CD4+CD25highCD127low/-FoxP3 + Regulatory T-Cell Population in Acute Leukemias: A Review of the Literature.

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.

CD4+CD25highCD127low/-FoxP3+ Regulatory T Cell Subpopulations in the Bone Marrow and Peripheral Blood of Children with ALL: Brief Report.

CD4+CD25highCD127low/-FoxP3+ regulatory T cells (Tregs) are currently under extensive investigation in childhood acute lymphoblastic leukemia (ALL) and in other human cancers. Usually, Treg cells maintain the immune cell homeostasis. This small subset of T cells has been, in fact, considered to be involved in the pathogenesis of autoimmune diseases and progression of acute and chronic leukemias. However, whether Treg dysregulation in CLL and ALL plays a key role or it rather represents a simple epiphenomenon is still a matter of debate. Treg cells have been proposed as a prognostic indicator of the clinical course of the disease and might also be used for targeted immune therapy. Our study revealed statistically higher percentage of Treg cells in the bone marrow than in peripheral blood in the group of 42 children with acute lymphoblastic leukemia. By analyzing Treg subpopulations, it was shown that only memory Tregs in contact with leukemic antigens showed statistically significant differences. We noticed a low negative correlation between Treg cells in the bone marrow and the percentage of blasts (R = -0.36) as well as a moderate correlation between Treg cells in the bone marrow and Hb level (R = +0.41) in peripheral blood before therapy. The number of peripheral blood blasts on day 8th correlates negatively (R = -0.36) with Tregs. Furthermore, statistical analysis revealed low negative correlation between the number of Tregs in the bone marrow and the minimal residual disease measured on day 15th, the percentage of blasts in the bone marrow and leukocytosis after 15 days of chemotherapy. These results indicate the influence of Tregs on the final therapeutic effect.

[Treatment regimen for children and adolescents with Hodgkin's disease designed to decrease late complications of radiotherapy]. / Program leczenia choroby hodgkina u dzieci i mlodziezy zmierzajacy do ograniczenia powiklan po radioterapii.

Between 1997 to 1999 in 9 centres of the Polish Paediatlic Leukemia/Lymphoma Study Group, 167 children and adolescents (aged 2-19 years) with stage 1 to IV Hodgkin's disease (HD) were treated according to a regimen with a limited use of radiotherapy (RT). All patients received B-DOPA and MVPP chemotherapy. The number of cycles of chemotherapy was adjusted in respective risk groups. In 13 children with stage IA and IIA disease with favourable prognostic factors chemotherapy alone was used. In other patients the dose of RT applied to lymphatic regions was 15-46,4 Gy. In case of a small tumour at presentation and good response to initial chemotherapy the RT dose was 15-16 Gy. In other cases doses of 25-30 Gy were planned. The use of higher doses, particularly exceeding 35 Gy, in eleven patients, was not justified. Among all the 167 patients, three oftliem (1.2%) with advanced disease (Stage III-1V) did not achieve first remission. The 4-year overall survival (OS), relapse free survival (RFS) and event free survival (EPS) were 99%. 93% and 90%, respectively. Relapses occurred in 8 children (first remission lasted for 4-29 (median = 9 months). All 13 children in whom chemotherapy alone was used remain in first remission. In the group of children who received RT in the dose of 15-16 Gy relapse occurred in one child. Our preliminary analysis indicates that limited use of RT in selected cases of HD in children and adolescents did not show worse results of treatment. However, the assessment of possible influence of this regimen on the decreased rate of late complications requires longer follow-up.

[Cardiotoxic complications in Wilms' tumour survivors after treatment with anthracyclines]. / Powiklania kardiotoksyczne u pacjentów z guzem Wilmsa leczonych antracyklinami.

The aim of the study was an evaluation of circulatory system functions in patients with Wilms' tumour who underwent the multidrug chemotherapy with anthracyclines. The investigation was carried out on 43 patients after chemotherapy between 1994-1997, from 4 centres of paediatric oncology (in Gdansk, Poznan, Lublin and Bydgoszcz). All patients were divided into two groups. The children from the first group received anthracyclines without Cardioxan protection. The patients from the second group had been treated with both anthracyclines and Cardioxan. The cardiotoxicity was estimated in relation to the total dose of anthracyclines. Comparing the side effects of chemotherapy in both groups there were no essential differences in bone marrow suppression and in hepatotoxic symptoms.