title: Lack of circulating megakaryoblasts in newborn peripheral blood: development and validation of a sensitive flow cytometric detection method.
abstract: It is currently thought that approximately 1% of children with Down syndrome will develop a "premalignant" syndrome known as transient myeloproliferative disorder (TMD). Prospective, population-based studies of the incidence of TMD in Down syndrome infants is lacking. Although most cases of TMD resolve by 1 year of age, data suggest that 10% to 20% of Down syndrome patients with TMD develop AML-M7 (megakaryoblastic leukemia). To identify the true incidence of TMD in the Down syndrome population, a sensitive, rapid, and cost-effective method of quantifying circulating megakaryoblasts in large numbers of patients was needed. In this pilot study, the authors tested the hypothesis that there are fewer than 1% megakaryoblasts of nucleated cells circulating in the blood of normosomic infants. Four-antigen flow cytometry was used to establish the percentage of megakaryoblasts present in each of 100 cord blood samples collected blindly from "normosomic" live births. There was a mean percentage of 0.017% megakaryoblasts in 100 cord blood samples from normosomic infants. Flow cytometry proved to be a sensitive, rapid, and reproducible method for the quantification of megakaryoblasts. Less than 1% of circulating nucleated cells in the blood of newborn infants are megakaryoblasts, providing a comparison population for the authors' larger proposed incidence study.
authors.affiliation: Department of Pediatrics, University of Kentucky School of Medicine, Lexington, KY 40536-0284, USA. sbay12@pop.uky.edu
authors.forename: Sherry
authors.initials: S
authors.lastname: Bayliff
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Horvatinovich
authors.forename: Jerald Z
authors.initials: JZ
authors.lastname: Gong
authors.forename: Philip M
authors.initials: PM
authors.lastname: Rosoff
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis; D004314:Down Syndrome / Q000097:blood / Q000150:complications; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry / Q000379:methods*; D006412:Hematopoietic Stem Cells; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn / Q000097:blood*; D008533:Megakaryocytes / Q000166:cytology*; D009196:Myeloproliferative Disorders / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D010865:Pilot Projects; D011289:Preleukemia / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D018952:Antigens, CD34