[Blood culture for diagnosing juvenile chronic myeloid leukemia; relationship to neurofibromatosis].

: During the past 12 years we studied children with unexplained chronic leukocytosis and other findings suggestive of acute or chronic myeloid leukemia (AML; CML). We used cultures in soft agar of peripheral blood for granulocyte-macrophage colony-forming cell (GM-CFC) analysis. Colonies were counted, examined morphologically and cytochemically and the findings in patients were compared with those in normal children and patients with leukemoid reactions. 2 children with confirmed CML and neurofibromatosis (NF) were similarly evaluated. Additional studies in 1 of them and in his mother who had NF, included establishment of fibroblast and blood cultures from affected skin and tumor, and stimulation of normal bone marrow-derived GM-CFC by these fibroblasts and the conditioned medium (CM) from these cultures. Growth of GM-CFC from blood cultures of CML and AML patients was significantly enhanced in comparison with blood cultures from normal donors, or patients with other myeloproliferative disorders or leukemoid reactions. Enhanced GM-CFC growth-supportive activity was obtained from CML-NF skin and tumor culture CM in comparison with CM from normal fibroblasts. These results indicate the diagnostic value of blood culture GM-CFC in juvenile CML, and its usefulness in differentiating between CML and other disorders involving leukocytosis. They suggest a possible connection between NF foci and the enhanced proliferation of blood GM-CFC in CML.