Vol 15, No 4 (2016)

The objective. To study neutrophil Fc-gamma receptor expression and the possibility of its modulation in premature newborns with bacterial infection. Patients and methods. We examined samples of umbilical blood and also peripheral venous blood of newborns collected on the 28-30th day of life. The method of flow cytometry was used to detect the level of surface expression of neutrophil Fc-gamma receptors (CD64, CD32, CD16), phagocytic activity and oxidative burst of granulocytes stimulated by fluorescent labelled Escherichia coli. Results. Blood samples of 48 children were examined, of them 10 - full-term newborns (group 1), 18 - premature newborns with ELBW and VLBW (group 2), 20 - premature newborns with LBW (group 3). CD64 expression at birth in premature children from the 2nd and 3rd groups was 7.1 MFI (5.1; 11.5) and 6.0 MFI (5.3; 9.8), respectively, which is significantly higher (p = 0.013) than in children from group 1 (4.27 MFI (2.4; 5.8)). CD16 expression at birth was lower (p = 0.021) in premature children (group 2: 80.9 MFI (58.7; 114.8); group 3: 99.7 MFI (71.3; 126.0)) as compared with full-term newborns (125.3 MFI (95.5; 144.1)) and increased by the end of the 1st month of life (group 2: 118.5 MFI (99.5; 132.2); group 3: 126.6 MFI (110.1; 129.0)). Analysis of CD32 expression did not show statistically significant differences in the groups of study. A correlation between the intensity of oxidative burst of neutrophils and gestational age has been shown (Rs = 0.67; p = 0.0005). Granulocyte cultivation in the presence of G-CSF brings about a 2.4-5-fold increase of CD16, CD32 expression and enhanced oxidative burst. Conclusion. Premature newborns are characterised by dysregulation of Fc-gamma receptor expression and functional deficiency of neutrophils. G-CSF modulates CD16 and CD32 expression on the neutrophil surface and enhances oxidative burst.

Kasabach-Merritt syndrome (KMS) is a condition characterised by the presence of a vascular tumour, consumptive thrombocytopenia and coagulopathy. An impaired system of haemostasis results in development of disseminated intravascular coagulation syndrome. KMS is associated with Kaposiform haemangioendothelioma and «tufted» angioma. KMS is characterized by high lethality to 30% related to both haemorrhagic complications and invasive growth of tumour and its compression of vital structures. A search for an effective and safe method of management of KMS remains an urgent problem. In the past years, propranolol - a nonselective beta-blocker - is considered as one of potential therapeutic agents. The feasible mechanisms of action are considered to be vasoconstriction (including indirect suppression of expression of endothelial NO synthetase), suppression of VEGF (vascular endothelial growth factor) and bFGF (basic fibroblast growth factor) - induced proliferation of endothelial cells, induction of apoptosis, and also blockage of matrix metalloproteinases (ММPs) and IL-6 (proangiogenic cytokine). The effectiveness of propranolol has been proven only for treatment of infantile haemangiomas.

Acute lymphoblastic leukemia (ALL) is the most common malignant haematological disease of childhood. ALL is associated with the development of an immune defect, promoting development of both serious infectious complications at the initial stage of therapy and long-term persistent infections in patients during remission. The work studied naîve T and B cells in 49 children in the first acute period of ALL and 55 convalescent children at different terms of remission based on detection of T-cell receptor (TRECs) and K-deleting element (KRECs) excision circles by real-time PCR. As has been shown, development of ALL itself does not lead to suppression of naîve T- and B cell maturation. Specific therapy promotes development of a deep defect of both T and B cell immunity, deficit of naîve T cells persisting for not less than three years after statement of remission, whereas maturation of В cells is restored after termination of the intensive phase of therapy. Also, the inexpediency of using high dosages of methotrexate and cranial irradiation from the viewpoint of long-term immune reconstitution has been confirmed.

The work was aimed at analysis of the role of haemopoietic stem cell transplantation in treatment of acute myeloid leukemia in children. The study included 151 patients with de novo acute myeloid leukemia and 39 patients with relapsed. Patients with de novo acute myeloid leukemia received programme treatment in the Republican Research and Practical Centre of Paediatric Oncology, Haematology and Immunology of the city of Minsk in the period from May 1999 to December 2013 according to original protocols AML-ММ-2000 and AML-ММ-2006. Patients with relapsed acute myeloid leukemia received treatment according to the international protocol AML-Relapsed 2001/01. Our analysis has shown that allogenic haemopoietic stem cell transplantation is absolutely indicated to patients with prognostically unfavourable molecular-genetic abnormalities in first remission and to all patients receiving second-line treatment. Patients of a favourable prognostic group have good results of treatment even without haemopoietic stem cell transplantation in first remission.

Genetic studies of the last ten years have lead to dramatic changes in the concept of the biology of medulloblastomas. It is now accepted that there are four genetic (molecular) groups of medulloblastomas: WNT (Wingless), SHH (Sonic Hedgehog), group 3 and group 4. These groups are significantly different as far asgene expression, disease stateand prognosis are concerned. Adequate treatment, including the use of targeted drugs, now imperatively requires stratification according to the new criteria. This article provides a systematic review of relevant latest research on this new stratification of medulloblastomas.

FN-y is a cytokine of great clinical significance. The excessive or insufficient function of the signalling pathway triggered by IFN-y is a cause of various pathological states of the immune system and the body in general. At present, clinical practice uses quantitative methods of detection of this protein without taking into account its functional activity. Traditional tests for assessment of the biological activity of IFN-y are technologically complex and their results are poorly quantified. In the course of this work a model system was created representing a cell line with a reporter construct stably integrated into the genome controlled by a STAT-dependent promotor. Processing of the cells of this model system by IFN-y activates the STAT-1-signalling pathway, which causes expression of FFly luciferase gene. Luciferase activity is quantitatively assessed by detection of bioluminescence. Working concentration values (2.5 ng/ml) and time of performing the assay (8 h) were chosen. The effectiveness of using the model system for testing IFN-y bioactivity has been shown.