Background: Allergic rhinitis is a common disorder with great morbidity. Its prevalence has increased during recent years, therefore attracting attentions to its mechanisms. Type 2 cytokines play a major role in allergies. It has been proposed that Natural killer (NK) cells may be able to produce type 2 cytokines. This study was done to evaluate NK cells number and subtypes in patients with allergic rhinitis, comparing healthy subjects.
Methods: In a case control study, patients with allergic rhinitis were compared to healthy non-atopic subjects. Allergic rhinitis was diagnosed according to ARIA guidelines. NK cells quantity was studied by staining of peripheral blood mono nuclear cells with anti-CD16-FITC and anti-CD56-PE and evaluated by two color flowcytometry. Intracellular cytokines were evaluated by tri-color flowcytometry. NK cells were separated by magnetic beads, and cultured for 72 hours. Secretion of IL-4, IL-5, IL-10, IL-13, and IFN-γ was measured by ELISA, in stimulated and unstimulated conditions.
Results: Patients had more CD16+ CD56+ NK cells than control group. IL-4+ NK cells were significantly higher in patients (p<0.001), but the number of IFN-γ+ NK cells was not different. Cytokine secretion of NK cells was similar in case and control groups. Although IL-13 level after stimulation seemed higher in patients, the difference was not significant.
Conclusion: NK cells number is increased in patients with allergic rhinitis and a considerable number of them produce IL-4.