Activation of Eosinophils Is More Closely Linked with Interleukin-5 and Nitric Oxide Production than Tumor Necrosis Factor-α and Immunoglobulin E Levels

Abstract

Patients were eligible if they had the following: (1) a documented clinical history of acute asthma, (2) positive results for sIgE test (aeroand/or food allergens according to the ImmunoCAP test), and (3) elevated serum total IgE (tIgE) levels to confirm allergy. The exclusion criteria were as follows: (1) medication history including corticosteroids or histamine antagonists, (2) concurrent systemic infection with fever (>37.5 ° C), or (3) chronic illness. The following parameters were measured: eosinophil parameters (ECP and ECP/Eo ratio), IgE-related parameters (sIgE score and tIgE level), cytokines (IL-5 and TNF-α), and inflammatory parameters [NOx metabolites and high-sensitivity C-reactive protein (hsCRP)]. The serum ECP concentration was measured using a solid-phase, 2-site chemiluminescent immunometric assay on an Immulite 2000 analyzer (Siemens Healthcare Diagnostics, Tarrytown, N.Y., USA). The cutoff limit for a positive serum ECP result was set at >19 μg/l on the basis of the manufacturer’s instruction. sIgE was measured for 2 major inhalant allergens (Dermatophagoides pteronyssinus and D. farinae) and 2 food allergens (egg white and cow’s milk) using a fluoroenzyme immunoassay system (ImmunoCAP 100, Phadia AB, Uppsala, Sweden). sIgE concentrations >0.35 kU/l Eosinophils contain several proinflammatory mediators and are implicated in the initiation of diverse inflammatory responses [1] . Eosinophil cationic protein (ECP) is produced in eosinophilic progenitors, stored in cytoplasmic granules of mature eosinophils, and released from activated eosinophils [2, 3] . The ratio of serum ECP concentrations to peripheral blood eosinophil counts (ECP/Eo ratio) reflects the number of ECP molecules per circulating eosinophil, which is regarded as a potential indicator of eosinophil activation [4, 5] . Few studies have closely examined the relationships between the activation of eosinophils and the production of nitric oxide (NOx) and cytokines. The present study investigated the associations between eosinophil activation and the levels of interleukin-5 (IL-5), tumor necrosis factor-α (TNF-α), NOx metabolites, and allergen-specific immunoglobulin E (sIgE) scores. A total of 112 patients with acute bronchial asthma (57 males and 55 females) aged 3.2–9.5 years (median 6) were investigated. Ageand gender-matched healthy subjects (n = 25) were evaluated as a control group, who had no evidence of allergic diseases and atopic sensitization based on skin-prick test results. Received: January 9, 2013 Accepted after revision: February 17, 2013 Published online: July 11, 2013