Zdorovʹe Rebenka (Oct 2015)
The Particularities of Airway Hyperresponsiveness to Histamine in Bronchial Asthma School-Age Children in Different Inflammatory Phenotypes
Abstract
On the base of the Chernivtsy Regional Children Clinical Hospital the diagnostic value of the indices of airway hyperresponsiveness to histamine for a verification of asthma inflammatory phenotypes have been studied in 83 school age children with persistent bronchial asthma. The first (I) clinical group consisted of 47 (56,6 %) children with eosinophilic asthma phenotype. The second (II) clinical group included the remaining 36 (43,4 %) patients with non-eosinophilic/neutrophilic bronchial asthma. The non-specific bronchial hyperresposiveness to direct stimuli using spirometric provocative test with inhalation of the serial dilutions of histamine has been performed by the method of E.F. Juniper (1994). There have been calculated such indices: provocative concentration of histamine (PC20H), provocative dose of histamine (PD20H) and dose-response slope. To evaluate the diagnostic value of the tests their sensitivity, specificity, the positive and negative predictive values have been measured. Bronchial provocation test with inhalation of serial dilutions of histamine should be used for bronchial asthma verification in school-age children. Namely PC20H < 8.0 mg/ml appears highly sensitive screening test (95 %) in the diagnosis of different inflammatory asthma phenotypes. None of the indices of non-specific bronchial hyperresponsiveness to histamine can be used independently as a screening method for verification of eosinophilic asthma phenotype because of the high incidence of false negative results. The index of bronchial hyperresponsiveness to histamine (dose-relative slope ≥ 3.0 arbitrary units) is the most informative to confirm eosinophilic asthma phenotype due to the high specificity of the test (94 %) and a small number (17 %) of a false diagnosis of eosinophil-associated airway inflammation in its absence.
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