Summary. Diseases of the paranasal sinuses (DPN) are the most common pathology in otorhinolaryngology. According to the literature, it is known that cystic sinusitis is an infectious and allergic disease, and the formation of cysts is considered as the result of an allergic reaction to infection in sensitized patients. Adverse environmental impact on the immunological system of the human body, reducing natural resistance, increasing the degree of allergization of the population contributes to a high level of General respiratory diseases. In this regard, it is relevant to study the indicators of General and local immunity in patients with chronic cystic sinusitis. We examined 138 patients with chronic cystic sinusitis aged 17 to 64 years. Conducted immunological study of the state of cellular and humoral immunity in accordance with the recommendations Of the Institute of immunology. A comprehensive immunological examination revealed a sharp imbalance of immunological parameters in blood serum, nasal flushes and cystic fluid in patients with chronic cystic sinusitis. In the complex of etiological and pathogenetic treatment in patients suffering from chronic cystic sinusitis, it is necessary to include immunodulators and immunostimulators.Introduction . Diseases of the paranasal sinuses (DPN), sinusitis-are among the most common pathologies in otorhinolaryngology[3,6]. This is facilitated by changes in the environmental situation in the world, the wide prevalence of both allergic and viral respiratory diseases, the irrational use of antibacterial drugs, and a decrease in local and General immune mechanisms. According to the literature, it is known that cystic sinusitis is an infectious and allergic disease. The formation of cysts is considered as a result of an allergic reaction to infection in sensitized patients. To date, the causes of cysts have not been clarified, so it remains relevant to further in-depth study of various factors that may affect the course of the inflammatory process. In a modern city, a person is exposed to a complex of environmental factors that adversely affect their health. The leading one is multi-complex air pollution, which occurs as a result of intensive development of industry and transport . We have identified an adverse effect of environment on the immune system of the human body - the formation of secondary immunosuppression, reduced natural resistance, increase the degree of allergization of the population, resulting in high rates of overall morbidity and, in the first place, the defeat of the respiratory tract that is characterized by high radiation, dust and fumes in the environment.Currently, the influence of three factors - dust, carbon monoxide and sulfur dioxide-on the incidence of acute respiratory infections, bronchitis and pneumonia has been reliably proven. These agents and their various combinations affect the incidence of angina, pharyngitis, rhinitis, and sinusitis [5,8]. The increased content of harmful substances in the inhaled air has not only a General adverse effect on the body, but also leads to a violation of their normal functioning of the nasal cavity, i.e. weakens its protective capabilities, which increases the risk of rhinitis and sinusitis.In connection with the above, it was considered relevant to study the indicators of General and local immunity in patients with chronic cystic sinusitis [2,4,7,9].The aim of the study was the state of immunological reactivity in patients with chronic cystic sinusitis.Materials and methods of research. 138 patients with chronic cystic sinusitis aged 17 to 64 years were examined, including 65 women (47%) and 73 men (53%) who applied to the clinic No. 1 of the Samarkand medical Institute. The number of workers and employees was about the same. For examination, patients with chronic cystic sinusitis were selected with a prescription of this pathology for at least 2 years and there were no concomitant inflammatory diseases. The diagnosis was made on the basis of patient complaints, anamnesis data documented in outpatient records, clinical manifestations of the disease, x-ray, computed tomography examination of the paranasal sinuses (PNS) and the results of maxillary sinus puncture. To determine the regional physiological norm, all the indicators used were determined in 54 clinically healthy donors aged 17 to 50 years of both sexes from the number of volunteers with no history of chronic inflammatory diseases. Immunological indicators of the physiological norm in flushes from the maxillary sinuses were determined in 23 healthy persons from the number of military conscripts. The conducted immunological study included a detailed determination of 3 links of the immune system: all stages of phagocytosis (% of phagocytic cells, phagocytic number and phagocytosis completion index - PCI) and nst-test, rosette formation reactions - active, spontaneous, and with loads of levamizol and theophylline, concentrations of immunoglobulins of classes A, M, G and sec - rotary Ig A, as well as the content of lysozyme and circulating immune complexes (CIC).We studied the state of cellular and humoral immunity according to the recommendations Of the Institute of immunology. Blood for research was taken in the morning on an empty stomach from the ulnar vein. To determine the cellular level of immunity, blood was placed in a heparinized test tube at the rate of 20 units of heparin per 1 ml of blood. The isolation of immunocompetent cells was performed by a conventional method using a ficol-verografin gradient. Mononuclear suspension was studied in a cell concentration of at least 1 million cells per 1 ml.To study the state of local immunity, cystic fluid was used, which was obtained by means of a diagnostic puncture of the maxillary sinus and was aspirated into a sterile syringe. Further calculations took into account the 1:10 dilution.Results and discussion. A comprehensive immunological examination revealed a sharp imbalance of immunological parameters in blood serum in patients with chronic cystic sinusitis. First of all, attention is drawn to the marked decrease in all indicators of serum immunoglobulin content, as well as secretory Ig A (table 1). It should be noted that the physiological norm of the content of immunoglobulins in blood serum is located within a fairly wide range. For example, the amplitude of ”normal” values for Ig A is from 1.7 to 2.55 g / l, and for SIgA-from 1.65 to 2.65. The same significant fluctuation in their indicators is observed in patients with chronic cystic sinusitis. It seems more convenient to use this indicator in the form of the Ig a/ SIgA index in practical health care . In healthy patients, it is equal to 1, i.e. 1: 1, and in patients with chronic cystic sinusitis, it changes significantly and is 3:1.in all the examined patients, this index was the most constant value, i.e. its fluctuations were minimal.Analyzing the phenomenon of a sharp decrease in the content of immunoglobulins of all classes in the examined patients, it can be assumed that this is a manifestation of a fairly common congenital immunodeficiency condition in all classes of immunoglobulins. In the literature, this category of patients is described as a group of frequently and long-term patients. In most cases, the anamnesis data corresponds to this description.When further analyzing the results of immunological examination of individuals with chronic cystic sinusitis, the following Genesis of the phenomenon of deficiency in all classes of immunoglobulins seems more likely, namely: characterizing the indicators of the macrophage system, it should be noted that the percentage of phagocytic cells is usually increased, which is quite consistent with the classical course of the inflammatory process, but the ability of phagocytes to capture and digest the pathogenic object is reduced (table 2).In this case, we are probably dealing with a congenital defect of the a-link of the immune system, which entails, according to the theory of the three-link immune system, a weak immunological signal to the B-link. Thus, the decrease in serum levels of immunoglobulins of all classes in patients with chronic cystic sinusitis appears to be mediated.This assumption is supported by such an increase in the value of the nst test to 56.5+3.4 (with a norm of 22.5-2.3).Defect A-link - bad recognition, capture and digestion of pathogen - creates conditions for the transition of the inflammatory process in chronic, since it entails a high concentration of this agent in the patient’s body, i.e., a high degree of sensitization, as manifested in the examined in the reaction of immunoparalysis.The high percentage of phagocytic cells and the increased values of the nst test are obviously compensatory. Describing the indicators of the T-system in chronic purulent sinusitis (table 3), it should be noted that the number of active test on the formation of the rosette in the resection reaction in these patients is slightly increased compared to the norm, but statistically unreliable.During stress tests, a decrease in test on the formation of the rosette with theophylline was detected, while the indicators of spontaneous tissue-forming test on the formation of the rosette cells with levamisole almost coincide with the lower limit of the norm, i.e. they are statistically unreliable.The most interesting indicator here is already known and actively used by immunologists index-the ratio of T-helper /T-suppressor: normally in healthy people, it is 0.5+0.03 or 1:2, and in patients with chronic purulent sinusitis, its indicator was significantly changed and took the value of 1.16+0.04, which corresponds to the ratio of 1:1 .Analyzing the state of non-specific resistance, we noted a significantly increased concentration of CIC in the blood serum in patients with chronic cystic sinusitis (98.7+8.2 units of opt.pl) compared to the norm (25:3.2 units of opt. pl). A high level of CIC corresponds to the immunological manifestations of chronic inflammation in the body and may reflect the failure of the phagocytosis process.The detected decrease in the lysozyme index in blood serum - 3.28+0.18 mkg/l (at the norm of 3.7±0.09 mkg/l) may be a sign of exhaustion of this system due to the age and severity of the inflammatory process occurring against the background of a defect in the a-link of the immune system. The immunological characteristics of patients with chronic cystic sinusitis are supplemented by a study from the maxillary sinuses, the results of which are presented in table 4.In cystic fluid in chronic cystic sinusitis, there is an almost double increase in the content of serum Ig A, Ig G and a noticeable decrease in serum Ig and secretory lgA compared to the same indicators in healthy volunteers. This ratio of serum immunoglobulins is quite consistent with the reaction of the B-link immunity to chronic inflammatory process, but a significant decrease in the content of SigA, apparently, pathognomonic for this category of patients, because it reflects the initial weakness of the local immune system of the nasal cavity and paranasal sinuses.In flushes, as in blood, with a wide range of values of Ig A and SigA, the ratio of Ig A/Slg a was the least subject to fluctuations and at the same time the most constant. In healthy patients, it was 0.98+0.032, and in patients-1.86-0.04. For convenience, we have expressed this ratio in the form of an ”immunoglobulin” index, which is 1:1 in healthy people and 2:1 in patients.Indicators of non-specific resistance in cystic fluid from the maxillary sinuses in chronic cystic sinusitis are presented in table 5.An increase of almost twice the normal CIC content in flushes from inflamed maxillary sinuses corresponds to immunological manifestations of the inflammatory process.The fact that in the body of patients with chronic cystic sinusitis, the level of CIC is increased both in the blood serum and in sinus flushes, suggests a possible participation of the autoimmune process in the pathogenesis of this disease.The content of lysozyme in flushes from the maxillary sinuses, as well as in the blood serum, is reduced. Obviously, this phenomenon is still systemic. It is possible that the reduced antibacterial capabilities of local immune factors in the maxillary sinus-secretory immunoglobulin and lysozyme are a predisposing factor in the formation of a chronic process in this organ.