Activity of free radical processes in oral fluid of patients with recurrent upper respiratory tract infections

Background: Upper respiratory tract infections occupy a leading position in the infectious pathology. According to the World Health Organization (WHO), up to 500 million people fall ill with acute respiratory infections in the world every year, of which 2 million people die from various complications. At the same time, a number of researchers note the lack of methods for clinical and laboratory assessment of the condition of patients with this pathology. Aims: To evaluate the parameters of free radical oxidation in oral fluid of patients with recurrent upper respiratory tract infections (RIURT). Methods: The study involved 64 apparently healthy people who suffered respiratory infections up to 2 times a year, and 85 patients with RIURT (4 or more times a year), who at the time of the study were in remission. The determination of the parameters of the pro / antioxidant systems was carried out using two methods (photometric: the content of lipid peroxidation products and the level of ceruloplasmin and luminol-dependent chemiluminescence (LDCL) were measured, making it possible to assess the complex interaction of two systems — prooxidants and antioxidants). Results: The studies have demonstrated that, for most of the RIURT patients during remission, the levels of certain prooxidant components (diene conjugates, ketodienes, Schiff bases), as well as of an oral fluid antioxidant (ADS: ceruloplasmin) were elevated compared to the controls. At the same time, the LDCL parameters of oral fluid did not go beyond the reference interval, although they were changed relative to the median of the control group. This allows us to consider the observed fluctuations as a balance in the system of pro- and antioxidants. Conclusions. The use of oral fluid as a biological material for the assessment of the pro-/antioxidant system opens up new possibilities in the diagnosis of respiratory disease.