Contributions
Type: Publication Only
Background
Hypereosinophilias comprise a very heterogenous group of haematologic alterations. They are usually secondary to diseases affecting various organ systems, although they may also have clonal or idiopathic aetiologies. The differential diagnosis is crucial and has significant implications that affect the therapeutic decision. According to the World Health Organization Classification (WHO) 2008, clonal hypereosinophilias are included in lymphoid and myeloid neoplasms associated with eosinophilia and platelet-derived growth factor receptor alfa (PDGFRA), platelet-derived growth factor receptor beta (PDGFRB) or fibroblast growth factor receptor 1 (FGFR1) abnormalities. Screening for rearrangements of these genes to document clonal eosinophilias, in which the tyrosine kinase inhibitor Imatinib has demonstrated effectiveness as a first-line agent, is fundamental since the treatment of reactive hypereosinophilias and idiopathic Hypereosinophilic Syndrome (HS) is, respectively, that of the underlying condition and systemic corticosteroids.
Aims
Analysis of patients with peripheral blood (PB) or bone marrow (BM) hypereosinophilia screened for PDGFRA and PDGFRB gene rearrangements and evaluation of response to treatment.
Methods
Retrospective analysis of patients with PB (>1500/uL) or BM (>5%) hypereosinophilia screened for PDGFRA and PDGFRB gene rearrangements, between 2008 and 2014.
Results
PDGFRA and PDGFRB gene rearrangements were screened in 23 patients with hypereosinophilia: of these 12 had secondary aetiologies and 11 were primary. Of the secondary eosinophilias, 4 were due to parasitic infestation, 4 allergic, 2 lung diseases, 1 systemic mastocytosis and 1 T cell lymphoma. Of the primary eosinophilias (11): 4 patients had PDGFRA rearrangements, 2 of them associated with T-ALL; 2 had PDGFRB rearrangements; 3 had HS; 1 had chronic eosinophilic leukemia and 1 myeloproliferative neoplasm. Out of the 6 patients with PDGFRA or PDGFRB rearrangements, 1 died before starting treatment, 1 had no criteria for therapy iniciation and all 4 treated with Imatinib (100-400mg/day) had good tolerance and hematologic response with 2 achieving molecular response. The median eosinophil count at presentation was 1780/uL (Q1 382.5; Q2 1787.5).
Summary
Our data is in agreement with the literature regarding the incidence of primary hypereosinophilias and the therapeutic efficacy of Imatinib, with response rates >80%.
Disclosure of Interest: none declared
Keyword(s): Eosinophilia, Hypereosinophilic syndrome, Imatinib
Session topic: Publication Only
Type: Publication Only
Background
Hypereosinophilias comprise a very heterogenous group of haematologic alterations. They are usually secondary to diseases affecting various organ systems, although they may also have clonal or idiopathic aetiologies. The differential diagnosis is crucial and has significant implications that affect the therapeutic decision. According to the World Health Organization Classification (WHO) 2008, clonal hypereosinophilias are included in lymphoid and myeloid neoplasms associated with eosinophilia and platelet-derived growth factor receptor alfa (PDGFRA), platelet-derived growth factor receptor beta (PDGFRB) or fibroblast growth factor receptor 1 (FGFR1) abnormalities. Screening for rearrangements of these genes to document clonal eosinophilias, in which the tyrosine kinase inhibitor Imatinib has demonstrated effectiveness as a first-line agent, is fundamental since the treatment of reactive hypereosinophilias and idiopathic Hypereosinophilic Syndrome (HS) is, respectively, that of the underlying condition and systemic corticosteroids.
Aims
Analysis of patients with peripheral blood (PB) or bone marrow (BM) hypereosinophilia screened for PDGFRA and PDGFRB gene rearrangements and evaluation of response to treatment.
Methods
Retrospective analysis of patients with PB (>1500/uL) or BM (>5%) hypereosinophilia screened for PDGFRA and PDGFRB gene rearrangements, between 2008 and 2014.
Results
PDGFRA and PDGFRB gene rearrangements were screened in 23 patients with hypereosinophilia: of these 12 had secondary aetiologies and 11 were primary. Of the secondary eosinophilias, 4 were due to parasitic infestation, 4 allergic, 2 lung diseases, 1 systemic mastocytosis and 1 T cell lymphoma. Of the primary eosinophilias (11): 4 patients had PDGFRA rearrangements, 2 of them associated with T-ALL; 2 had PDGFRB rearrangements; 3 had HS; 1 had chronic eosinophilic leukemia and 1 myeloproliferative neoplasm. Out of the 6 patients with PDGFRA or PDGFRB rearrangements, 1 died before starting treatment, 1 had no criteria for therapy iniciation and all 4 treated with Imatinib (100-400mg/day) had good tolerance and hematologic response with 2 achieving molecular response. The median eosinophil count at presentation was 1780/uL (Q1 382.5; Q2 1787.5).
Summary
Our data is in agreement with the literature regarding the incidence of primary hypereosinophilias and the therapeutic efficacy of Imatinib, with response rates >80%.
Disclosure of Interest: none declared
Keyword(s): Eosinophilia, Hypereosinophilic syndrome, Imatinib
Session topic: Publication Only