Morphology of a pure hematogone population isolated from normal and hematogone-rich bone marrow

B-ceLL precursors (hematogones) account for Less than 5% of normaL bone marrow (BM) nucLeated ceUs but in some cLinicaL conditions the number of hematogones can be transientLy increased. Their morphoLogy has been characterized in patients with increased numbers of hematogones. However, the scarcity of hematogones and inabiLity to obtain their pure popuLation make it difficuLt to thoroughLy investigate the morphoLogy of these ceLLs in normaL BM. A pure popuLation of hematogones was isoLated as a fraction of CD10+ BM mononucLear ceLLs from 14 patients with increased numbers of hematogones and 12 heaLthy donors using microarrays with immobiLized antibodies to duster of differentiation (CD) antigens. We described the main morphoLogicaL subtypes of hematogones of normaL BM and anaLyzed the proportion of these ceUs among CD19+, CD22+, CD20+, and CD10+CD34+ BM mononucLear ceUs. One to nine percent of hematogones are 13-17 mm in diameter and have basophiLic cytopLasm, Lacy or fineLy reticuLated, bLastic chromatin and prominent nucLeoLi. The remaining hematogones are immature Lymphoid ceLLs that vary considerabLy in size (7-15 mm in diameter) and have scanty cytopLasm, smudged chromatin and absent nucLeoLi. Three to twenty-five percent of these ceLLs are Larger than 10 mm. CD10+CD34+ ceLLs do not show predominancy bLastic morphoLogy, however some bLast-Like hematogones express CD20. Hematogones in normaL BM are heterogeneous in morphoLogy and size. We found no apparent correLation between the morphoLogy of hematogones and their stages of maturation. The study was approved by the Independent Ethics Committee and the Scientific CounciL of the Dmitry Rogachev NationaL MedicaL Research Center of Pediatric HematoLogy, OncoLogy and ImmunoLogy of Ministry of HeaLthcare of the Russian Federation. ALL donors and patients gave their informed consent to BM aspiration and participation in future biomedicaL studies.