1. Blood CD34−c-Kit+ cell rate correlates with aggressive forms of systemic mastocytosis and behaves like a mast cell precursor
by Sophie Georgin-Lavialle, Ludovic Lhermitte, Cédric Baude, Stéphane Barete, Julie Bruneau, Jean-Marie Launay, Marie-Olivia Chandesris, Katia Hanssens, Christian de Gennes, Gandhi Damaj, Fanny Lanternier, Mohamed Hamidou, Olivier Lortholary, Patrice Dubreuil, Frédéric Feger, Yves Lepelletier, and Olivier Hermine
Blood
Volume 118(19):
November 10, 2011
©2011 by American Society of Hematology

2. Clinical applications of circulating CD34− c-Kit+ population rate.
Clinical applications of circulating CD34− c-Kit+ population rate. (A-B) Correlation of Valent stage disease with the rate of circulating CD34−c-Kit+ population and the rate of serum tryptase. (A) The rate of the circulating CD34−c-Kit+ is shown for each patient along with disease stage, indicating the aggressiveness of their disease, and compared with healthy controls. All mastocytosis patients with systemic forms had a significantly higher rate of CD34−c-Kit+ cells than the controls: ISM (P = .0007), ASM (P = .0031), and SM-AHNMD (P = .0005). This association was not found for cutaneous forms, which were comparable with the healthy controls (P = .5). (B) The serum rate of tryptase was always elevated among patients with mastocytosis, independently from the stage of the disease: cutaneous as well as systemic forms had an elevated serum tryptase. Indeed, serum tryptase levels among controls were always lower than patients with CM (P = .0385), ISM (P = .0242), ASM (P = .0005), or SM-AHNMD (P = .0012). (C-E) Clinical and biologic follow-up of 3 patients with aggressive systemic mastocytosis until death. (C) Patient 42. (D) Patient 32. (E) Patient 38. The clinical evolution and treatment are mentioned as well as the rate of the circulating CD34−c-Kit+ population. It shows that, when patients present aggressive disease with massive mast cell infiltration, the rate of the circulating CD34−c-Kit+ population is a good tool to quickly follow (within hours) the clinical evolution of the disease and to determine the efficiency of the treatments. CT indicates healthy control; 2CDA, Leustatin, Zenapax, daclizumab; and C1 to C4, cure number.
Sophie Georgin-Lavialle et al. Blood 2011;118:
©2011 by American Society of Hematology

3. Cytologic aspects (May-Grünwald-Giemsa smears) and histamine production of isolated CD34+/−c-Kit+/− compartments from PB of patients with mastocytosis and healthy controls.
Cytologic aspects (May-Grünwald-Giemsa smears) and histamine production of isolated CD34+/−c-Kit+/− compartments from PB of patients with mastocytosis and healthy controls. (A) Among healthy donors, cultures of both CD34+c-Kit+ and CD34−c-Kit+ cell subsets showed differentiation into mature mast cells in the presence of SCF (top panel), whereas no differentiation was observed in the absence of SCF (data not shown). In patients with proven mastocytosis, bearing either the classic D816V c-Kit mutation or WT c-Kit, similar differentiation into mature mast cells was observed in the presence or absence of SCF (bottom panel). (B) Histamine dosage also supported mast cell differentiation, demonstrating increased histamine levels with or without SCF in both cultured subsets from the patients with mastocytosis, whereas among healthy controls, histamine levels increased only in the presence of SCF.
Sophie Georgin-Lavialle et al. Blood 2011;118:
©2011 by American Society of Hematology