title: Clinical correlates of serum pro-major basic protein in a spectrum of eosinophilic disorders and myelofibrosis.
abstract: OBJECTIVE
  Eosinophil cytoplasmic granules contain major basic protein (MBP), which is primarily translated from its precursor, proMBP. In this study, we evaluated the plasma level of proMBP in eosinophilic and chronic myeloproliferative disorders (MPN).
  
  
  METHODS
  The levels of plasma proMBP were measured by radioimmunoassay in 25 healthy controls, 23 patients with systemic mastocytosis (SM), 11 patients with idiopathic eosinophilia (IE) and a cohort of 170 patients with MPN which included 76 patients with de novo myelofibrosis, 42 with polycythemia vera (PV), 17 with postpolycythemic myeloid metaplasia (Post-PV MF), 21 with essential thrombocythemia (ET) and 14 with postthrombocythemic myeloid metaplasia (Post-ET MF).
  
  
  RESULTS
  The plasma proMBP level was significantly higher in patients with SM with eosinophilia (p < 0.001), IE (p < 0.001) and MPN with eosinophilia (p = 0.002) than in healthy controls. The median proMBP level of Post-PV MF and Post-ET MF patients was significantly higher than in PV and ET patients (p < 0.001 and p = 0.009, respectively). In IE patients, elevated proMBP was significantly correlated with the presence of splenomegaly (p < 0.05). In 76 de novo myelofibrosis patients, the proMBP level was correlated with spleen size and the presence of hypercatabolic symptoms.
  
  
  CONCLUSIONS
  The significantly elevated levels of proMBP in myelofibrosis patients implies that proMBP could be an important stromal cytokine in bone marrow fibrosis.
authors.affiliation: Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, Minn., USA.
authors.forename: Ching-Liang
authors.initials: CL
authors.lastname: Ho
authors.forename: Hirohito
authors.initials: H
authors.lastname: Kito
authors.forename: Diane L
authors.initials: DL
authors.lastname: Squillace
authors.forename: Terra L
authors.initials: TL
authors.lastname: Lasho
authors.forename: Ayalew
authors.initials: A
authors.lastname: Tefferi
mesh_terms: D002908:Chronic Disease; D015331:Cohort Studies; D016207:Cytokines / Q000097:blood*; D047093:Eosinophil Major Basic Protein / Q000097:blood*; D004802:Eosinophilia / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D055728:Primary Myelofibrosis / Q000097:blood*; D011498:Protein Precursors / Q000097:blood*
chemical_list: D016207:Cytokines; D011498:Protein Precursors; D047093:Eosinophil Major Basic Protein