IMMUNE MECHANISMS FOR DEVELOPMENT OF CONTROLLED AND PARTIALLY CONTROLLED ASTHMA

Abstract

Despite a significant amount of works specifying immune mechanisms of bronchial asthma (BA), different phenotypes observed in this pathology need to be studied. The aim of present study was to analyze functional activity of Th1, Th2 и Th17 lymphocytes, and to determine features of inflammation in controlled and partly controlled asthma.We examined eighty-four BA patients that were divided into 2 groups, depending on the control of symptoms and the clinical course of BA. Group I included 45 patients with controlled BA, whereas group II included 39 patients with partially controlled asthma. The subsets of Th1, Th2, and Th17 lymphocytes were assessed by serum cytokine levels (TNFα, IFNγ, IL-2, IL-4, IL-6, IL-10, IL-17A) using flow cytometry technique.The results of this study were as follows: we have shown a combined T-helper (Th) immune response in asthma patients, with its origin depending on the degree of the disease control. Th2 (62%), Th1/Th2 (20%) and Th1 (18%) types of immune response have been detected in the patients with controlled BA. Th2/Th17 (49%), Th1/Th17 (13%) and Th17 (37%) types of immune response have been identified in the patients with partially controlled BA. It has been shown, that Th1 immune response in patients with controlled asthma is induced by intracellular infection. The formation of the Th1/Th2 phenotype is associated with a site of chronic bacterial infection revealed, and with persistence of viral infection in the body. This phenotype can be used as an indicator of asthma worsening. Further studies in the role of prevalent immune response type in the development of partially controlled BA have shown that activation of Th17 lymphocytes is associated with prolonged course of the disease. Irrespectively of initial phenotype, the development of Th17-dependent immune response seems to result from a durable systemic persistent inflammation.The views on the key role of Th1/Th2 balance in the development of asthma are accomplished by evidence of Th17 lymphocyte involvement into the process, and Th1/Th17, Th2/Th17 phenotypes seem to be the polar features of the disease. Estimation of intensity and phenotype of inflammation in BA will permit a more objective evaluation of the therapy applied, and to choose further management strategies.