Influence of congenital heart disease-caused hypoxia on intrathymic development of t-lymphocytes in children of first year of life

Abstract

Aim. To study the influence of hypoxia, caused by congenital heart disease, on the intrathymic development of T-lymphocytes and provision of the organism with T-cellular resource in children with cardiac pathology of different degree of severity.
 Materials and methods. The paper presents the results of complex immunomorphological study of the thymus in children of the first year of life (n = 129) with congenital heart diseases. Hystochemical and immunological methods were used to assess the influence of congenital heart disease-caused hypoxia on the functional status of thymus regarding provision of a child with T-lymphocytes.
 Results. It was established that the degree of severity of congenital heart disease correlated with the degree of suppression of T-lymphocyte pool formation. During the first year of life, proliferative activity of thymocytes (assessed by Ki-67 expression) in the thymus falls, being the reason of decrease in the number of CD3+ thymocytes. In conditions of marked hypoxia (blue type of defect) the process of T-lymphocyte differentiation is inhibited that causes preservation of less mature forms of thymocytes. As a result, hypoxia is the reason of proliferation suppression and thymocyte differentiation, influencing subpopulation composition of the cells. Thus, insufficient quantity of thymic migrants enters the peripheral blood that confirms low functional activity of thymus regarding provision of the organism with T-cellular resource.
 Conclusions. No doubt, it can be the cause of immunodeficient state and reduced formation of adaptive immunity in this category of children.