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HSPs demonstrate a strong association with gamma-delta (γδ) T cells. Most of the studies regarding interactions between the parameters were conducted in the 1990s. Despite promising results, the concept of targeting γδ T cells by HSPs seems to be a forgotten direction due to potent non-peptidic phosphoantigens rather than HSPs have been found to be the essential stimulatory components for human γδ cells. Currently, with greater knowledge of lymphocyte diversity, and more accurate diagnostic methods, we decided to study the correlation once again in the neoplastic condition. Twenty-one children with newly diagnosed acute lymphoblastic leukaemia (ALL) were enrolled on the study. Serum HSP90 concentrations were evaluated by an enzyme-linked immunosorbent assay (ELISA), subsets of γδ T cells (CD3+ γδ, CD3+ γδ HLA/DR+, CD4+ γδ and CD8+ γδ) by flow cytometry. We have shown statistically relevant correlations between serum HSP90 and CD3+ HLA/DR+ γδ T cells in paediatric ALL at diagnosis (R = 0.53, p &lt, 0.05), but not after induction chemotherapy. We also have demonstrated decreased levels of both serum HSP90 and CD3+ HLA/DR+ γδ T cells before treatment, which may indirectly indicate dose-dependent unknown interaction between the parameters. The results of our study may be a good introduction to research on the association between HSPs and CD3+ HLA/DR+ γδ T cells, which could be an interesting direction for the development of anti-cancer strategies, not just for childhood ALL.

Acute lymphoblastic leukemia (ALL) is the leading cause of cancer related death in children despite recent advances showing improved responses to chemotherapy treatment. Gamma-delta (γδ) T cells are a recent topic of growing interest in the field of adoptive immunotherapy. These cells have also been proven to be an optimal predictor of a favorable outcome in numerous malignancies. We evaluated subgroups of γδ T cells in the peripheral blood of 19 children with newly diagnosed ALL at the time of diagnosis and following chemotherapy induction. Due to the fact that serum HSP90 serves as a ligand for γδ T cells, we also checked the correlation between HSP90 and γδ T cells. As a result, we found, that the number of CD8+ γδ T cells in peripheral blood at disease presentation was almost three times higher in the intermediate risk group compared to patients in high risk group. Furthermore, we observed higher percentages of the subset in younger patients at diagnosis and after induction, but not in healthy controls. We also noticed negative correlations between CD8+ γδ T cells and minimal residual disease (MRD) before chemotherapy and after induction. We showed a positive association between activated CD3+ γδ T cell and serum HSP90 at presentation. In conclusion, our data suggests that CD8+ γδ T cells may be an early marker of favorable prognosis in childhood ALL while serum HSP90 may act as an agent activating CD3+ γδ T effector cells.

Regulatory T-cells (Tregs) are a very important subtype of lymphocytes when it comes to self-control in the human immunological system. Tregs are decisive not only in the protection against destruction of own tissues by autoimmune immunocompetent cells but also in the immunological answer to developing cancers. On the other hand, Tregs could be responsible for the progression of acute and chronic leukemias. In our study, we review publications available in the PUMED database concerning acute leukemia, with a particular emphasis on child’s leukemias. The percentage of regulatory T-lymphocytes in peripheral blood and bone marrow was elevated compared to those in healthy individuals and correlated with progressive disease. Regulatory T-cells taken from children diagnosed with leukemia showed a higher suppressive capability, which was confirmed by detecting elevated levels of secreted IL-10 and TGF-beta. The possibility of pharmacological intervention in the self-control of the immunological system is now under extensive investigation in many human cancers. Presumably, Treg cells could be a vital part of targeted therapies. Routine Treg determination could be used to assess the severity of disease and prognosis in children with acute lymphoblastic leukemia. This proposition results from the fact that in some studies, higher percentage of Treg cells in peripheral blood was demonstrated. However, observations confirming these facts are scarce; thus, extrapolating them to the population of children with hematological malignancies needs to be verified in additional studies.