Immunological and biochemical changes in young children with recurrent course of respiratory infections and cytomegaloviral infection

Abstract

Cytomegalovirus (CMV) infection in practically healthy children of different ages ranges from 50% to 64%. Both acute course of infection and prolonged persistance of pathogen is accompanied by immune deficiency formation that may become one of factors in charge of high level of infection morbidity in future as recurrent respiratory infections (RRI). At the same time significant spread of deficiency states in infants - deficiency of iron ion or vitamin D - is also accompanied by changes in immunological reactivity, especially when combined with intracellular infections. Purpose of the work was to study some immune and biochemical changes in young children (n=37) with recurrent respiratory diseases and cytomegaloviral infection. Materials and methods. In 51 children the CMV infection was verificated by simultaneous detection of specific anti-CMV IgG and anti-CMV IgM in blood serum and viral DNA finding by polymerase chain reaction. The observation group consisted of 37 (72.5%) children infected with CMV as well as suffering from recurrent respiratory infections. Comparison group was represented by the remaining 14 (27.5%) patients with episodic respiratory infections (ERI). In RRI group the patients with the frequent respiratory diseases with bacterial implications four and more times during the second year of life were included. The levels of serum iron and 25-hydroxy-cholecalciferol (vitamine 25(ОН)D) were detected in blood serum of all children by ELECSYS-test. In the early convalescence period after respiratory infections comparative immunograms assessment was conducted by three main components: phagocytic activity of neutrophils, the system of cellular immunity and quality of humoral immunity. In the vast majority (72.5%) of the children age up to 1yo with verified CMV infection respiratory infections of viral and bacterial etiology gained a recurrent course (p <0.05). In the early convalescence period after respiratory infection process in children with CMV and RRI the immune response is characterized by a decreasing of the functional and metabolic activity of neutrophile granulocytes (р<0,05) and imbalance of humoral immunity consisting in decreased antibody generation (IgА (р<0,05), IgМ (р<0,05), tendency to IgG decreasing). These changes are compensated by the increasing of the total number of B-lymphocytes (р<0,05). We founded a significantly lower average level of 25-hydroxy-cholecalciferol (32,37|23,41-39,95|ng/ml) in children of the observation group. In the comparison group this rate was 44,21|35,38-52,82|ng/ml, р<0,05. We also detected a correlation dependence between concentration of vitamin 25(OH)D and antiCMV IgG (r = 0,35, p <0.05), decreased concentration of each of them is clinically manifested in pathogen persistence and recurrence course of respiratory infections in children. In the patients from observation group serum iron concentration was significantly lower than the corresponding data of those children who suffered from the respiratory diseases occasionally: 4,05|3,74-5,05| mcmol/l and 8,6|4,92-11,72| mcmol/l (р<0,05) respectively. There was a slight correlation dependence between serum iron level and blood anti-CMV IgG-antibodies level (r=0,28, р<0,05). So, the fact of the important role of iron ions in the mechanisms which regulate the functional activity of CD4+-cells was confirmed (r=0,49, р<0,05).