State of erythroid, granulocyte and platelet branches of hematopoiesis on stages of chemotherapy in children with acute lymphoblastic leukemia, who were exposed to ionizing radiation after the Chornobyl NPP accident. / STAN ERYTROÏDNOÏ, GRANULOTsYTARNOÏ I TROMBOTsYTARNOÏ LANOK GEMOPOEZU NA ETAPAKh KhIMIOTERAPIÏ U DITEY̆ Z GOSTRYMY LIMFOBLASTNYMY LEY̆KEMIIaMY, IaKI ZAZNALY VPLYVU IONIZUIuChOGO VYPROMINIuVANNIa VNASLIDOK AVARIÏ NA ChAES.

OBJECTIVE: Evaluation of proliferation and differentiation processes of progenitor cells in bone marrow by the com position of elements of erythroid, granulocyte and platelet branches of hematopoiesis on the treatment stages in children with acute lymphoblastic leukemia (ALL), who were exposed to radiation from the Chornobyl NPP accident. MATERIALS AND METHODS: The 46 children with ALL were studied, who lived in Kyiv, Zhytomyr and Chernihiv regions. Studies were conducted before the start of chemotherapy (ChT), on the 33 day of ChT (phase I), and after the com pletion of ChT (phase II). Exposure doses of patients, hemogram and myelogram parameters both with indices of mat uration of progenitor cells were evaluated. Signs of dysplasia of hematopoietic branch elements were revewed. RESULTS: The 46 patients were studied. They have had the B ALL, namely pro B ALL (n=5), «common type¼ (n=36), pre B ALL (n=3), and T ALL in 2 other cases. In a debut of ALL the bone marrow was represented by lymphoblasts. Along with ChT conduction the bone marrow hematopoiesis recovered by such types, as erythroid, granulocyte, gran ulocyte whith monocytes, and uniform, when the cells number of all branches was within a normal quantity. At the phase ІІ of ChT the number of patients with hematopoiesis recovery by erythroid type decreased and number of chil dren with activation of granulocyte branch of hematopoiesis increased. In children with pro B ALL the number of erythroid elements was higher than normative at both ChT phases. A direct correlation was established between the number of myelokaryocytes (Mkc) and megakaryocytes (Mgkc) in both phase І and phase ІІ of treatment (Rs = +0.72; Rs = +0.56, respectively). There was no correlation between the radiation dose in patients (3.73 ± 0.12 mSv) and studied parameters. CONCLUSIONS: Types of bone marrow recovery were established in ALL patients after the ChT indicating to the differ ent kinetic pathways of hematopoietic progenitor cells. Evaluation of reasons of prevalence of some hematopoietic branches will allow to reveal their role in leukemogenesis and to correct the treatment programs.