been performed. In results, three of 12 samples with the anti-IgE auto-antibodies exhibited inhibitory activity for IgE-FcεRI α binding. Two of the eight samples with the anti-FcεRI α auto-antibodies and one of the two samples with both auto-antibodies had histamine releasing activity. It is documented here that both anti-IgE and anti-FcεRI α auto-antibodies were detected in some AD patients, some anti-IgE auto-antibodies had inhibitory activity for IgE-FcεRI binding and also histamine releasing activity was detected in the anti-FcεRI α chain auto-antibody

Exercise challenge in patients with asthma whose peak expiratory flow values are controlled within the green zone

Recent guidelines for the management of asthma recommend that peak expiratory flow (PEF) should be measured to monitor the level of airflow limitation and to maintain PEF values within the green zone (80–100% of the patient's highest PEF value). Because no studies have evaluated the efficacy of PEF zone management on the basis of patients' physical activity, we studied the appearance of exercise-induced asthma (EIA) using treadmill exercise challenging in asthma patients whose PEF values had been maintained in the green zone for at least 3 months. Exercise-induced asthma was induced in nine of 44 (20.5%) asthma patients. The acetylcholine concentration required to cause a 20% fall in forced expiratory volume in 1 s (log PC20) was significantly lower in patients with EIA (2.39±0.21 μg/mL) compared with patients without EIA (3.22±0.12 μg/mL; P <0.03). These results suggest that PEF green zone management alone does not ensure the ability to perform vigorous physical activity, especially in patients whose airway reactivity remains enhanced. Therefore, airway reactivity should be considered for asthma management

Effect of a leukotriene receptor antagonist pranlukast hydrate, on airway inflammation airway hyperresponsiveness in patients with moderate to severe asthma

Asthma is characterized by chronic airway inflammation and the recruitment of inflammatory cells, typically eosinophils and lymphocytes, into the airway. Although several chemical mediators are released during the inflammatory process of asthma, evidence strongly suggests that the cysteinyl leukotrienes (LT), LTC4, LTD4, and LTE4, play key roles in asthma. The short-term clinical efficacy of an LT receptor antagonist, pranlukast hydrate, in symptomatic patients with asthma who had already been treated with moderate to high doses of inhaled corticosteroids was therefore investigated. Treatment with pranlukast hydrate for 4 weeks significantly improved respiratory function and decreased asthma symptoms, the rescue use of inhaled β2-agonists, the number of peripheral blood eosinophils and serum levels of eosinophil cationic protein. Furthermore, airway inflammation, as evaluated by the percentage of eosinophils in induced sputum and airway responsiveness to histamine, decreased significantly after treatment. There were no significant changes in these parameters in control patients with asthma whose treatment was not changed over 4 weeks. These preliminary results suggest that pranlukast hydrate, an LT receptor antagonist, is an effective agent in the management of asthma in combination with moderate to high doses of inhaled corticosteroids