FLUORESCENCE IN-SITU HYBRIDIZATION OF PROGENITOR CELLS OBTAINED BY FLUORESCENCE-ACTIVATED CELL SORTING FOR THE DETECTION OF CELLS AFFECTED BY CHROMOSOME ABNORMALITY TRISOMY-8 IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES

Myeiodysplastic syndrome (MDS) is believed to be a stem-cell disorder involving cytopenia and dysplastic changes in three hematopoietic line ages. However, the involvement of pluripotent stem cells and progenito r cells has not been clarified conclusively. To address this issue, we used fluorescence in situ hybridization (FISH) of blood and bone marr ow (BM) smears for mature cells and FISH of cells sorted by fluorescen ce-activated cell sorting for progenitor cells. Seven patients with MD s associated with trisomy 8 were studied. FISH showed +8 in granulocyt es, monocytes, and erythroblasts, but not in lymphocytes. Sorted cells of T (CD3(+)), 8 (CD19(+)), and NK cells (CD3(-)CD56(+)) from periphe ral blood did not contain +8, nor did CD34(+) subpopulations from EM i ncluding B (CD34(+)CD19(+)), T/NK (CD34(+)CD7(+)) progenitors, and plu ripotent stem cells (CD34(+)Thy1(+)). The ts chromosome abnormality wa s identified in stem cells only at the level of colony-forming unit of granulocyte-erythrocyto-macrophage-megakaryocyte (CFU-GEMM; CD34(+)CD 33(+)). It may thus be concluded that cells affected by trisomy 8 in t he context of MDS are at the CFU-GEMM level and that cells of lymphoid lineage are not involved. These results provide new insights into the biology of MDS and suggest that intensive chemotherapy and autologous BM transplantation may become important therapeutic strategies. (C) 1 998 by The American Society of Hematology.