[Regulatory T cells in children with acute lymphoblastic leukaemia]

There is a rising interest in the field of immunotherapy in cancer in the last few years. One of the methods is to prevent the immunosuppression accompanying neoplastic diseases including acute lymphoblastic leukaemia (ALL) in children. In healthy people regulatory T cells (Tregs) prevent the autoimmune, destructive activation of T lymphocytes. However, the hyperfunction of Tregs will lead to impairement of the immune system.

of our study was to determine the Tregs (including molecules important for their function) in the peripheral blood of children with ALL.

Thirty children were enrolled into our study, the assessment of Tregs was performed with flow cytometry including the following antigens: CD4, CD10, CD19, CD25, CD28, CD45, CD45RA, CD45RO, CD54 (ICAM-1), CD62L, CD69, CD103, CD127, CD134 (OX40), CD152 (CTLA-4), GITR.

1. The percentages of Tregs were higher in the blood of the examined group, however the difference was not statistically significant; 2. In the examined group higher percentage of Tregs with the coexpression of CD45RA, CD134 and CD152 antigens were noted; 3. The percentages of Tregs with coexpression of CD62L (with or without CD103) and CD54 were lower then in the control group; 4. We did not observe differences in Tregs with coexpression of CD11a, CD27, CD28, CD45RO, CD69, CD103, GITR antigens between the examined and the control group.

The finding of smaller number and lower percentage of regulatory T cells with coexpression of CD62L or lack expression of CD103 in children with ALL as compared to the control group, may be interpreted as activation of Treg cells and one of the mechanisms of immunosuppression in cancer of children. Further studies in this direction are needed.