Features of Parameters of Cellular Immune Depending on the Activity of Foci of Demyelination in Children with Multiple Sclerosis

MS is a common disease of the central nervous system that leads to disability and reduced quality of life. The debut of disease in 3-5% of patients occurs in childhood and has a less favorable course compared to adults. MS is caused by the activation of autoreactive T cells in the breakdown of peripheral tolerance, which is normally controlled by regulatory T cells (Tregs). It is promising to study expression of CD39 and CD73 in Treg and Th17 populations to assess their suppressive activity. Aim is to evaluate content of major and minor lymphocyte populations and expression of CD39 and CD73 in CD4+ lymphocyte population in children with MS. 111 children with MS were examined, 66 with contrast-negative lesions on MRI (Group 1), 45 with contrast-positive lesions (Group 2). The comparison group consisted of 46 healthy children (Group 3). Content of T, B, NK lymphocytes, Treg (CD4+CD25highCD127low), Thact (CD4+CD25highCD127high), Th17 cells (CD3+CD4+CD161+); expression of CD39 and CD73 in Treg, Th17 and Thact was performed by flow cytometry. An increase in content of T helpers, a decrease in NK cells in patients in group 2 was revealed. An increase in number of Thact and Th17 lymphocytes was obtained in patients of both groups with MS. Number of Tregs in group 1 was significantly higher than in group 3. Ratio of cells expressing CD39 and CD73 in MS patients depended on lymphocyte population as well as in the group 3. The highest content of CD39+ cells was observed in Treg population, and the lowest in Thact population. For CD73 expression, on the contrary, the highest expression of CD73 was observed in Thact cells, the lowest in Treg. When comparing groups of patients, it was found that in patients of group 1, number of cells expressing CD39 ectonucleotidase was significantly increased, and number of supTh17 was comparable with group 3. In both groups of MS patients, an increase in CD73 counts in Treg, Thact and Th17 was observed. Thus, informative populations of lymphocytes (CD4+ cells, Treg, CD39+Treg, supTh17) have been identified, which can be used to monitor condition of children with multiple sclerosis.