FIP1L1/PDGFR -Associated Systemic Mastocytosis

Since the identification of the FIP1L1/PDGFRA fusion gene as a pathogenic cause of the hypereosinophilic syndrome (HES), the importance of the molecular classification of HES leading to the diagnosis of chronic eosinophilic leukemia (CEL) has been recognized. As a result, a new category, ‘myeloid and lymphoid neoplasm with eosinophilia and abnormalities in PDGFRA, PDGFRB or FGFR1’, has recently been added to the new WHO criteria for myeloid neoplasms. FIP1L1/PDGFR  -positive disorders are characterized by clonal hypereosinophilia, multiple organ dysfunctions due to eosinophil infiltration, systemic mastocytosis (SM) and a dramatic response to treatment with imatinib mesylate. A murine HES/CEL model by the introduction of FIP1L1/PDGFR and IL-5 overexpression also shows SM, representing patients with FIP1L1/PDGFR  -positive HES/CEL/SM. The murine model and the in vitro development system of FIP1L1/ PDGFR -positive mast cells revealed the interaction between FIP1L1/PDGFR  , IL-5 and stem cell factor in the develPublished online: June 4, 2010 Correspondence to: Dr. Yoshiyuki Yamada Division of Allergy and Immunology Gunma Children’s Medical Center 779 Shimohakoda, Hokkitsu, Shibukawa, Gunma 377-8577 (Japan) Tel. +81 279 52 3551, Fax +81 279 52 2045, E-Mail yamaday @ gcmc.pref.gunma.jp © 2010 S. Karger AG, Basel Accessible online at: www.karger.com/iaa D ow nl oa de d by : 54 .7 0. 40 .1 1 10 /2 1/ 20 17 2 :5 0: 07 A M