Features of secretory immunoglobulin a in patients after COVID-19 infection

Secretory immunoglobulin A, as a marker of the immune response in the mucous membrane, is an available indicator for detecting changes in the local immunity of mucous patients who have undergone COVID-19. Objective. To evaluate the dynamics of changes in the level of sIgA in saliva samples and the effectiveness of the use of interferon α-2b in individuals after a coronavirus infection. Patients and methods. Patients aged 18 to 60 years after COVID-19 infection (group 1 on therapy, n = 65; group 2 without therapy, n = 65) and conditionally healthy individuals (control group, n = 15) were monitored. The material is saliva samples, where the sIgA level was determined initially and after a month. The drug – interferon α-2b, in the form of a gel for topical use (Viferon®, dosage 36,000 IU/g) was administered intranasally 2 times a day, for 1 month. Results. In all groups of patients who underwent COVID-19, the level of saliva sIgA was lower compared to the conditional norm of healthy individuals (6,45 ± 1,81 mg/ml). A month after the administration of interferon α-2b the best effect was observed in patients in the time interval of 1–3 months from the infection, where sIgA was noted a statistically significant increase from 1,84 ± 0,28 to 5,78 ± 1,96 mg/ml. In the groups of patients with later terms, a moderate increase in sIgA was determined (3–6 months: 2,83 ± 0,71 to 3,33 ± 1,78 mg/ml; 6–9 months: 3,53 ± 0,45 to 4,76 ± 2,3 mg/ml) and the absence of infectious diseases during rehabilitation period. In the group without therapy, in all temporal aspects, a persistent decrease in sIgA indicators below normal values was revealed, and the frequency of incidence of respiratory viral infections was noted in 9,2% of cases. Conclusions. During the rehabilitation period, the greatest changes in sIgA in saliva were observed in patients in the first 3 months after the COVID infection. The administration of interferon α-2b to patients in the post-COVID period is accompanied by the normalization of sIgA and prevents the development of respiratory infections. In similar groups, after COVID-19 without therapy, the indicator tends to decrease, and this category of people is at a higher risk of developing other infectious pathologies. Key words: interferon α-2b, COVID-19, mucosal immunity, post-COVID period, secretory immunoglobulin A, saliva