Induced Sputum Versus Exhaled Nitric Oxide for the Evaluation of Airway Inflammation in Allergic Pediatric Asthma Patients Treated With Omalizumab

Abstract

SESSION TITLE: Pediatric Asthma PostersSESSION TYPE: Original Investigation PosterPRESENTED ON: Wednesday, October 30, 2013 at 01:30 PM - 02:30 PMPURPOSE: To determine the inflammatory changes in the airways of allergic pediatric asthma patients treated with omalizumab, measured by the percentage of eosinophil in induced sputum and exhaled nitric oxide.METHODS: from 2006 to 2012, 31 patients with asthma were treated with omalizumab (15 male -51.6% ; 16 females -48,4%-). The age ranged between 6 -18 years. The dose of omalizumab was calculated according to the dosing table of the company. Omalizumab was administered subcutaneously in the day unit of the hospital. Protocol: at entry we obtained from every patient: a total IgE concentration, specific IgE against the most relevant allergen, the percentage of eosinophils in a smear of induced sputum and the exhaled fraction of nitric oxide (NO) (Niox Mino, Phadia). Induced sputum and NO were measured at the end of follow-up. Data are shown as mean (SEM). A Student t-test for paired data was used to compare the data.RESULTS: The follow-up of the patients was not uniform, ranging from 2 to 6 years. Total IgE concentration at entry: 668.89 (117.79) IU/mL; Specific IgE against the major antigen at entry: 42.15 (7.32) IU/mL; ( 22 house dust mite; 7 alternaria; 2 cladosporium). Intial and end induced sputum: 6.26 (2.03) % vs 2.47 (0.36) % ; (p< 0.05). Initial and end NO values: 19.04 (1.98) ppb vs 18.10 (2.11) ppb (p= NS).Three patients were excluded from the evaluation due to exagerated values in the final NO measurement that preceded a severe exacerbation.CONCLUSIONS: Omalizumab allowed a statistically significant decrease in the percentage of eosinophils in induced sputum of this cohort of patients. Although very sensible, NO is a less reproducible and thus less reliable method to evaluate chronic airway inflammation in a pediatric allergic population with uncontrolled severe asthma.CLINICAL IMPLICATIONS: Induced sputum seems to be a better method to monitor chronic inflammation and thus the response to chronic omalizumab treatment while NO measurement would be more useful to monitor acute events preceding exacerbations.DISCLOSURE: The following authors have nothing to disclose: Xavier Domingo, Montserrat Bosque, Laura Valdesoiro, Helena Larramona, Laura Vigil, Alba Maestro, Oscar Asensio, Christian DomingoNo Product/Research Disclosure Information.