Hypereosinophilia in a monosomy 7 myeloproliferative disorder in childhood

Eosinophilia: secondary, clonal and idiopathic

Blood eosinophilia signifies either a cytokine-mediated reactive phenomenon (secondary) or an integral phenotype of an underlying haematological neoplasm (primary). Secondary eosinophilia is usually associated with parasitosis in Third World countries and allergic conditions in the West. Primary eosinophilia is operationally classified as being clonal or idiopathic, depending on the respective presence or absence of a molecular, cytogenetic or histological evidence for a myeloid malignancy. The current communication features a comprehensive clinical summary of both secondary and primary eosinophilic disorders with emphasis on recent developments in molecular pathogenesis and treatment.

Molecular classification and pathogenesis of eosinophilic disorders: 2005 update

Use of the term "idiopathic hypereosinophilic syndrome (HES)" has highlighted our basic lack of understanding of the molecular pathophysiology of eosinophilic disorders. However, over the last 10 years, the study of hypereosinophilia has enjoyed a revival. This interest has been rekindled by two factors: (1) the development of increasingly sophisticated molecular biology techniques that have unmasked recurrent genetic abnormalities linked to eosinophilia, and (2) the successful application of targeted therapy with agents such as imatinib to treat eosinophilic diseases. To date, most of these recurrent molecular abnormalities have resulted in constitutively activated fusion tyrosine kinases whose phenotypic consequence is an eosinophilia-associated myeloid disorder. Most notable among these are rearrangements of platelet-derived growth factor receptors alpha and beta (PDGFRalpha, PDGFRbeta), which define a small subset of patients with eosinophilic chronic myeloproliferative disorders (MPDs) and/or overlap myelodysplastic syndrome/MPD syndromes, including chronic myelomonocytic leukemia. Discovery of the cryptic FIP1L1-PDGFRA gene fusion in cytogenetically normal patients with systemic mast cell disease with eosinophilia or idiopathic HES has redefined these diseases as clonal eosinophilias. A growing list of fibroblast growth factor receptor 1 fusion partners has similarly emerged in the 8p11 myeloproliferative syndromes, which are often characterized by elevated eosinophil counts. Herein the focus is on the molecular gains made in these MPD-type eosinophilias, and the classification and clinicopathological issues related to hypereosinophilic syndromes, including the lymphocyte variant. Success in establishing the molecular basis of a group of once seemingly heterogeneous diseases has now the laid the foundation for establishing a semi-molecular classification scheme of eosinophilic disorders.

Chronic eosinophilic leukemia and hypereosinophilic syndromes. Proposal for classification, literature review, and report of a case with a unique chromosomal abnormality

The idiopathic hypereosinophilic syndromes (HES) are rare hematologic disorders characterized by persistent eosinophilia with organ involvement that encompass a wide spectrum of clinical and hematological disease states. We propose a classification scheme to further delineate these patients, and present a case of a 45-year-old male with persistent eosinophilia, severe tissue and hematologic involvement, and trisomy 15. Although multiple cytogenetic abnormalities have been associated with hypereosinophilic syndromes, this is the first reported case where trisomy 15 is the sole chromosomal abnormality.

Myelofibrosis in a child suffering from a hypereosinophilic syndrome with trisomy 8: response to corticotherapy

The idiopathic hypereosinophilic syndrome (IHS) is extremely rare in childhood and relationships of this syndrome with myeloproliferative diseases are controversial. We reported the observation of a 7-year-old girl suffering from an IHS with myelofibrosis. A clonal cytogenetic abnormality, trisomy 8, was detected in the bone marrow cells of this child. This is the decisive proof of a myeloproliferative disorder. IHS with myelofibrosis is usually considered as unresponsive to corticotherapy. In our case, corticotherapy resulted in a rapid, complete, and lasting disappearance of myelofibrosis. Complete remission of the disease, however, was not achieved and the trisomy 8 persisted after treatment.

Evidence for the clonal nature of hypereosinophilic syndrome

Hypereosinophilic syndrome (HES) is a disease process of unknown pathogenesis. Although some cases are believed to be primary hematologic malignancies, this issue remains unsolved. We present a case of HES in whom we have observed a clone of cytogenetically abnormal cells in the bone marrow in parallel with a clinical picture of a hematologic disorder characterized by progressive proliferation and organ infiltration by eosinophils. The cytogenetic abnormality 46,XY,t(7;12)(q11;p11) is previously unreported. Our case, plus other evidence present in the literature, supports the concept that HES is a hematologic malignant neoplasia.

Simple monosomy 7 and myelodysplastic syndrome in thirteen patients without previous cytostatic treatment

Thirteen patients with simple monosomy 7 presented with pallor in 11, easy bruisability in five, splenomegaly in four, no infections, refractory anaemia in all, granulocytopenia in seven, monocytosis in three, leucocytosis in four and thrombocytopenia in eight. Peripheral blood and bone marrow findings were consistent with myelodysplastic syndrome (MDS) type I in three, type II in two, type III in two, type IV in three and acute myelofibrosis in three patients. Transformations to acute leukaemia in seven patients were M2 in one, M4 in four, megakaryoblastic in one and undifferentiated in one. Lack of chromosome 7 in 12-85% of analysed cells at initial presentation of MDS progressed to nearly 100% during blastic transformation. At that time an additional change in the long arm of chromosome 3 was seen in two patients and trisomy 8 in 6% of analysed cells in a third case. The median survival time was 12 months for MDS and 3 months for acute leukaemia. Simple monosomy 7 appears to be largely confined to young children and elderly people.

Persistent Epstein-Barr virus infection associated with monosomy 7 or chromosome 3 abnormality in childhood myeloproliferative disorders

This report deals with myeloproliferative disorders associated with chronic, persistent Epstein-Barr virus (EBV) infection and with monosomy 7 and aberrations concerning chromosomes 3 and 5. Altogether five children were affected, their age ranging from 1 to 4 years at time of clinical diagnosis. Principal symptoms were: hepatomegaly, splenomegaly, recurring upper respiratory tract infection and anaemia. The serum IgG level remained persistently increased. Anti EBV antibody concentrations were measured over a period of 9 months to 6 years, demonstrating persistently increased concentrations of IgG antibodies to viral capsid antigen (VCA) and against early antigen (EA). In three patients IgA antibodies were also studied and were found to be elevated. Within 2-5 years two children developed chronic myelomonocytic leukaemia from the chronic myeloproliferative syndrome. A third patient who initially was diagnosed as chronic myelomonocytic leukaemia developed acute leukaemia within a period of 12 months. A fourth patient with myeloproliferative syndrome went into spontaneous remission after an observation period of 2 years. A fifth patient, the only one with translocation t(3;5)(q27;q33), displayed symptoms and a clinical course that can best be characterized as juvenile chronic myelocytic leukaemia. The clinical, haematological, serological and cytogenetic findings may be related.

Acute promyelocytic transformation in a case of acute myelomonocytic leukemia

An unusual case of acute myelomonocytic leukemia, with marked bone marrow eosinophilia and basophilia, is described in which there was cytogenetic evidence at presentation of acute promyelocytic transformation, with acquisition of the standard 15;17 translocation.

Bone marrow monosomy 7: hematologic and clinical manifestations in childhood and adolescence

The hematologic manifestations and clinical course are described for six children and adolescents with bone marrow monosomy 7. One child with secondary acute myelogenous leukemia had monosomy 7 plus a marker chromosome; the remaining patients had marrow monosomy 7 as the only karyotypic abnormality. The hematologic abnormalities were diverse, but the majority of patients had a smoldering preleukemic or myeloproliferative phase. Leukemic blasts were either undifferentiated or demonstrated evidence of myeloid differentiation. All patients responded poorly to antileukemic therapy. Bone marrow monosomy 7 was observed in one patient with severe marrow hypoplasia. Antileukemic therapy in another patient with greater than 30 per cent marrow blasts was associated with the development of a bone marrow myeloproliferative disorder with persistence of the monosomy 7 karyotype. We speculate that monosomy 7 may be a specific marker for a pluripotent hematopoietic stem cell abnormality that is associated with either blastic leukemia or a myeloproliferative disorder.

Pathogenetic significance of "pure" monosomy 7 in myeloproliferative disorders. Analysis of 14 cases

Monosomy 7 is frequent in acute myeloid leukaemia (AML) and in preleukaemic dysmyelopoietic syndromes but often it is not the only chromosome anomaly associated with these conditions. We report 14 patients with "pure" monosomy 7 and their clinical and haematological data are analysed in order to clarify the possible implications of this chromosome anomaly. The following points are considered: 1) In spite of the apparent variability of clinical forms in which monosomy 7 is found, several characteristics are common to all monosomy 7 patients, i.e. the presence of a preleukaemic phase and blood and marrow features suggesting the early involvement in the disease of all marrow cell lines. The different diagnoses associated with monosomy 7 are correlated with different steps of a unique myeloproliferative disease whose typical course can be reconstructed. 2) Monosomy 7 has a negative prognostic value. When it is found in a preleukaemic disorder it indicates a high risk of progression to AML, while in AML it implies recurrent infections, poor response to therapy and short survival. 3) The significance of the lack of Colton blood group antigens in monosomy 7 patients is discussed, with particular regard to the fact that the patients in whom this lack was found are the only ones who had not received transfusions in the months before the tests were done. 4) The finding of defective neutrophil chemotaxis in monosomy 7 patients is confirmed and the clinical importance of this fact is emphasized. 5) The data on the 14 patients support the opinion that AML, in general, is heterogeneous in origin. It is postulated that monosomy 7 is a marker of a specific pathogenetic pathway of AML, which implies the beginning of the malignancy in a pluripotent stem cell.