Nasal fluid sample as a reliable matrix for determination of cytokine levels in childhood asthma

Objectives: Childhood asthma is a chronic disease with high incidence worldwide. As a lifelong disease, asthma has episodes. Inflammation continues to occur in the clinical remission of asthma. It can be difficult to diagnose childhood asthma, especially in clinical remission. We hypothesized that some cytokines secreted to nasal fluid from the airway during inflammation might help diagnose clinical remission of asthma. Moreover, sampling nasal fluid is an easy and non-invasive procedure, so it may be a preferable sampling method.Methods: We measured levels of some interleukins (ILs), which are IL-4, IL-5, IL-6, IL-12p70, IL-13, IL-33, granulocyte-macrophage colony-stimulating factor (GM-CSF), periostin and thymic stromal lymphopoietin (TSLP) by Luminex magnetic bead-based immunoassay in nasal fluid and in serum of asthmatic children in clinical remission.Results: We found that IL-5, IL-6, IL-33, and periostin had elevated levels in nasal fluid. IL-5 and IL-33 had increased levels in the nasal fluid of the patients with immunoglobulin E (IgE) high and low phenotypes. While the nasal fluid TSLP levels were positively correlated with most of the increased serum cytokine levels of non-allergic asthmatic children, the nasal fluid GM-CSF levels were positively correlated with most of the increased serum cytokine levels of the allergic asthmatic children.Conclusions: IL-5, IL-6, IL-33, and periostin had elevated levels in the nasal fluid of the patients in clinical remission. The nasal fluid GM-CSF levels of the allergic patients and nasal fluid TSLP levels of the non-allergic patients had a positive correlation with most of the serum cytokine levels. Thus, our results showed that nasal fluid might be a preferable biological sample to diagnose asthma in children.