PB1858 THE RESULTS OF THE COLONY‐FORMING ABILITY‘S DETERMINATION OF THE BONE MARROW IN CHILDREN WITH NEUTROPENIA
Authors: K. Vetoshkin, O. Tselousova, M. Butolina
Journal: HemaSphere (2019)

Background: Primary neutropenia is a rare hematological condition, mostly common in childhood. Neutropenic syndrome is heterogenous and may be a consequence of myelopoietic disorder in bone marrow, redistribution of neutrophils between the wall and circulating cell pools, enhanced destruction of granulocytes, and combination of these mechanisms. In this regard, the options for neutropenic conditions in children are very numerous. Determination of the pathogenetic mechanism of the development of neutropenia is possible only with a deep laboratory examination and is necessary to determine the tactics of patient‘s management. A cultural method of bone marrow's colony‐forming ability‘s assessing is one of the modern diagnostic approaches for cytopenias. Aims: Assessment the significance of the results of the bone marrow colony‐forming ability‘s determining at primary neutropenia in children. Methods: The results of laboratory tests of 10 patients examined for neutropenia were analyzed. The criterion of the diagnosis was considered an absolute decrease in the number of neutrophils in children over the age of 1 year ‐ less than 1,5 thousand in 1 μl of blood. The median of the age of patients was 9.5 (2.5‐17), among them there were 7 boys and 3 girls. To exclude system blood diseases, standard cytological and cytogenetic studies of the bone marrow were performed. The determination of the proliferative potential and differentiation capacity of the bone marrow was carried out by counting the number of granulocyte‐marcophagal‐erythrocyte‐megakaryocytic (CFU‐GEMM, normal 0‐8), granulocyte (CFU‐G, normal 7‐35), macrophage (CFU‐M, normal 1 ‐18), eosinophilic (CFU‐Eoz, norm 0‐22) and erythroid colonies (CFU‐Er, normal 20‐74) in a 14‐day culture. For this purpose, 0.2‐0.4 x 10 5 myelokaryocytes were introduced into the methylcellulose‐based medium (MethoCult H, StemCell Technologies). The number of formed colonies was considered as equal to the quantity of the corresponding colony‐forming units in the analyzed sample. Results: At the time of the examination, the number of leukocytes in the peripheral blood was 3.4 ± 1.3x10 3 /μl, and the absolute neutrophil content was 969 ± 871.3/μl. Depending on the results of the bone marrow‘s colony‐forming ability patients were divided into 2 groups ‐ with normal and reduced CFU‐G content. In 7 out of 10 patients with neutropenia, a reduced content of granulocyte progenitor cells in the bone marrow was detected: the number of CFU‐G was 2‐6, the number of the remaining CFU was in the normal range (CFU‐GEMM ‐ 0‐5, CFU‐M ‐ 11‐40, CFU‐Er 3‐56, CFU‐Eoz 0‐15). The lowest absolute neutrophil content per unit of peripheral blood‘s volume (170‐1325 in 1 μl, median ‐ 920) was recorded at patients of this group. In case of dynamic observation, infectious complications of various localization and severity were registered, which, along with antibacterial drugs, required the administration of a granulocyte colony‐stimulating factor (G‐CSF). The use of G‐CSF was accompanied by a pronounced positive effect. In the remaining cases (3 out of 10 patients), the bone‐marrow colony‐forming ability was within the normal range (CFU‐G ‐ 12‐36, CFU‐M ‐ 18‐46, CFU‐Er ‐ 10‐56, CFU‐Eoz ‐ 2 ‐ 5). In the peripheral blood of these patients the absolute number of neutrophils was moderately reduced (1000‐1840 in 1 μl, median ‐ 1650). Upon further observation of this patients, indications for G‐CSF and severe infectious diseases were not observed. Summary/Conclusion: Assessment of the results of bone marrow‘s cultural research allows to predict primary neutropenia‘s course and administrate pathogenic therapy.