Inflammatory Action of Exhaled Breath Condensate from Children with Severe Asthma on Cultures of Human Respiratory Epithelium: Mechanisms and Relationship with Clinical and Functional Characteristics

<bold>Background:</bold> Exhaled Breath Condensate (EBC) of asthmatic patients is different to that of healthy subjects. We use EBC of children with Severe Asthma (SA) as an additive to cell culture medium in human respiratory epithelium cells cultures (HREC) and evaluate its effects. <bold>Aims:</bold> 1) assess if EBC from children with SA has proinflammatory effect on HREC; 2) correlate these results with clinical and functional characteristics; 3) characterize the mechanisms of any proinflammatory action. <bold>Methods:</bold> In children with SA who participated in a prospective observational study samples of EBC were collected. Anthropometry, physical examination, inhaler technique and treatment adherence were evaluated. Asthma Control Test (ACT), screening for SDB (PSQ), spirometry, and FeNO measurement were performed. Cells from a human respiratory epithelium cell line (Calu-3) were cultured and aliquots of the EBC were added to cultures. The release of IL-6 to the supernatant was assessed (ELISA technique). The association between the levels of IL-6 released and the characteristics of the patients was estimated. <bold>Results:</bold> 96 children (96 EBC samples): 30% overweight, 74% controlled asthma, 14% FEV1 < 80%, 41% SDB, 46% rhinitis. 31 samples of EBC (32%) induce IL-6 liberation by cell cultures. Overweight was statistically associated with the absence of IL-6 liberation (p 0.002). In OW children the concentration of liberated IL-6 negatively correlates with BMI (R 0.36; p 0.05). <bold>Conclusions:</bold> EBC of OW SA children affects respiratory epithelium cultures in a different way than EBC of normoweigth SA children.