Study of IL-35 levels in blood and nasal fluid in children with allergic rhinitis

Allergic rhinitis (AR) is a common pediatric problem with significant comorbidities and complications. AR is an inflammatory disease of the nasal mucosa that causes symptoms such as nasal discharge, itching, sneezing, and obstruction after contact with the allergen, immunoglobulin (Ig) E-mediated. AR affects approximately 20-40% of the entire world population and its prevalence is increasing. In a study conducted by the Turkish Thoracic Society in 14 different centers, the median frequency of allergic rhinitis in childhood was found to be 17.2% (12.7% -26.7%). Symptoms of allergic rhinitis cause serious distraction, cognitive impairment, snoring, sleep disturbance, and consequently disruption and failure in school and work life, affecting people's social life and quality of life negatively. Together with all these negativities, the cost of examination and treatment during the course of the disease, the loss of work/school days and productivity causes an important economic burden, causing allergic rhinitis to be seen as a global health problem. Studies have shown that different cytokines and cytokine groups play an important role in the pathogenesis of AR. In the literature, it has been observed that serum interleukin (IL) -35 levels are low in individuals with allergic diseases. Although there are few studies in the literature showing that nasal IL-35 administration suppresses the symptoms of allergic rhinitis, there is no study measuring IL-35 level in nasal fluid. It has been shown that IL-35 inhibits the allergic T cell response, which plays a role in AR pathogenesis, has an anti-inflammatory effect in respiratory allergic diseases, and suppresses allergic symptoms by inhibiting pro-inflammatory cytokines and may be a new target in AR treatment. In our study, a total of 39 patients diagnosed with allergic rhinitis in our Pediatric Allergy Diseases and Child Health Polyclinics between June 2020 and August 2020 and 32 healthy children as a control group were included in the study. In both groups, C-Reactive Protein (CRP) in the blood to measure inflammation, total IgE and eosinophil values ​​were measured in terms of allergy screening and to support the presence of atopy, and allergy skin test was performed. IL-35 levels were studied in nasal secretion and blood. In this way, it was aimed to investigate IL-35 levels in blood and nasal fluid in patients with allergic rhinitis. At the end of our study, both peripheral blood IL-35 levels and nasal secretion IL-35 levels were found to be significantly lower in patients with AR than in the healthy group. These results suggested that IL-35 plays an important role in AR pathogenesis and could be a target in treatment. Keywords: Allergic rhinitis, child, allergen, atopy, cytokine