Background. Chronic polyposis rhinosinusitis is characterized by an immune-dependent type of polyp formation with a defect in local protective factors. The use of local immunomodulators will improve immune protection in the nasal cavity.
 Aim. To study cytokine levels in nasal secretion and blood serum in patients with chronic polyposis rhinosinusitis after therapy with interferon gamma.
 Material and methods. To study immunological indices, 32 patients with chronic polyposis rhinosinusitis, who were treated with intranasal interferon gamma, and 30 healthy people (control group) were examined. In the group of patients with the disease, the levels of interleukins-4, -10 and -18, tumor necrosis factor , and secretory immunoglobulin A were determined in the nasal secretion and blood serum before treatment and 1 month after it. Statistical analysis of the results was performed using the Statistica 12.0 software package. The test for normality of distribution in the sample was carried out using the ShapiroWilk test. Most of the parameters did not have a normal distribution; therefore, nonparametric statistical methods were used for further analysis. The description of the results obtained in the study was carried out by calculating the median (Me) and the interquantile range in the form of the 25th and 75th percentiles (Q0.25 and Q0.75). Comparative analysis of quantitative signs in independent groups was performed according to the MannWhitney test, in dependent groups using the Wilcoxon method. Differences were considered significant at p 0.05.
 Results. Clinical efficacy was assessed according to a 4-point scale: excellent treatment result, good result, satisfactory and unsatisfactory. A good effect of the therapy was 78.1% (25 patients). Unsatisfactory effect was registered in 7 (21.9%) patients. After treatment, a decrease in the content of interleukin-4 (p2=0.000034), interleukin-18 (p2=0.000075), an increase in the level of interleukin-10 (p2=0.033), a decrease in the amount of secretory immunoglobulin A in the nasal secretion (p2=0.0001) took place. The levels of tumor necrosis factor in blood serum were reduced both before treatment compared with the control group (p1=0.005) and after therapy (p2=0.000075).
 Conclusion. An increase in the content of interleukin-10 in the nasal secretion and a decrease in the level of proinflammatory cytokines interleukin-18, tumor necrosis factor and interleukin-4 in the blood serum after treatment with interferon gamma in patients with chronic polyposis rhinosinusitis may indicate a decrease in the activity of immune inflammation in the nasal cavity.