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A patient with myelofibrosis with myeloid metaplasia displaying the V617F mutation of the JAK2 gene was given an allogeneic stem cell transplantation using a reduced-intensity conditioning regimen. The patient engrafted, and as he became a chimera, the expression of the V617F mutation of the JAK2 gene decreased progressively until its disappearance. Accordingly, the concept of "molecular remission" of the myelofibrosis with myeloid metaplasia could be entertained and added to the categories of response to treatment which have been recently described., ((c) 2006 Wiley-Liss, Inc.) more...

The clinical criteria for the diagnosis of essential thrombocythemia (ET) according to the polycythemia vera study group (PVSG) do not distinguish between ET and thrombocythemia associated with early stage PV and prefibrotic chronic idiopathic myelofibrosis (CIMF). The clinical criteria of the PVSG for the diagnosis of polycythemia vera (PV) only detects advanced stage of PV with increased red cell mass. The bone marrow criteria of the World Health Organization (WHO) are defined by pathologists to explicitly define the pathological criteria for the diagnostic differentiation of ET, PV, and prefibrotic and fibrotic CIMF. As the clinical PVSG and the pathological WHO criteria show significant shortcomings, an updated set of European Clinical and Pathological (ECP) criteria combined with currently available biological and molecular markers are proposed to much better distinct true ET from early PV mimicking ET, to distinguish ET from thrombocythemia associated with prefibrotic CIMF, and to define the various clinical and pathological stages of PV and CIMF that has important therapeutic and prognostic implications. Comparing the finding of clustered giant abnormal megakaryocytes in a representative bone marrow as a diagnostic clue to MPD, the sensitivity for the diagnosis of MPD associated with splanchnic vein thrombosis was 63% for increased red cell mass, 52% for low serum EPO level, 72% for EEC, and 74% for splenomegaly indicating the superiority of bone marrow histopathology to detect masked early and overt MPD in this setting. The majority of PV and about half of the ET patients have spontaneous EEC, low serum EPO levels and PRV-1 over-expression and are JAK2 V617F positive. The positive predictive value for the diagnosis of PV of spontaneous growth of endogenous erythroid colonies (EEC) of peripheral blood (PB) and bone marrow (BM) cells is about 80-85% when either PB or BM EEC assays, and up to 94% when BM and PB EEC assays were performed. The diagnostic impact of low serum EPO levels (ELISA assay) in a large study of 186 patients below the normal range (<3.3 IU/l) had a sensitivity specificity and positive predictive value of 87%, 97% and 97.8%, respectively, for the diagnosis of PV. There is a significant overlap of serum EPO levels in PV versus control and controls versus SE. The specificity of a JAK2 V617F PCR test for the diagnosis of MPD is high (near 100%), but only half of ET and MF (50%) and the majority of PV (up to 97%) are JAK2 V617F positive. The use of biological markers including JAK2 V617 PCR test, serum EPO, PRV-1, EEC, leukocyte alkaline phosphatase score and peripheral blood parameters combined with bone marrow histopathology has a high sensitivity and specificity (almost 100%) to diagnose the early and overt stages of ET, PV and CIMF in JAK2 V617F positive and negative MPDs. more...

Polycythemia vera (PV) is a chronic myeloproliferative disorder whose major morbidity and mortality are thrombohaemorragic events and progression to acute leukaemia or myelofibrosis. Whether the haematocrit and platelet count predict such complications remains unclear. The European Collaboration on Low-dose Aspirin in Polycythemia Vera prospective study included 1638 PV patients. A total of 164 deaths (10%), 145 (8.85%) major thrombosis and 226 (13.8%) total thrombosis were encountered during 4393 person-years follow-up (median 2.8 years). In time-dependent multivariable analysis, a haematocrit in the evaluable range of 40-55% was neither associated with the occurrence of thrombotic events, mortality nor with haematological progression in the studied population. The haematocrit of patients in the highest and lowest deciles at baseline was maintained within a narrow interval of haematocrit values ranging from 40% to 47% throughout follow-up. High platelet count was associated with a lower progression rate to acute leukaemia/myelofibrosis, whereas it had no significant relationship with thrombotic events or mortality. Our findings do not suggest that the range of haematocrit (<55%) and platelet counts (<600 x 10(9)/l) we encountered in our population had an impact on the outcome of PV patients treated by current therapeutic strategies. more...

Diagnosis of the myeloproliferative disorders, polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF) is difficult due to lack of diagnostic markers. Recently, the acquisition of a mutation in the Janus kinase 2 (JAK2) gene by hemopoietic cells has been described as a genetic defect underlying myeloproliferative disorders. The mutation leads to constitutive activation of JAK2, a tyrosine kinase involved in cytokine receptor signalling. Because of the clinical importance of this mutation (JAK2 V617F) in diagnosing myeloproliferative disorders and its relevance for disease progression, we developed a semi-quantitative real-time PCR test to detect JAK2 V617F. With this assay, quantities down to 0.8% JAK2 V617F amongst wild-type DNA could reliably be detected. For quantification purposes, low intra- and inter-assay variabilities ensure good reproducibility of the assay. Thus the JAK2 V617F qPCR assay described here is quick, robust, simple and more sensitive than direct sequencing, RFLP, ARMS assay and other methods published so far to detect JAK2 V617F. We therefore believe that the assay will contribute to early diagnosis of myeloproliferative disorders and to disease management, especially when JAK2-specific inhibitors have become available for therapeutic use. more...

We present results of 2 similarly designed but separate phase 2 studies involving single-agent lenalidomide (CC-5013, Revlimid) in a total of 68 patients with symptomatic myelofibrosis with myeloid metaplasia (MMM). Protocol treatment consisted of oral lenalidomide at 10 mg/d (5 mg/d if baseline platelet count < 100 x 10(9)/L) for 3 to 4 months with a plan to continue treatment for either 3 or 24 additional months, in case of response. Overall response rates were 22% for anemia, 33% for splenomegaly, and 50% for thrombocytopenia. Response in anemia was deemed impressive in 8 patients whose hemoglobin level normalized from a baseline of either transfusion dependency or hemoglobin level lower than 100 g/L. Additional treatment effects in these patients included resolution of leukoerythroblastosis (4 patients), a decrease in medullary fibrosis and angiogenesis (2 patients), and del(5)(q13q33) cytogenetic remission accompanied by a reduction in JAK2(V617F) mutation burden (1 patient). Grade 3 or 4 adverse events included neutropenia (31%) and thrombocytopenia (19%). We conclude that lenalidomide engenders an intriguing treatment activity in a subset of patients with MMM that includes an unprecedented effect on peripheral blood and bone marrow abnormalities. more...

We conducted the first nationwide survey to clarify the clinical features, treatment methods, and prognoses for polycythemia vera (PV) and essential thrombocythemia (ET). A 1-page questionnaire was mailed to members of the Japanese Elderly Leukemia and Lymphoma Study Group (JELLSG). Surveys on 647 patients (PV, 266 patients; ET, 381 patients) were returned and analyzed. Thrombotic events at diagnosis and during follow-up occurred at rates of 15.4% and 8.5%, respectively, in PV cases and 17.6% and 8.7% in ET cases. Splenomegaly was observed in only 28.8% of PV patients and 10.8% of ET patients. The leukocyte alkaline phosphatase score was elevated in only 46.2% of PV patients. The incidences of abnormal karyotypes were less than 10% in both PV and ET cases. The rates of transformation to myelofibrosis were 2.6% in both PV and ET cases, and acute leukemia was noted in 1.1% of PV patients and 2.9% of ET patients. Prognostic factors were thrombotic history for PV and thrombotic history and age (>or=60 years) for ET. The present study clearly demonstrated clinical differences between Japanese and Western patients for PV and ET. Concerning the treatment of PV and ET, the study revealed considerable variation among Japanese hematologists. These results suggest the necessity of developing treatment guidelines according to risk stratification that are suitable for Japanese PV and ET patients. more...

Idiopathic myelofibrosis (IMF) typically presents with marrow fibrosis, splenomegaly, progressive anemia, and a leukoerythroblastic blood smear with dacryocytes. We present a patient with IMF who did not have dacryocytes. more...

We studied 25 patients with myelofibrosis with myeloid metaplasia and 19 patients with secondary myelofibrosis associated with pulmonary hypertension (PH). In these 2 groups, we compared the peripheral-blood CD34 count, the clonality of granulocytes and platelets in peripheral blood, the mutational status of the JAK2 kinase gene, and the morphology of the peripheral blood and bone marrow. We found that the following were distinctive features of myelofibrosis with myeloid metaplasia but not of secondary myelofibrosis due to PH: high circulating CD34 cell count, the presence of clonal platelets and granulocytes and of peripheral-blood dacrocytes, and a JAK2 1849G>T (V617F) mutation. We conclude that these are intrinsic features of clonal progenitors present in patients with myelofibrosis due to myeloproliferative disorders and that these features are not due to the abnormal marrow architecture seen in secondary myelofibrosis. more...

The aim of the study was the evaluation of the participation of fibrinolytic system in the pathogenesis of haemostasis disturbances on the base of the determination of plasminogenesis intensity and some other fibrinolytic parameters. The study was performed in the group of 73 patients suffering from chronic meyloproliferative syndromes aged 36-78 (means 54,0) years: in 22 with chronic myelogenous leukemia (CML), in 25 with polycythemia vera (PV), in 21 with essential thrombocythemia (ET) and in 5 patients with meylofibrosis (MF). Control group contained 30 healthy volunteers sex and age matched. In the citric plasma obtained from venous blood concentration of plasmin-alpha2 antiplasmin complexes (PAP) using immunosorbed method (ELISA), alpha-2-antiplasmin with chromogenic method, concentration of fibrinogen and fibrin/ /fibrinogen degradation products (FDP) were determined. In blood plasma of patients with chronic myeloproliferative syndromes increased concentration of PAP complexes was detected what is the evidence of high intensity of plasmin generation. more...

Myelofibrosis is an uncommon phenomenon associated with a variety of neoplastic and inflammatory processes. Although there is evidence that cytokines elaborated by clonal malignant hematopoietic cells are implicated in myelofibrosis in primary hematologic disorders, there has been little data to date on the pathophysiology of myelofibrosis in autoimmune disorders. Here we report a case of autoimmune myelofibrosis with pancytopenia. Peripheral blood monocytes and CD4-positive lymphocytes produced significantly elevated levels of transforming growth factor beta (TGF-beta) compared to similar cells from healthy volunteer controls. TGF-beta has been implicated in the pathogenesis of myelofibrosis associated with primary hematological malignancies. Furthermore, substance P, previously linked to myelofibrosis, was also detected in elevated levels in the patient's serum and correlated negatively with the levels of the patient's blood counts. These findings suggest a role for both TGF-beta and substance P in the pathophysiology of autoimmune myelofibrosis. This is the first report of deregulated production of TGF-beta by monocytes in the pathobiology of autoimmune myelofibrosis. more...

Idiopathic myelofibrosis (IMF) is characterized by anemia, progressive splenomegaly, bone marrow fibrosis, and extramedullary hematopoiesis. However, patients with a transitional myeloproliferative disorder (MPD), a prefibrotic form of myelofibrosis, or myelofibrosis with a fatty bone marrow share many features of IMF but have clinical characteristics that deviate from the classical description of IMF. A phenomenon that serves as a unique biomarker of IMF is the constitutive mobilization of hematopoietic progenitor cells (HPCs) and/or endothelial progenitor cells (EPCs) from the bone marrow to the peripheral blood and other extramedullary sites. Using such parameters as hemoglobin level, white blood cell count, and number of blasts in the peripheral blood, prognostic scores can be developed by which to base therapeutic decisions. Androgens, recombinant human erythropoietin (rHuEpo), and thalidomide are effective modalities of treatment of the anemia of IMF. Systemic symptoms of excess myeloproliferation are the primary indication for treatment with chemotherapeutic agents. Hydroxyurea is the most commonly used drug. Ablation of the abnormal hematopoietic clone with high-dose chemotherapy and allogeneic stem cell transplantation offers an opportunity to cure patients with IMF. The use of fully myeloablative conditioning regimens, with or without total body irradiation, is associated with a high transplant-related mortality rate (27% to 48%), especially in patients with advanced disease and in the elderly. The use of reduced intensity conditioning (RIC) regimens has resulted in prolonged survival and lower transplant-related mortality. more...

Purpose: Endothelial progenitor cells (EPCs) are present in circulation and contribute to vasculogenesis in adults. We measured the number of circulating EPCs in patients with myelofibrosis with myeloid metaplasia (MMM), and we examined the relationship between the number of EPCs and severity of the MMM disease process., Patients and Methods: The number of EPCs was measured by assaying the CD34+CD133+ vascular endothelial growth factor receptor 2 (VEGFR2) -positive cell phenotype in 110 MMM patients, 16 patients with other Philadelphia-negative chronic myeloproliferative disorders (Ph-negative CMPDs), and 14 healthy participants. In four MMM patients, the capacity of selected CD34+ cells to form endothelial colonies (CFU-End) in vitro was tested., Results: CD34+, CD133+, and VEGFR2-positive EPCs were detectable in unselected peripheral-blood cells of 50.9% MMM patients, 37.5% control patients, and 21% healthy participants. Patients with MMM had a median of 0.26% EPCs, significantly higher than that in healthy controls (median, 0%) and in patients with other Ph-negative CMPDs (median, 0.1%). In 14.5% of MMM patients, the numbers of EPCs were greater than the highest value found in patients with other Ph-negative CMPDs. CD34+ selected cells produced colony-forming unit-endothelial (CFU-End), which were vascular endothelial (VE) -cadherin positive, CD31+, von Willebrand factor positive, and CD45-. In MMM patients, the larger the number of EPCs, the smaller the number of circulating immature myeloid cells and circulating CD45+CD34+ hematopoietic progenitor cells. Increased numbers of EPCs were associated with younger age and a diagnosis of prefibrotic MMM., Conclusion: Circulating EPCs are elevated in MMM patients in the early stage of the disease. Heightened mobilization of EPCs may represent an important mechanism for development of neoangiogenesis in MMM. more...

Idiopathic myelofibrosis (IM) is characterized by increased numbers of CD34(+) cells in the peripheral blood (PB). We explored the possible mechanisms underlying this abnormal trafficking of CD34(+) cells. Plasma levels of neutrophil elastase (NE), total and active matrix metalloproteinase 9 (MMP-9), and soluble vascular cell adhesion molecule-1 (sVCAM-1) were dramatically increased in IM. The absolute number of CD34(+) cells in the PB was correlated with the levels of sVCAM-1. Marked elevations of the levels of NE but not total and active MMP-9 as well as MMP-2 were detected in media conditioned by IM mononuclear cells (MNCs) as compared with that of healthy volunteers. IM MNC-conditioned media, however, was shown by zymographic analysis to contain increased gelatinolytic activity corresponding to the molecular weight of MMP-9. IM MNC-conditioned media also exhibited a greater ability to cleave VCAM-1 and c-kit in vitro, consistent with the biologic actions of NE. In addition, the increased ability of IM PB CD34(+) cells to migrate through a reconstituted basement membrane was diminished by several inhibitors of MMP-9 activity, indicating that these cells express increased levels of this MMP. These data indicate that a proteolytic environment exists in IM which might result in the sustained mobilization of CD34(+) cells. more...

The release of transforming growth factor-beta1 (TGF-beta1) in the bone marrow microenvironment is one of the main mechanisms leading to myelofibrosis in murine models and probably in the human idiopathic myelofibrosis (IMF). The regulation of TGF-beta1 synthesis is poorly known but seems regulated by nuclear factor kappaB (NF-kappaB). We previously described the overexpression of an immunophilin, FK506 binding protein 51 (FKBP51), in IMF megakaryocytes. Gel shift and gene assays show that FKBP51's overexpression in a factor-dependent hematopoietic cell line, induces a sustained NF-kappaB activation after cytokine deprivation. This activation correlates with a low level of IkappaBalpha. A spontaneous activation of NF-kappaB was also detected in proliferating megakaryocytes and in circulating CD34(+) patient cells. In normal cells, NF-kappaB activation was only detected after cytokine treatment. The expression of an NF-kappaB superrepressor in FKBP51 overexpressing cells and in derived megakaryocytes from CD34(+) of IMF patients revealed that NF-kappaB activation was not involved in the resistance to apoptosis after cytokine deprivation of these cells but in TGF-beta1 secretion. These results highlight the importance of NF-kappaB's activation in the fibrosis development of this disease. They also suggest that FKBP51's overexpression in IMF cells could play an important role in the pathogenesis of this myeloproliferative disorder. more...

Myelofibrosis is usually observed in myeloproliferative disorders, such as chronic myeloid leukemia. However, there are only a few reports showing an association between T-cell lymphoma and myelofibrosis. We report a case of peripheral T-cell lymphoma, unspecified (diffuse large cell) type, involving the bone marrow that was associated with severe myelofibrosis. In the present case, the plasma concentration of transforming growth factor-beta1 (TGF-beta1) was increased to 8.95 ng/ml (normal range: 1.56-3.24 ng/ml). No lymphadenopathy or skin lesions were observed during the entire clinical course. Although the mechanism of secondary myelofibrosis is still unclear, elevated plasma TGF-beta1 might be involved in the pathogenesis of bone marrow fibrosis in the present case. more...

Idiopathic myelofibrosis (IM) is characterized by the constitutive mobilization of CD34(+) cells. IM peripheral blood (PB) CD34(+) cells had a reduced cloning efficiency and a lower frequency of cobblestone areas compared with normal granulocyte colony-stimulating factor (G-CSF)-mobilized PB CD34(+) cells. IM CD34(+) cells engrafted nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice, demonstrating that they contain bone marrow (BM)-repopulating cells. G-CSF-mobilized CD34(+) cells produced multiple hematopoietic lineages within the NOD/SCID mice with a predominance of CD19(+) cells. By contrast, IM CD34(+) cells produced predominantly CD33(+) cells, increased numbers of CD41(+) cells, but fewer CD19(+) cells. Transcriptional clonality assays of the engrafted human IM cells demonstrated their clonal origin. CD34(+) cells from one patient isolated prior to leukemic transformation were capable of generating acute leukemia in NOD/SCID mice. The engrafted human cells exhibited the same abnormal karyotype as primary cells in a portion of the population. These findings demonstrate that BM-repopulating cells and more differentiated progenitor cells are constitutively mobilized into the PB in IM, and that their differentiation program is abnormal. In addition, the NOD/SCID model may be useful in gaining an understanding of the events occurring during the transition of IM to acute leukemia. more...

A case of a leukemic transformation following a 27-year history of idiopathic myelofibrosis (IMF) is presented. The patient had two chromosomal abnormalities: a deletion of chromosome 13, del 13(q12q14), and a deletion of chromosome 11, del 11(q14q23). This patient's final diagnosis was acute micromegakaryocytic leukemia, and she died 1 month after leukemic transformation with an additional chromosomal abnormality, trisomy 8. IMF with myeloid metaplasia associated with deletion of the long arms of chromosomes 11 and 13 has not been previously reported. We speculate that the leukemic transformation in this patient was associated with chromosomal abnormalities del 11 and trisomy 8. more...

Objective: The aim of this study is to investigate the mechanism of osteosclerosis in IMF in relation to OPG derangement., Methods: Plasma OPG level was assayed by OPG ELISA in 19 patients with IMF, 15 patients with other myeloproliferative disorders (MPDs), and 12 normal volunteers as controls and correlated with the degree of osteosclerosis. Furthermore, the level of OPG mRNA, in the cultured bone marrow stromal (BMS) cells of patients with IMF and anemia patients used as controls, in the presence or absence of TGF-beta1, was studied by real-time RT-PCR., Results: The present study showed that blood OPG level was significantly elevated in patients with IMF as compared to patients with other MPDs (p < 0.01) or normal volunteer controls (p < 0.05), and there was no significant difference in the level between patients with MPDs and controls. In addition, there was a positive correlation (r=0.67, p=0.04) between plasma OPG levels and the degree of osteosclerosis. There was no difference in the OPG mRNA in patients with IMF as compared with controls even on TGF-beta1 stimulation., Conclusion: These results suggest that osteosclerosis in IMF may be related to overproduction of OPG and enhanced level of OPG is not due to the effect of TGF-beta1 on the BMS cells. It could be due to the effect of TGF-beta1 or other growth factors on cells other than BMS cells such as the osteoblasts. more...

The clinical, cytogenetic, and immunophenotypic features in 12 adult patients with acute panmyelosis with myelofibrosis (APMF; ICD-0-3: 9931/3; C42.1) are reported (median age: 57 years; f/m = 1.4). The white cell count (WBC) was normal in 3 patients; 9 had leucopenia. The median hemoglobin value was 64.5 g/l, and median platelet count 12 x 10(9)/l. Bone marrow biopsy showed a hypercellular marrow in 10/12 patients with a significant infiltration of pathological blasts (range: 30 - 60%). All the cases had marked reticulin fibrosis. Immunophenotyping of bone marrow blast cells showed the expression of early (CD34) and lineage-unspecified antigens (HLA-DR) in 6/7, and 7/7 patients, respectively. "Early" myeloid antigens (CD13, CD33) were seen in 6/7 and 4/6 patients respectively. Monocyte antigen (CD14) was expressed in 3/7 patients. Megakaryocyte antigen (CD61) and erythroid cell antigen (GpA) were each expressed in only 1 patient. Two patients had expression of CD34, HLA-DR and "early" myeloid antigens by their bone marrow blast cells and 1 of these also had a co-expression of the antigens from a differentiated monocytic cell proliferation (lysozyme+, CD68+). Nonspecific chromosomal aberrations were recorded in 8/10 patients. The median survival was 2 months. These findings suggest an immature myeloid phenotype of blast cells in APMF. In 6/9 patients a leukemic cell differentiation into monocytic, megakaryocytic or erythroid lineage was also demonstrated., (Copyright 2004 Taylor and Francis Ltd) more...

Basic fibroblast growth factor (bFGF) is an important growth factor involved in clonal hematopoietic expansion, neoangiogenesis, and bone marrow fibrosis, all of which are important pathobiologic features of clonal chronic myeloproliferative disorders (CMPD) and myelodysplastic syndromes (MDS). The aim of this study was to assess circulating bFGF concentrations in patients with CMPD and MDS with respect to the presence of bone marrow fibrosis in histopathologic examination. The study group comprised 18 patients with CMPD (six female, 12 male; median age 50 years), seven patients with MDS (one female, six male; median age 66 years) and 10 healthy adults as controls (four female, six male; median age 29 years). CMPD group included six chronic myelogenous leukemia (CML), seven essential thrombocythemia (ET), three polycythemia vera (PV), two agnogenic myeloid metaplasia (AMM). All seven MDS patients were the FAB subtype of refractory anemia (RA). Bone marrow biopsy sections stained with hematoxylin and eosin (H & E) and for reticulin were examined for the presence of fibrosis. The median plasma bFGF level was 18.2 pg/ml (interquartile range, IQR: 15.2-26.7) in patients with CMPD, 18.0 pg/ml (IQR: 15.8-26.4) in patients with MDS, 13.6 pg/ml (IQR: 9.9-20.0) in the control group. The bFGF levels were significantly higher in patients with CMPD in comparison with the healthy control group (P = 0.031). Circulating bFGF tended to be significantly lower in relation to the development of marrow fibrosis (P = 0.028). The complicated interactions of bFGF and fibrosis in the context of CMPD may be either 'cause' or 'effect'. The bFGF might represent an important link between angiogenesis, fibrosis, and clonal neoplastic hematopoiesis during the development of CMPD. more...

A series of 24 consecutive patients affected by myelofibrosis with myeloid metaplasia was reviewed. The clinical-pathological features at onset were similar to those reported in literature; in particular in all the patients we observed splenomegaly and the typical leuko-erythroblastic picture in peripheral blood. The median survival of our series was of 57 months; the deaths were caused by severe anaemia and/or infection and/or haemorrhage; the blastic terminal transformations were rare. According to other authors, unfavourable prognostic factors in our patients were: male sex, advanced age, hepatomegaly, the presence of systemic signs, anaemia, leukocytosis, leukopenia, high number of circulating erythroblasts, thrombocytopenia, osteomyelosclerosis. We have confirmed the clinical value of three staging prognostic systems: the system proposed by Njoku based on haemoglobin level and reticulocytes number, the system proposed by Visani based on haemoglobin and circulating myeloid precursors number, the system proposed by Dupriez based on haemoglobin and white blood cells number. more...

Four years have passed since publication of the latest update in clinical criteria for the diagnosis of polycythemia vera. During this time, the first molecular markers for polycythemia vera have been described. They include decreased expression of the thrombopoietin receptor, c-Mpl, and overexpression of the polycythemia rubra vera-1 messenger RNA. These biomarkers, which are not in themselves the causative changes leading to disease development but nonetheless appear intricately linked to the pathological process, may constitute a useful addition to our diagnostic repertoire. This review examines both the currently available clinical criteria and the possible role of biomarkers in the diagnosis of polycythemia vera. From this discussion, a refined set of diagnostic criteria for polycythemia vera is proposed., (Copyright Future Drugs Ltd.) more...

Idiopathic myelofibrosis (IMF) is a clonal stem cell disorder and is one of the four major myeloproliferative disorders, which include essential thrombocythemia (ET), polycythemia vera (PV), and chronic myelogenous leukemia (CML). Patients may be asymptomatic at the early stages, but later progress to marrow fibrosis, splenomegaly with pancytopenia leading to anemia, and other constitutional symptoms. Most of the care available is supportive and only palliates the constitutional symptoms. Prognosis for these patients is dependent on karyotype, hemoglobin count, and age. Stem cell transplantation is the only curative therapy, which results in eradication of the stem cell clone, with the cessation of extramedullary hematopoiesis and resolution of marrow fibrosis and its sequelae. Stem cell replacement therapy using either autologous or allogeneic stem cells has been attempted in small populations of patients with variable benefit. A nonmyeloablative approach has shown promise in a very small number of patients, but additional investigation is required for the ideal management of these patients. more...

Neoangiogenesis is an integral component of bone marrow myeloproliferation in patients with myelofibrosis with myeloid metaplasia (MMM). As extramedullary haematopoiesis is a constitutive feature of MMM, we studied spleen neoangiogenesis by a computerized image analysis in MMM patients. Compared with five normal subjects, spleen CD34-staining capillary vascular density (CVD) was 2.1-3.03 times higher than the upper range of normal in six of the 15 (40%) MMM patients. CD8-staining sinusoidal vascular density (SVD) was constantly normal or lesser than normal and was inversely correlated with CVD (R = -0.53; P = 0.04). In MMM patients who did not receive cytoreductive or radiation therapy in the month before splenectomy (n = 9), the CVD was a significant determinant of spleen size (R = 0.88; P = 0.04). In MMM patients, the number of spleen CD34+ haematopoietic stem cells was increased from 1.2 to 98 times the upper limit of normal, and predicted the expansion of CVD (R = 0.57; P = 0.03). A population of cells expressing the CD34+/CD133+/VEGFR-2+ angiopoietic phenotype was present in the blood and spleen of five of seven patients. These results document that neoangiogenesis is an integral component of spleen re-localization of haematopoietic stem cells and suggest a cellular mechanism for spleen neoangiogenesis. more...

Malignant megakaryopoiesis can cause chronic or acute myelofibrosis through production of fibrogenic cytokines. Chronic myelofibrosis is a clonal disorder with marrow fibrosis, myeloid metaplasia, gross splenomegaly, and teardrop cells. Acute myelofibrosis differs by its aggressiveness, by the fact that it is more common in children, and by lack of organomegaly or anisopoikilocytosis. Surprisingly, in early childhood and infancy, splenomegaly and teardrop red cells become an important feature. Infantile myelofibrosis is a rare disease, except in Down syndrome. Familial occurrence of infantile myelofibrosis is exceedingly rare. The author describes an unfortunate family whose four consecutive children died of a very fulminant form of acute myelofibrosis during their first year of life. The fulminant nature of the disease, the degree of splenomegaly, and the prominence of anisopoikilocytosis were even more marked than in currently reported cases of infantile myelofibrosis. The mode of inheritance remained illusive. With two female children, sex-linked inheritance was not possible. It could not have been inherited in an autosomal dominant fashion with normal parents and with two normal children from the father's second marriage. A new autosomal dominant mutation in the germ cell of either parent is another possibility. Autosomal recessive inheritance remained a logical explanation, although such a high degree of disease presentation in a non-consanguineous marriage seems to put that possibility in question. more...

Background and Objectives: The levels of circulating hematopoietic progenitor cells are often increased in myelofibrosis with myeloid metaplasia (MMM). The prognostic relevance of this phenomenon is largely unknown., Design and Methods: We determined the number of circulating myeloid (CFU-GM), erythroid (BFU-E), and pluripotent (CFU-GEMM) progenitors, in 110 patients with MMM at diagnosis using a semi-solid colony assay. Overall survival was investigated by plots of the Kaplan-Meier estimator; known risk factors and the number of circulating progenitor cells were tested by univariate and multiple Cox regression analysis., Results: Univariate analysis showed that hemoglobin concentration (p=0.019), CFU-GM (p< 0.0001), BFU-E (p=0.002), and age (p=0.002) predicted survival. Numbers of circulating CFU-GM above the 75th percentile were associated with a significantly shorter survival than were CFU-GM levels at or below the 75th percentile (27 vs. 74 months, p=0.0007). Similarly, high numbers of BFU-E in peripheral blood (> 75th percentile) predicted a shorter survival (33 vs. 74 months; p=0.007). When myeloid and erythroid progenitor cells were calculated separately in the multiple Cox regression analysis, both CFU-GM (hazard ratio 2.8, 95% CI, 1.35 to 5.93) and BFU-E (hazard ratio 2.57, 95% CI, 1.26 to 5.21) numbers above the 75th percentile were independent adverse prognostic factors in our patients., Interpretation and Conclusions: High levels of circulating myeloid and erythroid progenitor cells are novel risks factors in patients with MMM. The assessment of hematopoietic progenitor cells may be useful to determine risk-adjusted treatment strategies. more...

Extracellular proteolytic enzymes of the urokinase-type plasminogen activator (uPA) system and the family of metalloproteinases (MMPs) catalyse the matrix degradation and remodelling processes characteristic of invasive malignant disorders. In a cohort of 50 patients with chronic myeloproliferative disorders (MPD) serum markers for collagen metabolism were compared to plasma levels of enzymes of the uPA and MMP system. Serum aminoterminal propeptide of type III procollagen (S-PIIINP) (P < 0.0001) concentration was significantly higher in the patients (median 3.7 micro g/L vs. 2.5 micro g/L) compared with controls. In a subgroup analysis comprising patients with myelofibrosis (MF), polycythaemia vera (PV) and essential thrombocythaemia (ET), respectively, S-PIIINP levels differed significantly with the highest values found in patients with MF (MF vs. PV vs. ET; P = 0.0027). Serum concentration of carboxyterminal telopeptide of type I collagen (S-ICTP) (P = 0.0006), reflecting type I collagen degradation, was significantly higher in patients compared with controls (median 4.0 micro g/L vs. 2.7 micro g/L). When comparing S-ICTP measurements between patient subgroups and controls there were only significantly higher values among MF and PV patients (MF vs. controls; P < 0.0001, PV vs. controls; P = 0.0016). A significant correlation between the marker for collagen synthesis (S-PIIINP) and degradation (S-ICTP) (r = 0.59; P < 0.0001) was demonstrated. A correlation analysis between serum markers for bone marrow remodelling processes (S-PIIINP, S-ICTP and S-hyaluronan) and plasma-soluble urokinase plasminogen receptor (suPAR) disclosed a significant relationship between suPAR and S-PIIINP (r = 0.48; P = 0.0009), S-hyaluronan (r = 0.56; P < 0.0001) and S-ICTP (r = 0.47; P = 0.0013), respectively. Plasma levels of MMP-2 and -9 were not correlated to serum markers for collagen metabolism. These findings suggest that enzymes of the uPA system might participate in the bone marrow remodelling processes characteristic of MPD. more...

In chronic idiopathic myelofibrosis (CIMF) the factors predicting survival in patients who were already in the fibrotic stage have been well documented by numerous studies. Prefibrotic stages were only rarely evaluated so that the prognostic impact of myelofibrosis is currently not well known. Also predictive factors for disease-related events were not included in those studies. Thus, we evaluated the prognostic impact of myelofibrosis and other histopathological (megakaryocytes, blasts) and clinical [age, gender, splenomegaly, chemotherapy, hemoglobin (Hb), leukocyte, and platelet count] parameters in 122 patients in fibrotic and prefibrotic stages of CIMF on event-free survival. The statistical analysis was performed using the univariate log-rank test and the multivariate recursive partition and amalgamation (RECPAM) approach. In 62 patients disease-related events occurred during a mean observation period of 58 months. In univariate analysis they were associated with blast increase in the bone marrow. In RECPAM analysis a shorter event-free survival was found in anemic patients (mean: 9.3 months). In nonanemic patients older than 60 years, advanced myelofibrosis was associated with a shorter event-free mean survival of 23.2 months versus 69.3 months in less advanced cases. A slight or moderate myelofibrosis was not found to have a prognostic impact on event-free survival. The longest event-free survival was found in nonanemic patients who were younger than 60 years (mean: 185 months), regardless of the grade of myelofibrosis. Thus, we found that the most relevant prognostic parameter for event-free survival in CIMF were the Hb value, age, and grade of myelofibrosis. more...

Background and Objectives: Flow cytometry enumeration of peripheral blood CD34-positive cells provides reliable measurements of circulating hematopoietic progenitors in humans. Since the absolute number of circulating CD34-positive cells has been previously found to be elevated in myelofibrosis with myeloid metaplasia (MMM), we prospectively studied the clinical utility of this parameter in the work-up of patients with chronic myeloproliferative disorders., Design and Methods: Of the 248 consecutive patients enrolled in this study, 106 had polycythemia vera (PV), 90 essential thrombocythemia (ET), and 52 myelofibrosis with myeloid metaplasia (MMM). The study population included both newly diagnosed and established cases, and of these latter some patients were on cytoreductive treatment while others were chemotherapy naive. Both cross-sectional and longitudinal investigations were carried out. Flow cytometry enumeration of CD34-positive cells was performed using a single-platform assay., Results: Median numbers and ranges of circulating CD34-positive cells were 2.3x10(6)/L (0-5) in 20 control subjects, 2.2x10(6)/L (0-14) in those with PV, 2.4x10(6)/L (0-14) in those with ET, and 114x10(6)/L (6-2,520) in MMM patients. Analysis of variance demonstrated that values were markedly higher in MMM patients than in the remaining groups, and counts did not appear to fluctuate over short periods of follow-up. In both cross-sectional and longitudinal investigations on patients at clinical onset and/or out of cytoreductive treatment, a CD34-positive count of > or = 15x10(6)/L was always associated with MMM, clearly indicating a disease-related specificity., Interpretation and Conclusions: The absolute number of circulating CD34-positive cells is normal or anyhow lower than 15x10(6)/L in patients with uncomplicated PV or ET, whereas it is equal or above this cut-off in those with MMM, likely reflecting abnormal hematopoietic progenitor cell trafficking. Thus, enumeration of circulating CD34-positive cells may be useful in the work-up of patients with myeloproliferative disorders. more...

R115777 is an orally bioavailable farnesyltransferase inhibitor (FTI) that has displayed encouraging activity in patients with acute myeloid leukemia. To determine whether R115777 might exert similar activity in myelofibrosis with myeloid metaplasia (MMM), we evaluated its effects on circulating myeloid progenitor cells from patients with MMM (n=25) using in vitro colony-forming assays. The median R115777 concentrations that inhibited colony formation by 50% were 34 and 2.7 nM for myeloid and megakaryocytic colonies from MMM patients, respectively. Progenitors from normal controls and patients with other myeloproliferative disorders demonstrated similar sensitivity. Since the ras polypeptides are one putative target of FTIs, the potential role of ras effectors was examined by incubating parallel progenitor assays with the phosphatidyl-inositol-3 (PI-3) kinase inhibitor LY294002 and the mitogen-activated protein kinase 1 inhibitor PD98059. MMM progenitor colonies (n=7) were highly sensitive to LY294002 but not to PD98059, implying that the PI-3 kinase pathway may be critical for survival and proliferation of these cells. In addition to indicating that MMM progenitors are sensitive to clinically achievable R115777 concentrations in vitro, these results provide a potential explanation for the thrombocytopenia observed with R115777 during the treatment of other hematologic malignancies. more...

We investigated the clinical activity of the farnesyl transferase inhibitor R115777 in 22 patients with chronic myelogenous leukemia (CML) in chronic, accelerated, or blastic phase and in 8 patients with myelofibrosis (MF) and 10 patients with multiple myeloma (MM). R115777 was administered at 600 mg orally twice daily for 4 weeks every 6 weeks. Seven patients with CML (6 in chronic phase, 1 in advanced phase) achieved complete or partial hematologic response. Four of them had a minor cytogenetic response. Responses were transient, with a median duration of 9 weeks (range, 3-23 weeks). Two patients discontinued therapy because of toxicity while in complete hematologic response. Two MF patients had a significant decrease in splenomegaly, one had normalization of white blood cell count and differential, and one became transfusion independent. One patient with MM had a reduction in monoclonal protein of 34%. Adverse events included nausea in 22 patients (55%; all grade 2 or lower) and fatigue in 19 (48%; grade 3 or higher in 1). Other grade 3 or 4 toxicities included skin rash (4 patients, 10%), peripheral neuropathy (2 patients, 5%), and liver toxicity (2 patients, 5%). Patients who responded to therapy had significantly higher plasma vascular endothelial growth factor (VEGF) concentrations prior to treatment than nonresponders. Plasma concentrations decreased significantly during therapy among responders. R115777 showed clinical activity in patients with CML and MF. The effect on VEGF needs to be further investigated to determine whether this might be a possible mechanism of action of R115777. more...

Thrombopoietin (TPO) is recognized as the primary regulator of megakaryocyte and platelet production. Two alternative hypotheses for the mechanism of regulation have been proposed: (1) platelet and/or megakaryocyte mass regulate circulating TPO levels by binding to TPO through TPO receptors (c-MPL), with subsequent internalization and degradation of the protein; (2) TPO mRNA produced by bone marrow (BM) stromal cells or BM cells modulates blood TPO levels or platelet counts. In myeloproliferative disorders (MPD), including primary myelofibrosis (MF) and essential thrombocythemia (ET), elevated blood TPO levels occur despite increased platelet and megakaryocyte mass. Therefore, in these diseases, elevated blood TPO levels cannot be explained by the first mechanism. The present study, was designed to measure TPO mRNA production by BM mononuclear cells and BM stromal cells using a relative RT-PCR technique, to verify the second mechanism. We found no increase of TPO mRNA production in either BM cells or in BM stromal cells in patients with MF and ET. Furthermore, in those patients with MF who had elevated plasma TPO levels, TPO mRNA levels in bone marrow fibroblasts (BMFs) or BM cells were not elevated as compared with controls. Therefore, we concluded that in patients with MF, the elevated plasma TPO levels are not due to enhanced production of TPO mRNA either by BMF, or BM cells. The TPO receptor (c-MPL) abnormalities including reduced MPL protein levels or defective TPO induced signal transduction pathways are the likely mechanisms. more...

Agnogenic myeloid metaplasia (AMM) is characterized by bone marrow fibrosis with abnormal accumulation of extracellular matrix components (ECM), which is dependent on the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Twenty-five patients with AMM, 30 with essential thrombocythemia (ET), 12 with polycythemia vera (PV) and 20 normal control subjects were studied. AMM patients had decreased plasma levels of MMP-3 and marked elevated levels of TIMP-1, but MMP-1, MMP-2 and MMP-9 levels were not significantly different from control subjects. Elevated levels of plasma TIMP-1, but not MMPs, were found in ET and PV. Reduced MMP activity together with increased TIMP-1 activity may be essential in fibrosis formation. more...

Introduction: Changes in platelet count and function contribute to thrombo-hemorrhagic episodes in chronic myeloproliferative syndromes (MPS). We used flow cytometry to study platelet-leukocyte conjugates and markers of platelet activation in patients with MPS., Methods: Whole blood from patients with chronic myelogenous leukemia (CML), polycythemia vera (PV), chronic myelofibrosis (MF), and essential thrombocythemia (ET) and from healthy volunteers was prepared for flow cytometry. Platelet microparticles and platelet microaggregates were identified with anti-CD42b and forward scatter, activated platelets with anti-CD62p. Anti-CD42b, anti-CD14, and anti-CD45 were used to study platelet-leukocyte conjugates., Results: The percentage of CD62p-positive platelets was elevated in all myeloproliferate syndrome subtypes. The median percentage of platelet microparticles was 5.2% in controls and significantly higher in PV (12.0%), MF (11.0%), and ET (11.0%, all p<0.05). There was an increased percentage of platelet-neutrophil conjugates in patients with PV (8.3%) and ET (10.4%) compared to normal controls (6.8%, all p<0.05). Platelet-monocyte conjugates were 8.0% in controls and elevated in PV (15.4%) and ET (15.0%, all p<0.05). Patients with a history of venous or arterial thrombotic events had slightly less platelet-leukocyte conjugates and slightly more microparticles than patients without thrombosis; however, this difference was not statistically significant., Conclusions: These findings suggest that platelet-leukocyte conjugate formation occurs in myeloproliferative syndromes and indicates platelet activation. Also, platelet microparticles are elevated and might provide a catalytic surface for thrombin generation. This could explain the clinical observation that patients with myeloproliferative syndromes have an increased risk to experience arterial or venous thrombotic events. more...

Extracellular proteolytic enzymes of the urokinase-type plasminogen activator (uPA) system and the family of metalloproteases play a crucial role in the matrix degradation and tissue remodelling processes characteristic of malignant disorders. The receptor for urokinase plasminogen activator (uPAR) serves to localise and intensify the action of uPA and is expressed on the surface of malignant as well as tumour stromal cells including fibroblasts. A soluble form of uPAR (suPAR) cleaved from its glycosyl-phosphatidylinositol anchor is detected in plasma from healthy individuals and increased levels of suPAR have been found in advanced malignancy, suggesting that suPAR may be a marker of extensive tissue remodelling. In an attempt to clarify whether suPAR might be a marker for bone marrow tissue remodelling we measured plasma suPAR levels in a patient cohort comprising 17 with myelofibrosis (MF), 17 with polycythaemia vera (PV), 15 with essential thrombocythaemia (ET), one with a transitional myeloproliferative disorder evolving from PV and 30 controls. Compared with controls suPAR levels were significantly higher in the patients (P < 0.0001) (median 3.35 vs. 2.32 microg L(-1)). Moreover, in subgroup analyses including patients with MF, PV, and ET, respectively, suPAR levels differed significantly with the highest levels found in patients with MF and PV (MF vs. PV vs. ET; P = 0.0003). When comparing suPAR levels of the individual patient subgroups with controls, only suPAR levels of PV and MF patients were significantly increased (P < 0.0001). Sixty-five percent of patients with PV and MF (22/34) had suPAR plasma values that were above the mean +2 standard deviations (SD) of controls. The concentration of suPAR was significantly correlated to plasma lactate dehydrogenase, thrombomodulin, and complex of tPA:PAI-1 in the patients. There was no difference between patients and controls when comparing plasma uPA levels. Increased plasma suPAR levels in patients with chronic myeloproliferative disorders may reflect increased uPAR production in the bone marrow, leading to enhanced bone marrow remodelling. more...

The aim of the present work was to compare the results for some haematological variables in 12 patients with idiopathic myelofibrosis (IMF) with those of 21 patients with polycythaemia vera (PV), 22 patients with essential thrombocythaemia (ET) and 10 healthy control subjects. In each patient and control subject peripheral blood was used for analysis of flow cytometric measurement of CD34-positive (CD34+) cells, in vitro colony growth and plasma erythropoietin (EPO) concentration. The mean concentration of CD34+ cells in the IMF group was 568 +/- 686 x 10(3) mL, which significantly (P<0.001 for each group) exceeded the means in PV, ET and control groups ((10.2 +/- 32.0) x 10(3) mL, 3.0 +/- 3.7 x 10(3) mL and 1.9 +/- 0.8 x 10(3) mL, respectively). The mean number of EPO-independent erythroid colonies (EEC) was 110 +/- 215 colonies per 10(5) cells for the IMF patients. In comparison with the means for PV and ET patients (40 +/- 140 and 12 +/- 27 colonies per 10(5) cells, respectively) the difference did not reach statistical significance. The mean EEC for IMF patients was, however, significantly higher compared with the mean for the control subjects (P<0.05). The means for total erythroid colony growth with EPO added to the growth medium as well as for granulocyte-macrophage colony-forming units were significantly higher in the IMF group compared with the means for PV, ET and control groups (P<0.001 for each group). The mean plasma EPO was 204 +/- 290 IU/L in the patients with IMF compared with 6.6 +/- 7.9 IU/L in PV patients, 19.1 +/- 23.2 IU/L in ET and 10.3 +/- 7.8 IU/L in the control subjects. Due to considerable differences in haemoglobin concentrations no relevant conclusions could be drawn from the results for plasma EPO concentrations. Indeed, the majority of patients with IMF, PV and ET were on myelosuppressive treatment; additionally most PV patients received phlebotomy therapy. The results of the present study suggest that the circulating pool of stem cells and progenitor cells in peripheral blood is significantly increased in IMF patients compared with PV and ET patients as well as healthy control subjects. The most likely source for the elevated CD34+ cell concentration in peripheral blood is progenitor cells of extra-medullar origin. more...

Between January 1985 and December 1992, 104 consecutive patients with symptomatic myelofibrosis with myeloid metaplasia (MMM) [splenic enlargement >5 cm and/or transfusional requirement or Hb <; 10 g/dl and/or white blood cell (WBC) count >20 x 10(9)/l and/or platelets >1.0 x 10(9)/l] received low-dose Melphalan (2.5 mg/3 times/week) to evaluate the efficacy and toxicity of this approach. Among 99 evaluable patients, 66 (66.7%) achieved a response after a median time of 6.7 months: 26 (26.3%) had a normalization of all clinical and haematological parameters (complete response, CR) and 40 (40.4%) showed an improvement >50% (partial response, PR). Thirty-three patients (33.3%) were resistant. Reversible haematological toxicity was the most common complication. Median durations of CR and PR were 28.4 and 26 months respectively: median survival of CR + PR patients was 71.2 months (95%CI: 33.8-108.7) versus 36.5 months (95%CI: 24.5-48.5) for the non-responders (log-rank test, P =0.002). In the multivariate analysis, the following variables were significantly associated with a shorter survival: anaemia [hazard risk (HR) = 2.7], WBC count >20 x 10(9)/l (HR = 2.4) and not achieving any type of response, either partial or complete (HR = 3.9). In conclusion, Melphalan could be a promising first-line option for MMM patients with clinical or haematological symptoms requiring treatment. more...

Idiopathic myelofibrosis is a myeloproliferative disease with poor prognosis and without sufficient therapy. Acute leukemic transformation occurs in 15% of patients. The authors report the case of a 63 year old myelofibrotic patient treated with splenectomy. During the clinical course they observed unusually prominent and persistent erythroblastosis in the peripherial blood. After a two years long, relatively stable period the disease terminated in acute myeloid leukemia. more...

The absolute content of CD34(+) cells in the peripheral blood of 84 patients with myelofibrosis with myeloid metaplasia (MMM) and 23 patients with other Philadelphia-negative (Ph(-)) chronic myeloproliferative disorders (CMDs) was investigated. In MMM, the median absolute number of circulating CD34(+) cells was consistently high (91.6 x 10(6)/L; range, 0-2460 x 10(6)/L). Receiver operating characteristic curve analysis showed that 15 x 10(6)/L as a decision criterion for CD34(+) cells produced an almost complete discrimination between MMM patients out of therapy and other Ph(-) CMDs (positive predictive value, 98.4%; negative predictive value, 85.0%). MMM patients with higher numbers of CD34(+) cells had a significantly longer disease duration (P =.019) and higher spleen volume index (P =.014), liver volume (P =.000), percentage of circulating immature myeloid cells (P =.020), and percentage of myeloid blasts (P =.000). When CD34(+) cells were correlated with the use of Dupriez risk stratification, CD34(+) cells increased significantly from low-risk (median, 68.1 x 10(6)/L) to intermediate-risk (median, 112.8 x 10(6)/L) and high-risk patients (median 666.1 x 10(6)/L) (F = 4.95; P =.009). When CD34(+) cells were correlated with a severity score on the basis of both myeloproliferative and myelodepletive characteristics of the disease, only the myeloproliferation index was significantly associated with CD34(+) cell level (F = 5.7; P =.000). Overall survival and interval to blast transformation from the time of CD34(+) cell analysis were significantly shorter in patients with more than 300 x 10(6)/L CD34(+) cells (P =.005 and.0005, respectively). In conclusion, the absolute number of CD34(+) circulating cells allows MMM to be distinguished from other Ph(-) CMDs; it is strongly associated with the extent of myeloproliferation and predicts evolution toward blast transformation. more...

Myelofibrosis with myeloid metaplasia (MMM) is a clonal disorder involving disregulation of angiogenesis and immunomodulatory mechanisms. Thalidomide (Thal) retains antiangiogenic, immunomodulatory and cytokine regulatory properties and recently it has been used successfully in multiple myeloma. Here, we report our experience in 10 MMM patients treated with Thal. Patients with agnogenic MMM treated in an early phase of the disease obtained significant benefits from the therapy and remain transfusion-free. In contrast, all secondary MMM failed to respond. These preliminary findings confirm that Thal plays a role in MMM therapy, although the efficacy in the different phases of the disease must be further evaluated. more...

Tryptases are serine proteases primarily expressed in mast cells. Normal blood basophils express only trace amounts of the enzyme. However, recent immunohistochemical studies have raised the possibility that neoplastic basophils express significant amounts of tryptase. In this study, tryptase expression was analyzed in normal and neoplastic basophils by immunoelectron microscopy using antitryptase monoclonal antibody G3. Basophils were obtained from patients with chronic myeloid leukemia (CML), idiopathic myelofibrosis (IMF), and myelodysplastic syndrome (MDS), and from healthy donors. Tryptase-immunoreactive material was detected in cytoplasmic granules of basophils in CML, IMF, and MDS. By contrast, normal basophils did not contain significant amounts of tryptase by immunoelectron microscopy. As assessed by reverse transcription-polymerase chain reaction, neoplastic basophils contained messenger RNA (mRNA) for alpha-tryptase, but no beta-tryptase mRNA. In summary, these data provide evidence that neoplastic basophils in CML, IMF, and MDS can express detectable amounts of tryptase. Therefore, tryptase should not be regarded as specific for mast cells when neoplastic myeloid cells are analyzed. more...