title: Numbers of colony-forming progenitors in patients with systemic mastocytosis: potential diagnostic implications and comparison with myeloproliferative disorders.
abstract: BACKGROUND
  An increase in colony-forming progenitor cells (CFU) is typically seen in myeloproliferative disorders (MPD). Systemic mastocytosis (SM) is a haemopoietic neoplasm involving myeloid progenitors similar to MPD. In the present study, we measured the levels of peripheral blood (pb) and bone marrow (bm) CFU in patients with different categories of SM, and compared them with those obtained in MPD patients and healthy controls.
  
  
  METHODS
  Numbers of CFU (CFU-GM, BFU-E, CFU-GEMM) were measured in a colony assay in 25 patients with SM [indolent SM (ISM), n = 15; smouldering SM (SSM), n = 3; SM with an associated haematologic clonal non-mast cell lineage disease (SM-AHNMD), n = 5; aggressive SM (ASM), n = 1; mast cell leukaemia (MCL), n = 1] and 37 with MPD [chronic myeloid leukaemia (CML), n = 10; polycythemia vera (PV), n = 8; essential thrombocytosis (ET), n = 9; idiopathic myelofibrosis (IMF), n = 10].
  
  
  RESULTS
  In the patients with MPD, elevated numbers of pb CFU were detected in all groups when compared with healthy controls (P < 0.05). In most of the patients with ISM, circulating CFU levels (CFU-GM, BFU-E, and CFU-GEMM) were within the normal range. In SSM, pb CFU-GM levels were normal in two patients, and elevated in a third patient. In the "SM-AHNMD-group", CFU levels were found to reflect the nature of the AHNMD: in SM with concomitant acute myeloid leukaemia (SM-AML, n = 2), the levels of CFU were low or undetectable, whereas in SM with chronic myelomonocytic leukaemia (SM-CMML, n = 2), elevated numbers of pb CFU-GM were found.
  
  
  CONCLUSIONS
  The numbers of CFU are normal in patients with ISM, but elevated in some patients with SSM and SM-CMML. An elevated CFU level in SM should raise the suspicion of an associated MPD (CMML) or smouldering SM, a novel SM-subtype that shares several features with MPD and sometimes progresses to an overt SM-MPD.
authors.affiliation: Department of Internal Medicine I, Division of Hematology and Hemostaseology, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
authors.forename: J-H
authors.initials: JH
authors.lastname: Jordan
authors.forename: E
authors.initials: E
authors.lastname: Jäger
authors.forename: W R
authors.initials: WR
authors.lastname: Sperr
authors.forename: I
authors.initials: I
authors.lastname: Schwarzinger
authors.forename: M
authors.initials: M
authors.lastname: Födinger
authors.forename: R
authors.initials: R
authors.lastname: Fritsche-Polanz
authors.forename: L
authors.initials: L
authors.lastname: Ohler
authors.forename: K
authors.initials: K
authors.lastname: Geissler
authors.forename: P
authors.initials: P
authors.lastname: Valent
mesh_terms: D000328:Adult; D000368:Aged; D001854:Bone Marrow Cells / Q000473:pathology*; D002452:Cell Count / Q000379:methods; D003114:Colony-Forming Units Assay; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008407:Mast Cells / Q000473:pathology; D008415:Mastocytosis / Q000097:blood* / Q000175:diagnosis; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000097:blood / Q000175:diagnosis*; D013234:Stem Cells / Q000473:pathology