title: Bone marrow tryptase as a possible diagnostic criterion for adult systemic mastocytosis.
abstract: BACKGROUND
  Mastocytosis is difficult to diagnose, especially when systemic mast cell activation symptoms are not present or involve only one extracutaneous organ.
  
  
  OBJECTIVE
  The main objective was to evaluate the accuracy of the bone marrow tryptase level in the diagnosis of systemic mastocytosis in patients with a clinical suspicion of mastocytosis.
  
  
  METHODS
  We included all adult patients evaluated in our centre between December 2009 and 2013 for suspected mastocytosis as part of a standardized procedure and who had a bone marrow and serum tryptase assay on the same day. The diagnosis of systemic mastocytosis was established on the basis of the World Health Organization criteria as the gold standard. The accuracy of the bone marrow tryptase level in the diagnosis of systemic mastocytosis was assessed by a receiver operating characteristics curve analysis. The different sensitivity and specificity values, corresponding to the set of possible bone marrow tryptase level cut-off values, were estimated with 95% confidence intervals.
  
  
  RESULTS
  Seventy-three patients were included. The diagnosis of systemic mastocytosis was established in 43 patients (58.9%). The median bone marrow tryptase level was 423 μg/L [95% CI: 217-868] in the systemic mastocytosis group and 7.5 μg/L [95% CI: 4.6-17.1] in the non-systemic mastocytosis group (P < 0.001). A cut-off value of 50 μg/L for bone marrow tryptase identified systemic mastocytosis with a sensitivity of 93.0% [95% CI: 80.9-98.5%] and a specificity of 90.0% [95% CI: 73.5-97.9%].
  
  
  CONCLUSIONS
  The bone marrow tryptase level appears to be a valuable diagnostic criterion for confirming systemic mastocytosis. If this diagnosis can reliably be excluded by evaluation of the bone marrow tryptase level, there would be no need to perform a bone marrow biopsy.
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Dermatology, Paul Sabatier University, Toulouse University Hospital, Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Bulai Livideanu
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Immunology Clinical Laboratory, Toulouse University Hospital, Toulouse, France.
authors.forename: P A
authors.initials: PA
authors.lastname: Apoil
authors.affiliation: USMR Support Unit for Research Methodology, Department of Epidemiology, Toulouse University Hospital, Toulouse, France.
authors.forename: B
authors.initials: B
authors.lastname: Lepage
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Rheumatology, Toulouse University Hospital, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Eischen
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Anatomy and Pathological Cytology of Prof. Brousset, Cancer University Institute of Toulouse Oncopole, Toulouse 6 Paul Sabatier University, Toulouse University Hospital, Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Laurent
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Hematology Clinical Laboratory, Toulouse University Hospital, Toulouse, France.
authors.forename: P
authors.initials: P
authors.lastname: Laharrague
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Anatomy and Pathological Cytology of Prof. Brousset, Cancer University Institute of Toulouse Oncopole, Toulouse 6 Paul Sabatier University, Toulouse University Hospital, Toulouse, France.
authors.forename: L
authors.initials: L
authors.lastname: Lamant
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Anatomy and Pathological Cytology of Prof. Brousset, Cancer University Institute of Toulouse Oncopole, Toulouse 6 Paul Sabatier University, Toulouse University Hospital, Toulouse, France.
authors.forename: E
authors.initials: E
authors.lastname: Tournier
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Hematology, Toulouse University Institute of Cancer-Oncopole, Toulouse, France.
authors.forename: S
authors.initials: S
authors.lastname: Tavitian
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Dermatology, Paul Sabatier University, Toulouse University Hospital, Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Pouplard
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Hematology, Toulouse University Institute of Cancer-Oncopole, Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Recher
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Rheumatology, Toulouse University Hospital, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Laroche
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Pneumo-allergology, Toulouse University Hospital, Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Mailhol
authors.affiliation: CRCM, [Signaling, Hematopoiesis and Mechanism of Oncogenesis], Inserm, U1068, Marseille, France.|Institut Paoli-Calmettes; Aix-Marseille University, UM105, CNRS, UMR7258, Marseille, France.
authors.forename: P
authors.initials: P
authors.lastname: Dubreuil
authors.affiliation: CEREMAST, Department of Hematology, Necker Hospital, Paris-APH, Paris, France.
authors.forename: O
authors.initials: O
authors.lastname: Hermine
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Immunology Clinical Laboratory, Toulouse University Hospital, Toulouse, France.
authors.forename: A
authors.initials: A
authors.lastname: Blancher
authors.affiliation: Mastocytosis Expert Center of Midi-Pyrénées, Department of Dermatology, Paul Sabatier University, Toulouse University Hospital, Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Paul
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers; D001706:Biopsy; D001853:Bone Marrow / Q000201:enzymology* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D034721:Mastocytosis, Systemic / Q000175:diagnosis* / Q000201:enzymology*; D008875:Middle Aged; D012372:ROC Curve; D015203:Reproducibility of Results; D053802:Tryptases / Q000097:blood / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D053802:Tryptases
keywords: bone marrow tryptase; diagnostic; diagnostic criterion; mastocytosis; systemic mastocytosis; tryptase