Myeloproliferative disease in transgenic mice expressing P230 Bcr/Abl: longer disease latency, thrombocytosis, and mild leukocytosis

P230 Bcr/Abl has been associated with indolent myeloproliferative disease (MPD). We generated transgenic mice expressing P230Bcr/Abl driven by the promoter of the long terminal repeat of the murine stem cell virus of the MSCV neo P230 BCR/ABL vector. Two founder mice exhibited mild granulocytosis and marked thrombocytosis and developed MPD. The disease of one founder mouse, no. 13, progressed to extramedullary myeloblastic crisis in the liver at 12 months old. The other founder mouse, no. 22, was found to have chronic-phase MPD with large populations of megakaryocytes and granulocytes in an enlarged spleen. The transgenic progeny of no. 22 clearly exhibited MPD at 15 months old. These results showed that P230Bcr/Abl had leukemogenic properties and induced MPD. The phenotype of the MPD caused by P230Bcr/Abl was characterized by mild granulocytosis, a high platelet count, infiltration of megakaryocytes in some organs, and a longer disease latency compared with the MPD caused by P210Bcr/Abl.

Bone marrow biopsy morbidity and mortality

A postal survey of adverse events associated with bone marrow biopsy (aspiration biopsy with or without trephine biopsy) was carried out among British Society of Haematology members, between 1995 and 2001. A total of 26 adverse events, including one death directly attributable to the procedure, were reported among an estimated 54 890 biopsies. The most frequent and most serious adverse event was haemorrhage, reported in 14 patients, necessitating blood transfusion in six patients and leading to the single death. The potential risk factors most often associated with haemorrhage were a diagnosis of a myeloproliferative disorder, aspirin therapy or both. Other potential risk factors were warfarin therapy, disseminated intravascular coagulation and obesity.

Acquired von Willebrand Syndrome: Its Pathophysiology, Laboratory Features and Management

Acquired von Willebrand syndrome is a bleeding disorder associated with various underlying diseases. The clinical manifestations are similar to congenital von Willebrand disease. Diagnosis is mainly confirmed by decrease of ristocetin cofactor activity (vWF:RCo) and collagen binding activity (vWF:CBA) and by vWF multimeric analysis usually with selective loss of large multimers. Various pathogenic mechanisms have been proposed, including development of autoantibodies to von Willebrand factor (vWF), adsorption of vWF onto tumor cells or activated platelets, increase of vWF proteolysis, and mechanical destruction of vWF under high shear stress. Following the treatment of underlying disorders, desmopressin (DDAVP) is a first intention therapeutic option. Factor VIII/vWF concentrates and high dose immunoglobulin infusions are reserved for patients unresponsive to DDAVP.

Myeloproliferative syndromes and the associated risk of coronary artery disease

INTRODUCTION

Of the major myeloproliferative syndromes (MPS) [polycythemia vera (PV), essential thrombocythemia (ET), chronic myeloid leukemia (CML) and myelofibrosis (MF)], PV and ET are reported to be associated with increased thrombotic complications. However, the relationship between these myeloproliferative syndromes and coronary artery disease (CAD) is unclear.

METHODS

We performed a retrospective chart review to evaluate the prevalence of CAD in patients with diagnosed with MPS between 1991 and 2001.

RESULTS

One hundred and eighty-one patients (100 males, 81 females) with a mean age of 72.5 years were included. Twenty-nine patients, 19 males and 10 females (16%, 95% CI: 12.0-24.0) had CAD. These included 6/53 (11.3%, 95% CI: 1.5-20.2) patients with CML, 1/26 (3.8%, 95% CI: -4.4 to 12.8) patients with PV, 5/30 (16.7%, 95% CI: 2.5-30.8) patients with ET, 3/7 (42.9%, 95% CI: 12.3-87.7) patients with MF and 14/65 (21.5%, 95% CI: 13.1-37.8) patients with co-existent MPS. Comparing the risk of CAD with CML as a baseline, MF had an OR of 8.2 (p < 0.01, 95% CI: 1.7-39), PV-0.4 (p = 0.4, 95% CI: 0.04-3.2), ET-1.6 (p = 0.7, 95% CI: 0.43-6.2) and patients with co-existent MPS-2.8 (p=0.07, 95% CI: 0.91-8.6). However, after adjusting for age, sex, dyslipidemia, diabetes, hypertension and tobacco use, the difference in the prevalence of CAD between the various categories of MPS was not significant.

CONCLUSION

Contrary to conventional belief, we did not find an increased prevalence of CAD in patients with either PV or ET. In fact, patients with MF had a significantly higher prevalence of CAD. However, this difference appears to be due to the increased age at diagnosis of MF. The conventional risk factors for CAD appear to be the major determinants of CAD among patients with MPS.

Stimulation of osteoprotegerin production is responsible for osteosclerosis in mice overexpressing TPO

Myelofibrosis and osteosclerosis are prominent features arising in mice overexpressing thrombopoietin (TPO). The pivotal role of transforming growth factor beta 1 (TGF-beta 1) in the pathogenesis of myelofibrosis has been documented, but the mechanisms mediating osteosclerosis remain unclear. Here, we used mice deficient in osteoprotegerin (OPG), a secreted inhibitor of bone resorption, to determine whether osteosclerosis occurs through a deregulation of osteoclastogenesis. Marrow cells from opg-deficient mice (opg(-/-)) or wild-type (WT) littermates were infected with a retrovirus encoding TPO and engrafted into an opg(-/-) or WT background for long-term reconstitution. The 4 combinations of graft/host (WT/WT, opg(-/-)/opg(-/-), opg(-/-)/WT, and WT/opg(-/-)) were studied. Elevation of TPO and TGF-beta 1 levels in plasma was similar in the 4 experimental groups and all the mice developed a similar myeloproliferative syndrome associated with severe myelofibrosis. Osteosclerosis developed in WT hosts engrafted with WT or opg(-/-) hematopoietic cells and was associated with increased OPG levels in plasma and decreased osteoclastogenesis. In contrast, opg(-/-) hosts exhibited an osteoporotic phenotype and a growth of bone trabeculae was rarely seen. These findings suggest that osteosclerosis in mice with TPO overexpression occurs predominantly via an up-regulation of OPG in host stromal cells leading to disruption of osteoclastogenesis.

Substance p-fibronectin-cytokine interactions in myeloproliferative disorders with bone marrow fibrosis

Bone marrow (BM) fibrosis could occur secondarily to several clinical disorders: hematological and nonhematological. Clinical presentation of fibrosis could occur in myeloproliferative diseases, lymphoma, myelodysplastic syndrome and myeloma. The pathophysiology underlying BM fibrosis remains unclear despite intensive study, with a corresponding lack of specific therapy. This review discusses new insights in the role of substance P, cytokines and fibronectin in the development of BM fibrosis. Substance P is a neuropeptide that possesses pleiotropic properties, e.g. neurotransmission and immune/hematopoietic modulation and is linked to BM fibrosis. Cytokines and growth factors, in particular those associated with fibrogenic properties, e.g. TGF-beta, IL-1 and platelet-derived growth factor, are linked to BM fibrosis. Extracellular matrix proteins are increased in patients with BM fibrosis. Fibronectin in the sera of patients with BM fibrosis is complexed to substance P. Fibronectin appears to protect substance P from degradation by endogenous peptidases. This review describes the preliminary findings on the colocalization of substance P and fibronectin in the BM of patients with fibrosis. These data are reviewed in the context of published reports with particular focus on the relevant cytokines. A more detailed understanding of intra- and intercellular mechanisms in BM fibrosis may lead to effective therapy.

Isolated pericardial effusion in the human fetus: a report of three cases

OBJECTIVE

Our objective was to determine the possible underlying etiologies and outcome in isolated fetal pericardial effusion.

METHODS

Doppler fetal echocardiography allowed the diagnosis of pericardial effusion in three patients and revealed the etiology in two.

RESULTS

We present the findings in three cases of isolated pericardial effusion. In the first, the pericardial effusion was a manifestation of trisomy 21 associated with a myeloproliferative disorder. In the second, the pericardial fluid collection was the first sign of an autosomal recessive disease, idiopathic infantile arterial calcification. The third case was remarkable because of the spontaneous resolution of a large pericardial fluid collection.

CONCLUSION

Isolated fetal pericardial effusion covers a wide spectrum of etiologies from severe genetic and chromosomal diseases to transient forms.

[Mesenteric and splenic vein thrombosis in a female patient with essential thrombocytosis and activated protein C resistance]

Splenic venous thrombosis is a rare disease in which an underlying hypercoagulable state can often be found. A 27-years old female patient with recurrent mesenteric venous and splenic thrombosis as a severe complication of an association of resistance to activated protein C and essential thrombocythemia is presented in this report. Establishing the diagnosis of essential thrombocytosis was particularly difficult because this was the case of the so called "silent" myeloproliferative disorder. The number of thrombocytes was almost normal before the splenectomy performed because of the splenic venous thrombosis. Thus, spontaneous growth of erythroid and megakaryocyte colonies in vitro and the clinical course of the disease were the clues for establishing the diagnosis, because the number of thrombocytes reached the values over 1500 x 10(9)/l after only 1.5 years of the follow-up. The case of this patient was interesting particularly from the surgical point of view because of the management strategy.

Chronic myeloproliferative disorders with thrombocythemia: a comparative study of two classification systems (PVSG, WHO) on 839 patients

A multicenter observational study was performed on 839 adult patients with a chronic myeloproliferative disorder and a platelet count in excess of 600 x 10(9)/l to compare the updated criteria of the Polycythemia Vera Study Group (PVSG) with the recently published WHO classification. Essential thrombocythemia (ET) was diagnosed in 483 patients according to the PVSG; however, when considering histopathology as a major diagnostic feature of the WHO criteria, (true) ET could be established in only 162 patients. The remaining cases were found to represent either initially prefibrotic (184 patients) or early fibrotic (137 patients) chronic idiopathic myelofibrosis (IMF). On the other hand, both classification systems enabled a clear-cut distinction of patients showing overt IMF and polycythemia vera. Follow-up examinations in 140 patients with ET according to the PVSG criteria included also sequential bone marrow biopsies (interval: 38+/-30 months). A transition into mild reticulin fibrosis occurred in only 2 of 49 patients with (true) ET in contrast to 45 of 91 patients with initial and early IMF where a progression into overt myelofibrosis was encountered. Survival patterns for ET displayed significant differences because according to the PVSG a 16.5% disease-specific loss of life expectancy was calculable compared to a value of only 8.9% when following the WHO criteria. Contrasting this finding, initial and early IMF mimicking ET was characteriZed by a reduction of life expectancy ranging between 21.6% and 32.3 %. In conclusion, a more accurate classification of ET is warranted by regarding the WHO criteria that include histopathology as a major feature for diagnosis.

Diagnosis and management of acquired von Willebrand syndrome

The acquired von Willebrand syndrome is a rare bleeding disorder with laboratory finding similar to those of congenital von Willebrand's disease. Unlike the congenital form, however, the acquired syndrome usually occurs in persons with no personal or family history of bleeding. Large-scale studies are not available, diagnosis is still difficult, and treatment is empirical. Published findings and an international registry indicate that the syndrome is especially frequent in lympho- or myeloproliferative disorders; therefore, it should be suspected when there is excessive bleeding in patients with these disorders. Acquired von Willebrand syndrome is also associated with solid tumors, immunologic and cardiovascular, disorders. Diagnosis is based on assays measuring ristocetin cofactor activity or collagen binding; these levels are usually abnormally low, while factor VIII coagulant activity can be normal. Factor VIII/von Willebrand factor-inhibiting activities are found in only a minority of cases. Bleeding episodes in patients with the syndrome are mostly of the mucocutaneous type and can be managed with desmopressin, plasma-derived factor VIII/von Willebrand factor concentrates, and intravenous immunoglobulin. Recombinant activated factor VII, plasmapheresis, corticosteroids, and immunosuppressors combined with chemotherapy are also useful in some cases. Acquired von Willebrand syndrome, although rare, warrants further understanding for clinical practice.

The evolution of juvenile myelomonocytic leukemia in a female patient with paternally inherited neurofibromatosis type 1

The most common myeloid malignancy seen in children with neurofibromatosis type 1 (NF-1) is juvenile myelomonocytic leukemia (JMML), a myeloproliferative disease. The vast majority of these children have inherited the neurocutaneous disease from an affected mother; boys are more often affected than girls. We present the rare finding of a 7-year-old girl with NF-1 who developed JMML. She inherited her NF-1 from the father. At the time of her initial presentation, clonogenic assays of bone marrow mononuclear cells did not show the spontaneous growth of granulocyte-macrophage colony-forming units or hypersensitivity to granulocyte-macrophage colony-stimulating factor that is characteristic of this disorder. After 1 month, repeat evaluations of the patient's clinical and laboratory test results became fully consistent with those for a diagnosis of JMML. This illustrates the stepwise evolution of this myeloproliferative disorder in NF-1 and the importance of close follow-up and reassessment of these patients. Our case is only the second report of JMML in a girl who inherited NF-1 from her father.

Thrombophilic genotypes, natural anticoagulants, and plasma homocysteine in myeloproliferative disorders: relationship with splanchnic vein thrombosis and arterial disease

The contribution of pro-thrombotic factors towards the development of arterial disease (AD) and splanchnic vein thrombosis (SVT) was retrospectively evaluated in 79 patients (39M, 40F, mean age 55 +/- 16 years) with myeloproliferative disorders (MPD) (essential thrombocythemia [n = 26], primary proliferative polycythemia [n = 27], and idiopathic myelofibrosis [n = 26]). Of these, 18 had AD and 17 SVT, the remaining 44 were non-thrombotic (NT). Plasma concentrations of natural anticoagulants, plasma homocysteine (HC), IgG anticardiolipin antibodies (aCL), and thrombophilic genotypes (methylenetetrahydrofolate reductase C(677)T, factor V Leiden, prothrombin G(20210)-->A) were determined. Isolated protein C deficiency was found in 23% of patients from the SVT group, in 5% from the AD group, in 6.8% from the NT group, and in 1% of historical controls (P = 0.0001). The prevalence of thrombophilic genotypes and that of the other natural anticoagulants did not differ across the groups. The proportion of patients with elevated plasma HC was 66% in the AD group, 27% in the non-thrombotic group, 12% in the SVT group and 4.5% in the control group (P < 0.0001). Patients with AD had higher plasma HC (24.4 +/- 23 micromol/L) than NT patients (12.3 +/- 7.7 micromol/L), SVT patients (9 +/- 4.9 micromol/L), and healthy controls (7.9 +/- 3 micromol/L) (P < 0.0001). In a logistic regression model lower protein C was independently associated with SVT, whereas elevated plasma HC was independently associated with AD. Measurement of plasma HC and protein C in MPD may identify patients more likely to suffer arterial disease and splanchnic vein thrombosis and who may require plasma HC lowering in the former case.

Chronic myeloproliferative disorders

The Philadelphia chromosome-negative chronic myeloproliferative disorders (CMPD), polycythemia vera (PV), essential thrombocythemia (ET) and chronic idiopathic myelofibrosis (IMF), have overlapping clinical features but exhibit different natural histories and different therapeutic requirements. Phenotypic mimicry amongst these disorders and between them and nonclonal hematopoietic disorders, lack of clonal diagnostic markers, lack of understanding of their molecular basis and paucity of controlled, prospective therapeutic trials have made the diagnosis and management of PV, ET and IMF difficult. In Section I, Dr. Jerry Spivak introduces current clinical controversies involving the CMPD, in particular the diagnostic challenges. Two new molecular assays may prove useful in the diagnosis and classification of CMPD. In 2000, the overexpression in PV granulocytes of the mRNA for the neutrophil antigen NBI/CD177, a member of the uPAR/Ly6/CD59 family of plasma membrane proteins, was documented. Overexpression of PRV-1 mRNA appeared to be specific for PV since it was not observed in secondary erythrocytosis. At this time, it appears that overexpression of granulocyte PRV-1 in the presence of an elevated red cell mass supports a diagnosis of PV; absence of PRV-1 expression, however, should not be grounds for excluding PV as a diagnostic possibility. Impaired expression of Mpl, the receptor for thrombopoietin, in platelets and megakaryocytes has been first described in PV, but it has also been observed in some patients with ET and IMF. The biologic basis appears to be either alternative splicing of Mpl mRNA or a single nucleotide polymorphism, both of which involve Mpl exon 2 and both of which lead to impaired posttranslational glycosylation and a dominant negative effect on normal Mpl expression. To date, no Mpl DNA structural abnormality or mutation has been identified in PV, ET or IMF. In Section II, Dr. Tiziano Barbui reviews the best clinical evidence for treatment strategy design in PV and ET. Current recommendations for cytoreductive therapy in PV are still largely similar to those at the end of the PVSG era. Phlebotomy to reduce the red cell mass and keep it at a safe level (hematocrit < 45%) remains the cornerstone of treatment. Venesection is an effective and safe therapy and previous concerns about potential side effects, including severe iron deficiency and an increased tendency to thrombosis or myelofibrosis, were erroneous. Many patients require no other therapy for many years. For others, however, poor compliance to phlebotomy or progressive myeloproliferation, as indicated by increasing splenomegaly or very high leukocyte or platelet counts, may call for the introduction of cytoreductive drugs. In ET, the therapeutic trade-off between reducing thrombotic events and increasing the risk of leukemia with the use of cytoreductive drugs should be approached by patient risk stratification. Thrombotic deaths seem very rare in low-risk ET subjects and there are no data indicating that fatalities can be prevented by starting cytoreductive drugs early. Therefore, withholding chemotherapy might be justifiable in young, asymptomatic ET patients with a platelet count below 1500000/mm(3) and with no additional risk factors for thrombosis. If cardiovascular risk factors together with ET are identified (smoking, obesity, hypertension, hyperlipidemia) it is wise to consider platelet-lowering agents on an individual basis. In Section III, Dr. Gianni Tognoni discusses the role of aspirin therapy in PV based on the recently completed European Collaboration on Low-dose Aspirin in Polycythemia Vera (ECLAP) Study, a multi-country, multicenter project aimed at describing the natural history of PV as well as the efficacy of low-dose aspirin. Aspirin treatment lowered the risk of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke (relative risk 0.41 [95% CI 0.15-1.15], P =.0912). Total and cardiovascular mortality were also reduced by 46% and 59%, respectively. Major bleedings were slightly increased nonsignificnsignificantly by aspirin (relative risk 1.62, 95% CI 0.27-9.71). In Section IV, Dr. Giovanni Barosi reviews our current understanding of the pathophysiology of IMF and, in particular, the contributions of anomalous megakaryocyte proliferation, neoangiogenesis and abnormal CD34(+) stem cell trafficking to disease pathogenesis. The role of newer therapies, such as low-conditioning stem cell transplantation and thalidomide, is discussed in the context of a general treatment strategy for IMF. The results of a Phase II trial of low-dose thalidomide as a single agent in 63 patients with myelofibrosis with meloid metaplasia (MMM) using a dose-escalation design and an overall low dose of the drug (The European Collaboration on MMM) will be presented. Considering only patients who completed 4 weeks of treatment, 31% had a response: this was mostly due to a beneficial effect of thalidomide on patients with transfusion dependent anemia, 39% of whom abolished transfusions, patients with moderate to severe thrombocytopenia, 28% of whom increased their platelet count by more than 50 x 10(9)/L, and patients with the largest splenomegalies, 42% of whom reduced spleen size of more than 2 cm.

Non-invasive ventilation and palliation: experience in a district general hospital and a review

Non-invasive ventilation (NIV) is increasingly being used in hospitals to treat respiratory failure. The use of NIV with palliative intent in a district general hospital is described and ten illustrative cases where NIV was used in an attempt to palliate symptoms or to 'buy time' are presented. The role of NIV in relieving symptoms in various conditions is reviewed and ethical aspects are considered. It is suggested that hospital palliative care teams will increasingly see patients treated by this technique as it becomes more widely used for exacerbations of chronic obstructive airways disease, for relief of breathlessness in the terminally ill and for buying time in patient management. Domiciliary teams will see increasing numbers of people with motor neurone disease and other conditions treated with NIV.

Hepatic circulatory diseases associated with chronic myeloid disorders

These liver diseases are diseases of the hepatic circulation. Myeloproliferative disorders are among the most common prothrombotic disorders that lead to Budd-Chiari syndrome and PVT. SOS, previously known as hepatic veno-occlusive disease, is mainly seen in North America and Western Europe as a complication of the conditioning regimen for hematopoietic stem cell transplantation. SOS is caused by damage to SECs, and the initiating circulatory blockage occurs because of the embolism of sinusoidal lining cells. Myeloproliferative disorders are an uncommon cause of NRH, which is believed to be caused by uneven perfusion of the liver at the venous or sinusoidal level. Peliosis hepatis is believed to result from damage to SECs and is seen mainly in immunosuppressed patients, patients with a wasting illness, or patients with a drug toxicity.

[Anagrelide-induced changes of megakaryopoiesis during therapy of chronic myeloproliferative disorders with thrombocythemia]

Thrombocythemia in the course of chronic myeloproliferative disorders like chronic idiopathic myelofibrosis (cIMF) and of course essential thrombocythemia (ET), are characterized by life-threatening complications. In a number of clinical trials the recently introduced drug Agrylin((R)) has proven to be very effective. The normalization of the platelet count was related to an interference with megakaryocyte maturation leading to a left-shifting of this cell lineage and/or a reduced proliferation. However, until now no systematic study has been performed on the relationship between development of megakaryopoiesis and proliferative activity. In this investigation we included 10 patients with cIMF and 5 patients with ET that had received Agrylin((R)) for a period ranging between 6 and 70 months. Following therapy this cohort revealed a decrease in the platelet count from 1,104x10(9)/l at diagnosis to 485x10(9)/l. In this context we focused on an immunohistochemical and morphometric analysis of the CD61(+) megakaryopoiesis involving also endomitotic reduplication, by applying a double-immune incubation technique with the proliferating cell nuclear antigen (PCNA). Moreover, we determined the changes of fiber density during observation time. According to our results, the thrombocytopenic effect of Agrylin((R)) is based on an arrest in the dynamics of megakaryocyte maturation towards large (mature) platelet-shedding (polyploid) cells. This pathomechanism causes a significant increase in the number of promegakaryoblasts and megakaryoblasts. On the other hand, the total amount of CD61(+) megakaryocytic cells is not increased. Related to the peculiar cell biology of endomitotic reduplication during the maturation process and its different periods alloted to each single step, PCNA activity (late G1- and S-phase of the cell cycle) is found to be enhanced in the megakaryocyte precursors. Finally, no significant influence of Agrylin((R)) on the evolution of myelofibrosis is detectable and there is a general improvement of hematological data especially in cIMF.

Nephrotoxicity and purpura associated with levofloxacin

OBJECTIVE

To report a patient with lung cancer and idiopathic myelofibrosis with myeloid metaplasia who developed purpura and acute renal failure while receiving levofloxacin, and review the existing literature on quinolone nephrotoxicity.

CASE SUMMARY

A 73-year-old white man, with a medical history of non-small-cell lung cancer and idiopathic myelofibrosis with myeloid metaplasia, was prescribed levofloxacin because of a lower urinary tract infection. Three days later, he presented with palpable purpura and erythematous skin lesions over the lower limbs and trunk, with a markedly reduced urinary output. Serum creatinine and urea nitrogen were 6.4 and 190 mg/dL, respectively. Levofloxacin was discontinued, and prednisone, furosemide, and intravenous fluids were given. The patient fully recovered over the ensuing 4 weeks.

CONCLUSIONS

Nephrotoxicity associated with levofloxacin is uncommon. Allergic interstitial nephritis or vasculitis is believed to be the underlying pathologic process. Definitive diagnosis requires performance of renal biopsy, although this is not always feasible. In this case, a return of renal function to normal, with the disappearance of purpura following the discontinuation of levofloxacin and corticosteroid treatment, supports the presumptive diagnosis of a hypersensitivity reaction to levofloxacin.