In one female patient, the abnormal PML-RAR fusion gene was found only in the more mature CD34+/CD38+ cell fraction using a nested PCR approach, whereas the polyclonal CD34+/CD38- fraction was PML-RARA negative.     ///    These findings were confirmed in a third patient with APL in whom the PML-RARA transcripts were absent in the CD34+/CD38- cell fraction.     ///    Highly purified primitive hematopoietic stem cells are PML-RARA negative and generate nonclonal progenitors in acute promyelocytic leukemia.. 