Myelofibrosis in chronic myeloproliferative disorders--dynamics and clinical impact

In chronic myeloproliferative disorders, presenting or evolving myelofibrosis (MF) is associated with significant morbidity and mortality. A systematically conducted evaluation of previous studies and data from our own material reveals a strikingly expressed heterogeneity of findings. Assessment of MF should be performed by a recently established semiquantitative scoring system regarding quantity and quality (reticulin versus collagen). It is important to differentiate between a fiber increase in bone marrow specimens and the clinical diagnosis that is explicitly based on extramedullary hematopoiesis (myeloid metaplasia). For this reason, prodromal stages of (reticulin) fibrosis are overlooked by the clinicians. Up to 30% of patients with chronic myelogenous leukemia show a minimal to advanced MF that is significantly associated not only with corresponding clinical parameters but more importantly with prognosis. In polycythemia vera about 20% of patients may display some degree of reticulin fibrosis at diagnosis, depending on stage of the disease. Transformation into (collagen) MF after more than 10 years is accompanied by clinical signs of myeloid metaplasia (spent phase). Essential thrombocythemia (ET) is characterised by the absence of increased reticulin at onset and an insignificant progression into MF, provided diagnosis is performed by the WHO criteria. Discrimination of prefibrotic and early stages of chronic idiopathic myelofibrosis (CIMF) from ET is relevant, especially concerning the rate and time usually required for the development of MF with myeloid metaplasia (full-blown CIMF). In conclusion, more elaborate evaluations including standardized grading of MF is warranted by regarding bone marrow biopsy specimens in association with clinical parameters including follow-up examinations.

Monitoring of the JAK2-V617F mutation by highly sensitive quantitative real-time PCR after allogeneic stem cell transplantation in patients with myelofibrosis

The JAK2-V617F mutation occurs in about 50% of patients with myelofibrosis and might be a reliable marker to monitor residual disease after allogeneic stem cell transplantation. We describe a new, highly sensitive (>or= 0.01%) real-time polymerase chain reaction (PCR) to monitor and quantify V617F-JAK2-positive cells after dose-reduced allogeneic stem cell transplantation. After 22 allogeneic stem cell transplantation procedures in 21 JAK2-positive patients with myelofibrosis, 78% became PCR negative. In 15 of 17 patients (88%), JAK2 remained negative after a median follow-up of 20 months. JAK2 negativity was achieved after a median of 89 days after allograft (range, 19-750 days). A significant inverse correlation was seen for JAK2 positivity and donor-cell chimerism (r:-0.91, P<.001). Four of 5 patients who never achieved JAK2 negativity fulfilled during the entire follow-up all criteria for complete remission recently proposed by the International Working Group, suggesting a major role for JAK2 measurement to determine depths of remission. In one case, residual JAK2-positive cells were successfully eliminated by donor lymphocyte infusion. In conclusion, allogeneic stem cell transplantation after dose-reduced conditioning induces high rates of molecular remission in JAK2-positive patients with myelofibrosis, and quantification of V617F-JAK2 mutation by real-time PCR allows the detection of minimal residual disease to guide adoptive immunotherapy.

Different outcome of allogeneic transplantation in myelofibrosis using conventional or reduced-intensity conditioning regimens

Allogeneic haematopoietic stem cell transplantation remains the only curative treatment of myelofibrosis with myeloid metaplasia (MMM). Previous reports have indicated significant treatment-related mortality (TRM) for patients transplanted after myeloablative conditioning but superior survival has been reported after reduced-intensity conditioning (RIC). We report the results of a survey of all allogeneic transplantations for MMM performed in Sweden at six transplant units between 1982 and 2004. Twenty-seven patients were transplanted; 17 with a myeloablative conditioning regimen and 10 with RIC. The median age was 50 years (5-63 years) at transplantation. After a median follow up of 55 months, 20 patients are alive. TRM was 10% in the RIC group and 30% in the myeloablative group. There was no difference in survival for high or low-risk patients according to Cervantes score or between sibling and unrelated donor transplantations.

The impact of clinicopathological studies on staging and survival in essential thrombocythemia, chronic idiopathic myelofibrosis, and polycythemia rubra vera

In chronic myeloproliferative disorders (MPDs), varying results regarding staging of disease and assessment of outcome have been reported. Risk classification is mainly based on clinical data; however, in those disorders associated with an elevated platelet count, discrimination of (true) essential thrombocythemia (ET) may be difficult without the possibility to recognize characteristic histopathological bone marrow patterns according to the World Health Organization (WHO) guidelines. Patients with ET reveal no relevant reduction of life expectancy and the impact of disease is significantly higher in elderly patients, especially in chronic idiopathic myelofibrosis (IMF) and polycythemia rubra vera (PV). In high-risk ET, the overall incidence of myelofibrotic transformation after 36 months of follow-up is 2.8% when considering the Polycythemia Vera Study Group guidelines. In contrast, classification according to WHO fails to show a relevant transformation into myelofibrosis either by clinical or morphological standards in (true) ET. Early stages of IMF show a more favorable outcome, but in multivariate risk classification, signs of myeloid metaplasia have the most important impact on prognosis. In PV, the risk for thrombosis increases with age, and furthermore, signs of generalization are generally associated with a worsening of prognosis. It has been shown that examination of bone marrow specimens enhances the diagnostic reliability and also enables the recognition of evolving myelofibrotic transformation in MPDs.

Palliative goals, patient selection, and perioperative platelet management: outcomes and lessons from 3 decades of splenectomy for myelofibrosis with myeloid metaplasia at the Mayo Clinic

BACKGROUND

Although splenectomy may palliate massive splenomegaly in patients with myelofibrosis with myeloid metaplasia, this procedure carries significant risks. The authors retrospectively analyzed their experience with splenectomy over the course of 30 years to analyze the impact of improved techniques, antimicrobials, and aggressive postoperative control of platelet counts on outcome.

METHODS

A total of 314 patients underwent splenectomy between 1976 and 2004 for mechanical symptoms (= 156 patients [49%]), anemia (= 78 patients [25%]), portal hypertension (= 47 patients [15%]), or thrombocytopenia (= 33 patients [11%]). Of a total of 91 patients studied during the last decade, 69 patients (76%) experienced a palliative benefit for their primary surgical indication for a median of 12 months (range, 1-91 months).

RESULTS

Perioperative complications occurred in 87 patients (27.7%) including infection (= 31 patients [9.9%]), thrombosis (= 31 patients [9.9%]), or bleeding (= 44 patients [14%]), 21 of which (6.7% of all patients) were fatal. Perioperative thrombohemorrhagic complications decreased in the last decade through the use of platelet apheresis and the prompt use of cytoreductive agents to counteract postsplenectomy thrombocytosis. Survival after splenectomy was found to be decreased in patients with preoperative thrombocytopenia (<100 x 10(9)/L [P = 0.006]) but not by indication, myelofibrosis with myeloid metaplasia (MMM) prognostic score, or the decade in which splenectomy was performed.

CONCLUSIONS

The lack of improvement in overall postsplenectomy survival over time may be a reflection on the failure of medical therapy to improve survival in patients with MMM.

Presence of unfavorable cytogenetic abnormalities is the strongest predictor of poor survival in secondary myelofibrosis

BACKGROUND

Postpolycythemic (PV) and postthrombocythemic (ET) myeloid metaplasia are consensually referred to as secondary myelofibrosis (sMF). Prognostic variables in sMF are not as well defined as they are for de novo myelofibrosis with myeloid metaplasia (MMM), which is also known as agnogenic myeloid metaplasia (AMM). Such information is particularly crucial for management decisions in transplant-eligible patients.

METHODS

Diagnoses of PV and ET required fulfillment of the World Health Organization criteria for the diagnosis of MMM as well as an antecedent history of either polycythemia vera or essential thrombocythemia that was supported by bone marrow examination. Cytogenetic findings were classified as being either favorable (normal or isolated 13q- or 20q- clones) or unfavorable (presence of abnormalities other than 13q- and 20q-).

RESULTS

The study population was comprised of 66 young patients (age <60 yrs) with sMF, including 37 patients with PV and 29 patients with ET. Multivariate analysis of parameters other than cytogenetics identified older age (P = .02), anemia (hemoglobin level <10 g/dL [P = .007]), and PV (P = .009) to be independent risk factors for shortened survival. However, when such analysis was restricted to patients in whom cytogenetic studies were performed (n = 31 patients), the presence of unfavorable cytogenetic abnormalities (i.e., clones other than 20q- and 13q-) became the only adverse prognostic factor for survival (P = .001). A similar analysis in a temporal cohort of 50 age-matched patients with AMM also identified unfavorable cytogenetics as an independent predictor of poor survival, along with thrombocytopenia and anemia.

CONCLUSIONS

The results of the current study suggest that cytogenetic findings might supersede AMM-derived prognostic scoring systems for predicting survival in patients with sMF.

Microcytosis in agnogenic myeloid metaplasia: Prevalence and clinical correlates

Microcytosis is a characteristic laboratory feature for both iron deficiency anemia and thalassemia. It is also infrequently seen in "anemia of chronic disease" that accompanies a spectrum of chronic conditions including rheumatoid arthritis, polymyalgia rheumatica, diabetes mellitus, connective tissue disease, and protracted infection. In addition, there is a well established but pathogenetically obscure association of microcytosis with Hodgkin's lymphoma, Castleman's disease, and renal cell carcinoma. In the current study, we show that microcytosis is a frequent laboratory feature in agnogenic myeloid metaplasia and investigate its clinical relevance in the particular setting.

Prognostic relevance of cytogenetics determined by fluorescent in situ hybridization in patients having myelofibrosis with myeloid metaplasia

BACKGROUND

In chronic myelofibrosis (MF), distinct recurrent cytogenetic aberrations have been identified but their true prognostic relevance remains uncertain. In this disease, cytogenetic studies as assessed by conventional metaphase karyotyping are limited due to the inherent difficulties in obtaining adequate bone marrow aspirates and the low proliferative capacity of the clonal cells. Interphase fluorescent in situ hybridization (FISH) can partly overcome these limitations and increase the sensitivity of cytogenetic assessment in MF.

METHODS

We retrospectively analyzed formalin-fixed, paraffin embedded bone marrow sections of 107 MF patients by FISH and correlated cytogenetic findings with clinical presentation and survival.

RESULTS

Chromosomal aberrations were detected in 56% of patients, with 20q- (24.3%) and 13q- (16.8%) being the most frequent ones. Importantly, cytogenetic abnormalities were found in 8/17 patients displaying a normal karyotype as assessed by conventional cytogenetics.

CONCLUSIONS

Cytogenetic abnormalities in patients with MF can be detected reliably using FISH. Rare abnormalities confer an adverse outcome, but the main recurrent chromosomal aberrations do not correlate with clinical features and prognosis.

V617F mutation in JAK2 is associated with poorer survival in idiopathic myelofibrosis

Most patients with polycythemia vera and half with idiopathic myelofibrosis and essential thrombocythemia have an acquired V617F mutation in JAK2. Using sensitive polymerase chain reaction (PCR)-based methods, we genotyped 152 patients with idiopathic myelofibrosis to establish whether there were differences in presentation and outcome between those with and those without the mutation. Patients positive for V617F had higher neutrophil and white cell counts (P = .02) than did patients negative for V617F, but other diagnostic features were comparable between the 2 groups. Patients positive for V617F were less likely to require blood transfusion during follow-up (P = .03). Despite this, patients positive for V617F had poorer overall survival, even after correction for confounding factors (P = .01).

Adult acute megakaryocytic leukemia: an analysis of 37 patients treated at M.D. Anderson Cancer Center

To characterize acute megakaryocytic leukemia (FAB M7 AML), we identified 37 patients with M7 AML treated at M.D. Anderson Cancer Center between 1987 and 2003 and compared them with 1800 patients with non-M7, non-M3 AML treated during the same period. The median age of the M7 AML group was 56 years (range, 21-78 years); 22 patients (59%) had an antecedent hematologic disorder or myelodysplastic syndrome or both, and 7 patients (19%) had previously received chemotherapy for other malignancies. Extensive bone marrow fibrosis was found in 23 patients (62%). Poor cytogenetic characteristics were observed in 49% of patients with M7 AML versus 33% of others (P < .001). Complete remission rates were 43% with M7 AML and 57% with non-M7 AML (P = .089). Median overall survival (OS) was 23 and 38 weeks, respectively (P = .006). Median disease-free survivals were 23 versus 52 weeks, respectively (P < .001). By multivariate analysis, M7 AML was an independent adverse prognostic factor for OS, independent of other factors including cytogenetic abnormalities (hazard ratio 1.51, P = .049). These results confirm the poor prognosis of M7 AML and indicate that other biologic characteristics beyond cytogenetic abnormalities likely play a role in this disease.

Hematopoietic Stem Cell Transplantation for Myelofibrosis

Myelofibrosis with myeloid metaplasia (MMM) is a clonal disorder resulting from the proliferation of aberrant hematopoietic progenitors. Hence MMM is curable if the abnormal clone can be eradicated and replaced by normal cells from healthy donors. Myeloablative allogeneic transplantation results in high rates of durable engraftment and cure in approximately 50% of patients. Treatment-related mortality rather than disease recurrence accounts for the majority of treatment failures. Higher rates of treatment failure are associated with more advanced disease and age. More recently, nonmyeloablative (reduced-intensity) conditioning regimens have been shown to induce encouraging rates of engraftment and prolonged survival. When recommending transplantation for a particular patient, the prospect of cure should be weighed against the considerable risks of the procedure. Transplantation is typically recommended for patients under the age of 50 years with intermediate- and high-risk features, or for patients aged 50 to 60 years with an anticipated survival of less than 5 years. Finally, autologous transplantation has also been evaluated as a potential treatment approach. This procedure is unlikely to be curative, but might have a palliative role.

Myelofibrosis With Myeloid Metaplasia: Diagnosis, Prognostic Factors, and Staging

Myelofibrosis with myeloid metaplasia (MMM) is an infrequent disease usually affecting elderly people. Due to the lack of a specific marker for MMM, efforts are being made to refine the diagnostic criteria. A prefibrotic form of the disease has recently been recognized and a set of diagnostic criteria proposed by the Italian Consensus Conference for the Diagnostic Criteria of MMM. Moreover, the number of circulating CD34(+) cells has recently been proven to be useful in the differential diagnosis of the disease. Median survival of patients with MMM is about 5 years, but there is wide variability. Hemoglobin level at diagnosis is the most important prognostic factor, whereas age, constitutional symptoms, low or high leukocyte counts, blood blast cells, cytogenetic abnormalities, and number of circulating CD34(+) cells are also of prognostic value. Based on some of the above factors, several prognostic systems of MMM have been proposed to identify at presentation subgroups of patients with a different risk profile. This is especially important in younger individuals, who may benefit from therapies that have curative potential but also involve a mortality risk (notably, allogeneic hemopoietic stem cell transplantation). Since no disease-oriented therapies for MMM are currently available and treatment is based on palliation and improvement of quality of life, therapy should be formulated according to the form of presentation of the disease and its prognostic implications. A staging system for MMM that meets treatment requirements and available therapeutic resources should be developed by considering parameters able to predict not only survival but also other disease outcomes, such as development of anemia, thrombocytopenia, splenomegaly, and blast transformation. Such a staging system should be derived from a large population of patients, systematically collected from diagnosis without selection bias and followed over time.

Pilot study of reduced-intensity conditioning followed by allogeneic stem cell transplantation from related and unrelated donors in patients with myelofibrosis

A prospective pilot study was performed to evaluate the effect of reduced-intensity conditioning with busulphan (10 mg/kg), fludarabine (180 mg/qm) and anti-thymocyte globulin followed by allogeneic stem cell transplantation from related (n = 8) and unrelated donors (n = 13) in 21 patients with myelofibrosis. The median age of the patients was 53 years (range, 32-63). No primary graft failure occurred. The median time until leucocyte (>1.0 x 10(9)/l) and platelet (>20 x 10(9)/l) engraftment was 16 (range, 11-26) and 23 d (range, 9-139) respectively. Complete donor chimaerism on day 100 was seen in 20 patients (95%). Acute graft-versus-host disease (GvHD) grades II-IV and III/IV occurred in 48% and 19% of cases and 55% of the patients had chronic GvHD. Treatment-related mortality was 0% at day 100 and 16% [95% confidence interval (CI): 0-32%] at 1 year. Haematological response was seen in 100% and complete histopathological remission was observed in 75% of the patients and 25% of the patients showed partial histopathological remission with a continuing decline in the grade of fibrosis. After a median follow-up of 22 months (range, 4-59), the 3-year estimated overall and disease-free survival was 84% (95% CI: 67-100%).

Peripheral blood CD34 count in myelofibrosis with myeloid metaplasia: a prospective evaluation of prognostic value in 94 patients

In a prospective study, peripheral blood (PB) CD34 count, bone marrow histology and other clinical parameters were concurrently evaluated in 94 patients with myelofibrosis with myeloid metaplasia (MMM) and the study cohort followed for a minimum of 3 years. Median PB CD34 count was 0.0547 x 10(9)/l (range 0-5.345 x 10(9)/l) with 86% of the patients displaying above normal levels (>0.005 x 10(9)/l). In a multivariate analysis, only leucocyte count and PB blast percentage correlated with PB CD34 count in an independent and consistent fashion. After a median follow up of 41 months from PB CD34 analysis, 43 patients (46%) have died with a projected 5-year survival of 50%. In a univariate analysis, PB CD34 count above 0.1 x 10(9)/l correlated significantly with shortened survival, leukaemic transformation and clinical progression. However, such statistical significance was lost during multivariate analysis, which identified only anaemia and leucocytosis as independent risk factors for shortened survival. Furthermore, sequential analysis of PB CD34 count was performed in 53 patients and 43% of those who progressed clinically did not display a concomitant rise in their PB CD34 count. The current prospective study does not support an independent prognostic value for PB CD34 count in MMM.

Outcome of allogeneic stem cell transplantation in patients with myelofibrosis

Myelofibrosis, either de novo or following pre-existing hematologic diseases, can be cured by allogeneic hematopoietic stem cell transplantation (SCT), but SCT is associated with significant morbidity and mortality, making the choice and timing of transplantation difficult. In all, 20 patients (seven female and 13 male), with a median age of 45 years (range 22-57 years), with idiopathic myelofibrosis (n = 12), post-thrombocythemic (n = 3) or post-polycythemic (n = 2) myeloid metaplasia or leukemic transformation (n = 3), underwent allogeneic SCT at our center between 1994 and 2003. With regard to the pre-transplant presence of risk factors such as hemoglobin levels < or =10 mg/dl, grade III marrow fibrosis or peripheral blast counts >1%, patients were divided into high- and low-risk groups. The estimated 3-year survival post transplant was 38.5% for all patients. The 3-year probability of survival within the high-risk group (n = 11) characterized by the presence of at least two risk factors was 16%. Low-risk patients (n = 9) with at most one risk factor had an estimated 3-year survival of 67%. Thus, previously defined risk determinants for the outcome of allogeneic transplantation for myelofibrosis may provide useful information facilitating treatment strategies. Our data suggest that transplantation should be taken into consideration before poor prognostic variables develop.

Myelofibrosis with myeloid metaplasia: new developments in pathogenesis and treatment

Myeloid metaplasia with myelofibrosis (MMM) is a chronic myeloproliferative disorder (CMPD) characterized by progressive anemia, massive splenomegaly, both hepatosplenic and non-hepatosplenic extramedullary hematopoiesis (EMH), a leukoerythroblastic blood smear, circulating progenitor cells, and marked bone marrow stromal reaction including collagen fibrosis, osteosclerosis and angiogenesis. The overall median survival is 5 years although it might range from 2 to 15 years depending on the presence or absence of clinically defined prognostic factors. Death is often due to leukemic transformation, portal hypertension or infection. In addition to shortened survival, quality of life is often affected by frequent red blood cell transfusions, profound constitutional symptoms, and cachexia. Drug therapy and autologous hematopoietic stem cell transplantation (HSCT) are of only palliative value and have not been shown to improve survival. The role of allogeneic HSCT, both myeloablative and non-myeloablative, is actively being investigated. Both splenectomy and radiation therapy have defined therapeutic roles to control EMH-associated symptoms. Analysis of the molecular biology of the disease is underway with the aid of animal models leading to the identification of novel therapeutic targets. Among the novel agents tested, thalidomide seems the most promising although newer agents are on the horizon.

Angiogenesis in chronic myeloproliferative diseases detected by CD34 expression

Increased bone marrow angiogenesis estimated as bone marrow microvessel density (MVD), or as serum angiogenic factor levels and/or immunohistochemical expression of these factors in bone marrow biopsy has been demonstrated in a variety of hematological disorders including chronic myeloproliferative diseases (MPDs). The aim of this study was to investigate the MVD in 25 cases of myelofibrosis with myeloid metaplasia (MMM). MVD was estimated by CD34 immunohistochemical expression in bone marrow biopsies. A control group of 27 patients without bone marrow disease, eight cases of polycythemia vera (PV), 41 cases of essential thrombocythemia (ET) and nine cases of chronic myeloid leukemia (CML) were also studied. Moreover, in cases with MMM, MVD was correlated with clinical, laboratory, histological parameters and the outcome of the patients. Our study confirmed a significantly higher degree of angiogenesis in MMM, PV, ET and CML compared with controls (P < 0.001, P = 0.0007, P < 0.001 and P = 0.0008, respectively). Angiogenesis was higher in MMM than PV, ET and CML cases (P < 0.001, P < 0.001 and P = 0.008). Increased angiogenesis was correlated with hypercatabolic symptoms in MMM patients (P = 0.009). No correlation with other clinicopathological parameters or clinical outcome was found. However, definitive conclusions regarding the prognostic value of increased angiogenesis may require additional follow-up and a larger group of patients.

[Choice of therapy and overall survival in patients with chronic myeloproliferative diseases]

A retrospective analysis of 106 case histories of primary chronic myeloproliferative diseases (CMPD) was undertaken: idiopathic myelofibrosis--71 (67%), polycythemia vera--29 (27.3%), and essential thrombocythemia--6 (5.7%), median age--65 years (26-84 yrs). Hydroxyurea and myelosan were mostly used as cytostatic drugs while erythrocyte mass transfusions and hemoexfusions (phlebotomy)--for life-support. Median overall survival in patients untreated with cytostatics was 95.2 years as compared with 156 months in recipients of such drugs. Survival rates in all CMPD patients with hypocellular bone marrow who had received cytostatics were lower than in those with normal or hypercellular marrow (p=0.005). Cytostatic therapy had either no impact on survival in patients with hypocellular bone marrow or was followed by decrease. Among CMPD patients who had received erythrocyte mass transfusions survival rates were significantly lower than in intact ones (p=0.0009). Median overall survival in patients receiving hemoexfusions was 193.6 months, as compared with 110.3 months in intact ones (p=0.008). Our data may be useful in selecting therapy for CMPD.

Thrombotic thrombocytopenic purpura associated with bone marrow metastasis and secondary myelofibrosis in cancer

To examine the relationship between cancer and development of thrombotic microangiopathy (TM), the medical records of patients with known TM were examined in one institution from January 1981 to December 2002. Nine out of 93 patients with the established diagnosis of TM had active cancer. All nine of those patients had thrombotic thrombocytopenic purpura (TTP). Among those patients, two patients received chemotherapy prior to the development of TTP. Six of the seven patients who received no chemotherapy had extensive bone marrow metastasis and secondary myelofibrosis. There were two patients each with breast cancer, lung cancer, and stomach cancer. Severe anemia and thrombocytopenia with leukoerythroblastosis were prominent clinical features in all six patients. Four patients had neurological (mental) changes and three developed fever, but none had significant renal dysfunction. Upon establishing the diagnosis of TTP, four patients were treated with exchange plasmapheresis (EP) and two patients were treated with chemotherapy because there were no neurological changes. Three patients achieved complete remission of TTP, one with EP alone and two with chemotherapy. The one patient who achieved remission with EP alone was later treated with chemotherapy and survived for 2 1/2 years. The other three patients treated with EP alone died within 2 months after the diagnosis of TTP. Since TTP occurred in association with bone marrow metastasis and myelofibrosis in six patients among seven chemotherapy-untreated cancer patients, this marrow change was considered to be the possible cause of the development of TTP. It is recommended that all cancer patients with unexplained anemia and thrombocytopenia be evaluated for the coexistence of bone marrow metastasis and TTP.

Allogeneic hematopoietic stem cell transplantation for myelofibrosis

Fifty-six patients, 10 to 66 years of age, with idiopathic myelofibrosis (IMF) or end-stage polycythemia vera or essential thrombocythemia received allogeneic hematopoietic cell transplants from related (n = 36) or unrelated (n = 20) donors. Forty-four patients were prepared with busulfan plus cyclophosphamide and 12 with total body irradiation plus chemotherapy. The source of stem cells was marrow in 33 and peripheral blood in 23 patients. All but 3 patients achieved engraftment. While 50 patients showed complete donor chimerism, 3 patients were found to be mixed chimeras at 26, 48, and 86 months after transplantation, respectively. Two patients died from relapse/progressive disease, and 18 died from other causes. There are 36 patients surviving at 0.5 to 11.6 (median, 2.8) years, for a 3-year Kaplan-Meier estimate of 58% (CI, 43%-73%). Dupriez score, cytogenetic abnormalities, and degree of marrow fibrosis were the most significant risk factors for posttransplantation mortality. Patients conditioned with a regimen of busulfan targeted to plasma levels of 800 to 900 ng/mL plus cyclophosphamide had a higher probability of survival (76% [CI, 62%-91%]) than other patients. Results with unrelated donors were comparable with those with HLA-identical sibling transplants. Thus, allogeneic hematopoietic cell transplantation offers long-term relapse-free survival for patients with myelofibrosis.

Circulating hematopoietic progenitor cells predict survival in patients with myelofibrosis with myeloid metaplasia

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.

[Prognostic value of bone marrow biopsy in chronic myeloproliferative disorders]

The aim of the present research was to verify the prognostic value of some histologic bone marrow parameters in chronic myeloproliferative disorders. Diagnostic bone marrow biopsies were revised in 38 patients with chronic myeloid leukaemia, 30 with polycythemia vera, 14 with essential thrombocythemia and 16 with idiopathic myelofibrosis-myeloid metaplasia. An unfavourable clinical evolution was associated to "granulocytic" histotype in chronic myeloid leukaemia, to "erythrocytic/granulocytic and/or megacaryocytic" histotype in polycythemia vera, to "cluster" distribution of megacaryocytes in essential thrombocythemia, to classical myelofibrosis without osteomyelosclerosis in myelofibrosis-myeloid metaplasia. Bone marrow biopsy in chronic myeloproliferative disorders provides independent diagnostic and prognostic data; we support its routine execution in this group of hematologic malignancies.

Stem cell transplantation for myelofibrosis: a report from two Canadian centers

We describe the course of 25 patients with myelofibrosis (MF) due to agnogenic myeloid metaplasia (n=19) or essential thrombocytosis (n=6) who underwent allogeneic stem cell transplantation (SCT) at one of two Canadian centers. The median age at transplantation was 48.7 (IQR 45.9-50.4) years and transplantation was carried out at a median of 10.7 (IQR 5.67-26.5) months after diagnosis. Granulocyte engraftment (absolute neutrophil count >0.5 x 109/l) occurred at a median of 20 days after transplantation for splenectomized patients, compared with 27.5 days for nonsplenectomized individuals (P=0.03). Increased risk of grade II-IV acute graft-versus-host disease (P=0.04) was noted in patients transplanted after splenectomy. Patients with MF received 0.264+/-0.189 U of packed red blood cells per day over the first 180 days after transplantation, and remained dependent on red blood cell transfusions for a median of 123 (IQR 48-205) days. Complete remission of MF was documented in 33% of evaluable patients. The 1 year cumulative nonrelapse mortality was 48.3%. Median survival for this group of patients was 393 (IQR 109-1014+) days, with a projected 2-year overall survival of 41%. We conclude that allogeneic SCT offers a reasonable chance for prolonged survival in patients with advanced MF, but this occurs at the cost of considerable toxicity and nonrelapse mortality.

Karyotypic abnormalities in myelofibrosis following polycythemia vera

Polycythemia vera (PV) is a chronic myeloproliferative disease characterized by an increase of total red cell volume; in 10% to 15% of cases, bone marrow fibrosis complicates the course of the disease after several years, resulting in a hematologic picture mimicking myelofibrosis with myelocytic metaplasia (MMM). This condition is known as post polycythemic myelofibrosis (PPMF). Among 30 patients with PPMF followed in Northern France, 27 (90%) expressed one or two abnormal clones in myelocytic cell cultures. Of these, 19 (70%) had partial or complete trisomy 1q. This common anomaly either resulted from unbalanced translocations with acrocentric chromosomes, that is, 13, 14, and 15, or other chromosomes, that is, 1, 6, 7, 9, 16, 19, and Y, or from partial or total duplication of long arm of chromosome 1. A single patient had an isochromosome 1q leading to tetrasomy 1q. In all cases, a common trisomic region spanning 1q21 to 1q32 has been identified. Given that most patients had previously received chemotherapy or radio-phosphorus to control the polycythemic phase of their disease, this study illustrates the increased frequency of cytogenetic abnormalities after such treatments: 90% versus 50% in de novo MMM. Moreover, karyotype can be used to distinguish PPMF-where trisomy 1q is the main anomaly-from primary MMM where trisomy 1q is rare and deletions 13q or 20q are far more common. Whether trisomy 1q is or is not a secondary event remains a matter of debate, as well as the role of cytotoxic treatments.