Molecular characterization of paediatric idiopathic hypereosinophilia.

The hypereosinophilic syndromes (HES) include a group of heterogeneous diseases characterized by the persistent increase of the number of eosinophils in blood and bone marrow. Few cases of paediatric hypereosinophilia (pHES) have been described in the literature. Early identification of pHES that may evolve towards a lymphomyeloproliferative disease is relevant in light of prognostic and therapeutic implications. Molecular features of 10 pHES patients were analysed at presentation and during their clinical course, including analysis of BCR-ABL1 and FIP1L1/PDGFRA fusion genes, quantitation of WT1 gene copy number and clonality of T-cell receptor (TCR) and immunoglobulin heavy chain (IGH). All patients had normal karyotype and germline TCR configuration. Five children showed IGH clonality at presentation: of these, two developed a B non-Hodgkin lymphoma and a B-lineage acute lymphocytic leukaemia at six and 12 months respectively, two spontaneously reverted to a polyclonal IGH profile during the follow-up, and the last one persisted with pHES without B-clonal evolution after 19 months. One patient had a PDGFRA/FIP1L1 fusion and achieved hematologic and molecular remission after imatinib therapy. IGH rearrangement was observed to be a frequent molecular feature of pHES and may precede B-cell clonal expansion and evolution into B-cell malignancies in children.

Idiopathic thrombocytopenic purpura (ITP) in children.

Idiopathic thrombocytopenic purpura in children remits spontaneously in the majority of cases but most children require treatment. Between 1995 and 2005, 265 children (0-15 years old) have been consecutively observed and treated: 28 children with high doses of methylprednisolone (HDMP) (15 mg/kgx4 days), 63 with HDMP (7.5 mg/kgx4 days), 37 with HD dexamethasone (DXM) pulses, 29 with low doses of MP, and 51 with different doses of intravenous immunoglobulins (IVIG) (0.4 or 0.8 g/kg). Fifty-seven children have not been treated because of a platelet count>or=10x10(9)/L and no significant bleeding. Two hundred forty-four (92.1%) children reached a persistent CR, 237 (89.4%) after a first-line treatment or the wait and see strategy. No statistically significant differences in CR related to different treatments have been observed. IVIG and HDMP (7.5 mg/kg for 4 days) are the best treatments to reach quickly safe platelet levels>or=30x10(9)/L (3-6 days) and CR (7-11 days). Among non-responding (NR) patients, seven have been splenectomized and three reached stable CR. These results emphasize differences with adult ITP.