Thrombocytopenia with absent radii: Frequency of marrow megakarycyte progenitors, proliferative characteristics, and megakaryocyte growth and development factor responsiveness Academic Article uri icon


MeSH Major

  • Bone Marrow Cells
  • Hematopoietic Stem Cells
  • Megakaryocytes
  • Radius
  • Thrombocytopenia
  • Thrombopoietin


  • Congenital thrombocytopenia with absent radii (TAR syndrome) is characterized by defective thrombopoiesis and bleeding in early infancy. To determine the frequency and responsiveness to cytokines of megakaryocyte progenitors (CFU-Meg) in TAR syndrome, the authors studied marrow samples from 3 patients and 6 normal controls, using optimally standardized megakaryocyte growth media incorporating interleukin-3, interleukin-6, stem cell factor, and granulocyte-monocyte colony-stimulating factor, with and without pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF). CFU-Meg was identified with a specific staining system utilizing monoclonal antibodies to glycoprotein IIb/IIIa. Growth of small CFU-Meg colonies (3-20 cells/colony) was observed in all patients in cultures without PEG-rHuMGDF, with a mean frequency of 8 (range 5-12) per 2.25 x 10(5) mononuclear cells plated (control mean 23; range 2-70). Identical cultures of marrow cells from patients and controls with added PEG-rHuMGDF produced more colonies per dish (mean 17, range 8-23; control mean 30, range 6-62). Except for 1 case, however, patients' colonies in response to PEG-rHuMGDF remained smaller than those of controls. Two patients tested had higher plasma thrombopoietin levels than 6 normal subjects. The findings demonstrate proliferative and PEG-rHuMGDF-responsive megakaryocytic progenitors in TAR syndrome. The modest reduction in frequency of megakaryocyte progenitors and the suboptimal size of colonies in response to PEG-rHuMGDF are compatible with the reported defective signal transduction in the c-mpl pathway in TAR syndrome.

publication date

  • June 2000



  • Academic Article



  • eng

PubMed ID

  • 10845228

Additional Document Info

start page

  • 299

end page

  • 306


  • 17


  • 4