The Effect of Omalizumab on Eosinophilic Inflammation of the Respiratory Tract in Patients with Allergic Asthma

Bronchial asthma is characterised by high levels of immunoglobulin E (IgE) and overproduction of pro-inflammatory cytokines, including interleukins IL-4, IL-13 and IL-5 needed for, amongst other things, the production of IgE and the differentiation, maturation, migration and survival of eosinophils. Eosinophils are one of the most important cells in allergic inflammation. Their presence in tissue is linked to the persistence of inflammatory infiltrate, tissue damage and remodelling. Although these cells are very sensitive to corticosteroids, some asthmatic patients do not respond to high doses of these drugs, even when administered systemically. Transbronchial biopsies and bronchoalveolar lavage performed in patients with steroid-resistant asthma have demonstrated higher levels of eosinophils and Th2-type cytokines (IL-4 and IL-5) compared to steroid-sensitive patients. Clinical studies have confirmed that the very effective treatment in these cases is therapy with omalizumab—an anti-IgE monoclonal antibody. The paper discusses the efficacy of omalizumab in reducing eosinophil number in peripheral blood and in the airways of asthmatic patients based on basic, clinical, observational studies and case reports. The significance of omalizumab therapy in asthma control and mechanisms that regulate the effects of omalizumab on eosinophils are evaluated.