STUDY OF SOME ASPECTS OF IL-5 ROLE IN THE ALLERGIC RESPIRATORY PATHOLOGY-ALLERGIC RHINITIS AND ASSOCIATED BRONCHIAL ASTHMA

Abstract

Background: A lot of evidence exists on the relationship between the upper and lower respiratory airways based on epidemiological, clinical, and pathophysiological levels. However, new aspects of allergic inflammation and released cytokines play a crucial role in this interaction. This study aims to explore the role and involvement of IL-5 in patients with allergic rhinitis (AR) and newly diagnosed allergic bronchial asthma (BA) with a mild course, manifested after many years of previous persistent AR. Methods: This prospective study included 67 patients with allergic inflammation of the upper respiratory airways, manifested by AR, and involvement of the lower airways, clinically presented as mild atopic BA, recruited between 2020 and 2021. Results: AR patients were 35 (40.23%), and patients with a combination of AR and newly diagnosed BA - 32 (36.78%). Twenty healthy controls (22.99%) were also included. The most common type of sensitization was to grass pollen 43 (64%) and tree pollen - birch 32 (48%). We did not find significant differences between the serum levels of healthy individuals and patients included in the study. No associations between the IL-5 levels and parameters of functional lung tests or skin prick tests were found. However, we have identified the following dependencies: IL-5 levels were lower in the patients than in the healthy subjects; however, non-significantly. This difference is more prominent when comparing the AR group of patients to the AR with BA group. Conclusions: Despite the known role and active involvement of IL-5 in allergic diseases, not always IL-5 levels can be found elevated in serum samples of AR and AR with BA patients. Therefore, other mechanisms may play a significant role in airway inflammation, primarily when one allergic disease occurs after another.