Experience of SLIT in patients with bronchial asthma through the prism of the coronavirus infection pandemic

Background. The problem of the features of the course of allergic diseases against the background of the COVID-19 pandemic, as well as rational and safe approaches to their treatment, are in the focus of close attention of specialists. The article presents the results of the use of sublingual allergen-specific immunotherapy (SLIT) in the context of a coronavirus infection pandemic in patients with bronchial asthma (BA). Objective. Assessment of the clinical and immunological efficacy and safety of SLIT in the treatment of BA against the background of the COVID-19 pandemic. Methods. From 2017 to 2021, a retrospective study of the efficacy and safety of SLIT in comparison with the standard baseline therapy for patients with allergic BA caused by sensitization to the house dust mite was performed. The study included 72 patients with allergic BA, 42 of them received SLIT with Staloral “Tick Allergen" against the background of baseline anti-inflammatory therapy, 30 - only standard baseline anti-inflammatory therapy. Control of asthma symptoms and severity, demand for baseline therapy, the ACT test results, functional test data, allergic-immunological parameters (total IgE, asIgE to D. farinae and D. pteronyssinus allergens, diameter of scarification samples with etiotropic allergens) were assessed in over time. With the onset of the COVID-19 pandemic, namely from 2019 to 2021, the risk of COVID-19 infection was additionally assessed in all patients with BA. In the spring of 2019, patients were followed-up using telemedicine technologies. In the case of coronavirus infection, its severity and outcomes, as well as the effect on the course of BA, were evaluated. Parameters are presented as mean, median (Me) and quartiles [Р25%; P75%]. The results were considered statistically significant at p<0.05. Wilcoxon-test was used for the comparison of groups. Results. At the end of the three-year course of treatment, the clinical efficacy of SLIT with Staloral “Tick Allergen", taking into account the excellent and good results, was 92.8%. After 3 years, SLIT showed a statistically significant (p<0.05) decrease in the frequency of BA symptoms and exacerbations, and improvement of disease control. There was a decrease in the average dose of inhaled glucocortico-steroids by 1.7 times compared with the initial values (p<0.05). The frequency of exacerbations in patients of the first group decreased by 2.1 times, while in patients of the second group - by 1.1 times. In patients receiving SLIT, the BA control increased: the total ACT score decreased against the background of SLIT with Staloral “Tick Allergen" from 1.93 to 1.12 points, in patients of the second group this indicator was 2.1 (p<0.05). As a result of SLIT in BA patients, the total IgE level decreased by 1.8 times, asIgE to the house dust mite D. pteronyssinus - by 3.1 (from 4.21 to 1.37 kU/L), to the D. farinae mite - by 2 (from 5.90 to 2.89 kU/L), the diameter of skin tests - by 1.9 times (from 8.17 to 4.19; p<0.05). Mild local reactions to SLIT were recorded in 19.0% of cases. Since the start of the COVID-19 pandemic, SLIT has been temporarily withheld in 10 patients due to coronavirus infection. All infected patients had a mild clinical course of disease. No hospitalization and no BA exacerbation against the background of a viral infection was recorded. IgG antibodies were detected in 11 patients of both groups before the planned administration of the Sputnik-V vaccine, which indicated that they had an asymptomatic course of the disease. Thus, the results of this study demonstrate the need to use SLIT to optimize the treatment of allergic BA, and also indicate the safety and feasibility of this method in the context of the COVID-19 pandemic. Conclusion. SLIT is a safe, highly effective method of BA immunotherapy, which is possible despite the COVID-19 pandemic. BA patients receiving SLIT as part of baseline therapy are not at risk of developing severe COVID-19, which is associated with good BA control as a result of combined treatment.

COVID-19, bronchial asthma, baseline therapy, sublingual allergen-specific immunotherapy, pandemic, COVID-19