Correlation between cytokine levels in nasal fluid and eosinophil counts in nasal polyp tissue in asthmatic and non-asthmatic patients.

Background/aims: Concentrations of mediators in nasal secretions could reflect the inflammatory status of the nasal mucosa and evolution of sinus disease. So, the aim of our study was to evaluate local immune reaction by measuring crucial Th1, Th2 and inflammatory cytokines in nasal fluid samples of patients with nasal polyps (NP), and to correlate them to clinical, radiological findings and to the degree of eosinophil infiltration of polyp tissue. Therefore, in our study we compared the cytokine levels in nasal fluid of asthmatic and non-asthmatic patients with nasal polyposis, the eosinophil counts in NP tissues of these patients, and we correlated cytokine levels with eosinophil counts in NP tissue specimens.

Material And Methods: Thirty patients with nasal polyposis (NP) (15 asthmatic and 15 non-asthmatic) were included in this prospective study. Nasal secretion samples were collected from nasal cavities of all subjects. The levels of 11 cytokines (TNF-α, TNF-β, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, and IFN-γ) were measured using commercial flow cytometric kit. Eosinophils were counted in haematoxylin-and-eosin-stained NP sections.

Results: The concentrations of Th2 cytokines IL-5, IL-6, IL-10, and Th1 cytokine IFN-γ were significantly higher in patients with NP and asthma compared with non-asthmatic subjects. A positive correlation was found between IL-6 and TNF-α levels in nasal fluid and eosinophil counts in polyp tissue in non-asthmatic subjects. In asthmatic NP patients, we found positive correlation between level of IL-6 and eosinophil counts and negative correlation between IFN-γ level and number of eosinophils in NP tissue specimens.

Conclusion: Our results showed that these patients with similar clinical findings had significantly different mediator profiles in their nasal secretions, implying clear differences in pathogenesis of their NP.