What are RBC-transfusion-dependence and -independence?

The term RBC-transfusion-dependence is widely-used by hematologists to describe a condition of severe anemia typically arising when erythropoiesis is reduced such that a person continuously requires ≥1 RBC-transfusions over a specified interval. Defining a person as RBC-transfusion-dependent has important implications in diverse hematological disorders especially because it strongly-correlated with decreased survival. Conversely, becoming RBC-transfusion-independent or receiving fewer RBC-transfusions over a specified interval is defined as improvement or response in many disease- and/or therapy-setting. Whether this correlates with improved survival is controversial. We used a structured expert-panel consensus panel process to define RBC-transfusion-dependence and -independence or improvement. We suggest these definitions may prove useful to persons studying or treating these diseases.

High-dose imatinib mesylate combined with vincristine and dexamethasone (DIV regimen) as induction therapy in patients with resistant Philadelphia-positive acute lymphoblastic leukemia and lymphoid blast crisis of chronic myeloid leukemia.

Imatinib combined with high-dose chemotherapy is now becoming the gold standard for treatment of Philadelphia chromosome-positive acute leukemias. However, in all studies imatinib dosage was tapered to 400-600 mg per day. We decided to initiate a clinical trial to evaluate an opposite strategy based on high-dose imatinib (800 mg per day) combined with a less intensive chemotherapeutic regimen (vincristine and dexamethasone), which we called the DIV induction regimen. Thirty-one patients (18 relapsing or refractory Ph+ acute lymphoblastic leukemias and 13 lymphoid blast crisis chronic myelogenous leukemias) were enrolled. Complete remission (CR) was obtained in 28 out of 30 assessable patients. The median bcr-abl/abl ratio after the induction course was 0.1%. Median time to neutrophil recovery was 21 days. Fungus infections were observed in six patients out of 31 and possibly related to dexamethasone. Neuropathy due to vincristine was noted in 14 cases. Nine out of 19 patients under 55 years received allogenic stem cell transplantation after a median time of 78 days post-CR. Patients older than 55 years experienced a 90% CR rate without additional toxicities, suggesting the DIV regimen may also be proposed as a front line therapy in older patients.

Burkitt lymphoma in adults: a prospective study of 72 patients treated with an adapted pediatric LMB protocol.

BACKGROUND: We conducted a phase II study to evaluate in 72 adult patients the efficacy of the intensive LMB chemotherapy regimen, previously reported by the Société Française d'Oncologie Pédiatrique for children with Burkitt lymphoma and L3 acute lymphoblastic leukemia. PATIENTS AND METHODS: Treatment began with a prephase (low-dose steroids, vincristine and cyclophosphamide), except in patients with low tumor burden. Group A (resected stage I and abdominal stage II disease) received three courses of vincristine, cyclophosphamide, doxorubicin and prednisone. Group B (not eligible for groups A or C) received five courses of chemotherapy comprising high-dose methotrexate, infusional cytarabine and intrathecal (IT) methotrexate. Group C (patients with central nervous system and/or bone marrow involvement with < 30% of blast cells) received eight courses containing intensified high-dose methotrexate, high-dose cytarabine, etoposide and triple IT injections. RESULTS: The 2 year event-free survival and overall survival rates for the 72 patients were 65% and 70%, respectively. Age > or = 33 years and high lactate dehydrogenase value were associated with a shorter survival. No response to COP was also associated with a poor outcome in group B. CONCLUSION: Patients with advanced-stage Burkitt lymphoma, including those with bone marrow and/or central nervous system involvement, can be cured with a short-term intensive chemotherapy regime tailored to the tumor burden.

Role of splenectomy in the treatment of myelodysplastic syndromes with peripheral thrombocytopenia: a report on six cases.

Thrombocytopenia is generally of central origin in MDS, but can be due to peripheral platelet destruction in some cases. We studied platelet lifespan in 61 MDS cases with platelets < 70,000/mm3 and marrow blasts < 10%. Nine of them (15%) had a major platelet lifespan reduction (< 3.5 days), and were considered for splenectomy. Three of them were not splenectomized due to rapid death, patient refusal and older age plus liver predominance of platelet sequestration, respectively. The remaining six patients (two females and four males, median age 50 years, range 32 to 65) were splenectomized 3 to 21 months after diagnosis. Before splenectomy, five of them had RA and one had CMML. Platelets counts ranged from 5000 to 30,000/mm3 and did not durably respond to other treatments. Three of the patients has a relapse of platelet counts, concomitantly required platelet transfusion due to recurrent blending, whereas three had anemia (two required erythrocyte transfusion) and four had neutropenia. Three months after surgery, platelet counts ranged from 55,000 to 160,000/mm3 (> 100,000/mm3 in four cases), no patient required platelet or erythrocyte transfusion, but there was no effect on neutrophil counts. Three patients had a relapse of platelet counts, concomitant with progression to AML in two of them, whereas the third relapsing case achieved normal platelet counts with further danazol. One patient died with normal platelet counts 12 months after splenectomy (from sepsis, probably related to neutropenia rather than splenectomy). Two patients remained with normal platelet counts 10 and 52 months after surgery. Our findings suggest that the mechanism of thrombocytopenia should be studied more often in 'low risk' MDS (i.e. with low bone marrow blast counts) with thrombocytopenia, as about 15% of them appear to have peripheral platelet destruction. Some of those patients may benefit from splenectomy.

Outcome is not improved by the use of alternating chemotherapy in elderly patients with aggressive lymphoma.

INTRODUCTION: A prospective randomised study involving 810 elderly patients was conducted in an attempt to compare alternating chemotherapy with conventional first-line chemotherapy in aggressive non-Hodgkin's lymphoma in order to improve prognosis with an acceptable toxicity for elderly patients. PATIENTS AND METHODS: Patients included were 55-69 years old and had at least one adverse prognostic factor. Patients were treated either with ACVBP followed by consolidation (n = 396) or with an alternating regimen (n = 414). This regimen was an association of active drugs in NHL relapsing patients, alternating VIMMM with ACVBP for induction and alternation of VIM and ACVM in consolidation. Eight hundred and sixty-six patients were randomised. After histological review, 810 patients met the inclusion criteria: 396 in arm A, 414 in arm B. RESULTS: The complete response rate after induction was superior for conventional first-line therapy (58.5% vs 48%, P = 0.003) but at the end of treatment, the CR rate was not statistically different (52% vs 48%, P = 0.19). Conventional chemotherapy had a better five-year event-free survival than alternating regimen (33% (95% CI: 30-36%) vs 28% (95% CI: 26-30%), P = 0.0289) but overall survival was not statistically different (40% (CI 95% 38-42%) vs 36% (CI 95% 34-38%), P = 0.068). In this elderly high risk population, the toxicity was very high: 19% in arm A and 26% in arm B died during treatment. CONCLUSION: Alternating regimen did not improve outcome, was less efficient and more toxic.

Randomized comparison of ACVBP and m-BACOD in the treatment of patients with low-risk aggressive lymphoma: the LNH87-1 study. Groupe d'Etudes des Lymphomes de l'Adulte.

PURPOSE: To compare a short intensified regimen followed by sequential consolidation therapy (doxorubicin, cyclophosphamide, vindesine, bleomycin, and prednisone [ACVBP]) to the standard regimen of methotrexate, bleomycin, cyclophosphamide, and etoposide (m-BACOD) in patients with low-risk aggressive lymphoma. PATIENTS AND METHODS: A total of 752 patients with intermediate- or high-grade lymphoma and no adverse prognostic factors (Eastern Cooperative Oncology Group performance status of 2 to 4, >/= two extranodal sites of disease, tumor burden >/= 10 cm in largest dimension, bone marrow or CNS involvement, Burkitt's or lymphoblastic subtypes) were registered. Of 673 eligible patients, 332 received ACVBP and 341 received m-BACOD. RESULTS: The complete remission rate was identical (86%) in the two groups. With a median follow-up duration of 7 years, the 5-year failure-free survival (FFS) rate was 65% in the ACVBP group and 61% in the m-BACOD group (P =.16). The 5-year overall survival rate was 75% in the ACVBP group and 73% in the m-BACOD group (P =.47). ACVBP was responsible for more severe and life-threatening infections (P <.01), but m-BACOD caused more pulmonary toxicity (P <.001). The number of treatment-related deaths did not differ between the two regimens. A multivariate analysis indicated that ACVBP was associated with a longer FFS in patients with two or three risk factors of the International Prognostic Index. CONCLUSION: In this population of patients with low-risk aggressive lymphoma, toxicities of the regimens are different, but the rates of response and survival are identical. The survival advantage of ACVBP over standard regimen in patients with advanced disease is suggested by this analysis but remains to be assessed in prospective studies specifically designed for this purpose.

p190 bcr-abl rearrangement: a secondary cytogenetic event in some chronic myeloid disorders?

BACKGROUND AND OBJECTIVE: A small number of chronic myeloproliferative disorders with hematologic features of chronic myelomonocytic leukemia (CMML) or atypical chronic myeloid leukemia and Ph1 chromosome with m-BCR rearrangement have been reported (p190 CMPD). We report here 3 new cases of p190 CMPD that had unusual features. In 2 of the cases the m-BCR rearrangement appeared to be a secondary event. DESIGN AND METHODS: Patients were studied by cytogenetic, FISH, and molecular biology analyses and followed-up clinically. RESULTS: The first patient initially had typical 5q- syndrome, without m-BCR rearrangement. Five years later, she developed hematologic features of CMML, with t(9;22) translocation, m-BCR rearrangement and high levels of p190 BCR-ABL transcript. The second patient initially had hematologic characteristics of chronic myeloid leukemia (CML) with t(9;22) translocation and m-BCR rearrangement but also other complex cytogenetic findings including 17p rearrangement. Monocytosis developed during the course of the disease. The third patient initially had agnogenic myeloid metaplasia (AMM). Five years later, while the hematologic characteristics were still those of AMM, a first karyotype showed a t(9;22) translocation and molecular analysis showed a very low level of p190 BCR-ABL transcript. Four years later, the patient developed hematologic features of atypical CML with blood monocytosis, t(9;22) and much greater (100 fold) p190 BCR-ABL transcript levels. INTERPRETATION AND CONCLUSIONS: Our 3 cases and review of the previously published cases show the variability of clinical features of p190 positive CMPD. Our results also suggest that, at least in some cases, p190 BCR-ABL rearrangement could be a secondary event in the course of a myeloid disorder.

The VIM3-AraC regimen followed by autologous stem cell transplantation in refractory or relapsing aggressive non-Hodgkin's lymphoma. A prospective study of 71 consecutive cases.

We evaluated with an intent-to-treat analysis the response rate, the disease-free survival (DFS), and the overall survival after a multidrug salvage regimen (VIM3ARAC), followed by stem-cell transplantation (SCT) in case of response, in patients with aggressive non-Hodgkin's lymphoma (NHL) who progressed on or after the first-line therapy. Seventy-one patients (refractory: 15; relapse 'on therapy': 36; and relapse 'off therapy': 20) received two courses of VIM3ARAC (teniposide, ifosfamide, mitoxantrone, mitoguazone, high-dose methotrexate, high-dose cytarabine, prednisolone). SCT was performed only in patients with minimal disease after the second course. The response rate was 72%. It was not influenced by response to first-line therapy. Forty-eight patients (68%), including 32 complete responders, fulfilled response criteria for SCT. Thirty-six patients underwent SCT (allogeneic: 3; autologous: 33). The 4-year DFS rate of the 48 responding patients was 39%. The actuarial survival at 4 years was 34% for all patients. Relapse off therapy and a performance status <2 at relapse were the only two independent favorable prognostic factors for survival. In conclusion, VIM3AraC is associated with a high response rate in relapsing and refractory aggressive NHL. Up to half of the patients could receive SCT. This chemotherapy, followed by SCT could durably salvage 34% of these patients.

[Molecular study of a false outbreak of ticarcillin-resistant Pseudomonas aeruginosa infections in a clinical hematology department]. / Etude moléculaire d'une pseudo-épidémie d'infections à Pseudomonas aeruginosa résistant à la ticarcilline dans un service d'hématologie clinique.

Molecular methods for bacterial strain typing are becoming available outside teaching hospitals and large structures. Although it seems reasonable to use conventional markers, most notably the serotype, whenever possible, the limitations of these methods are particularly conspicuous with P. aeruginosa. Combined use of several methods such as quantitative antibiotic susceptibility testing and serotype determination has proved adequate for characterizing P. aeruginosa strains in some cases. In the case of the outbreak reported herein, this approach failed to provide high quality epidemiological data. In contrast, pulsed field gel electrophoresis ruled out epidemic spread of a P. aeruginosa strain in the clinical hematology department.

Myelofibrosis with myeloid metaplasia in young individuals: disease characteristics, prognostic factors and identification of risk groups.

Myelofibrosis with myeloid metaplasia (MMM) is an uncommon disorder in young individuals, for whom haemopoietic stem cell transplantation offers the only possibility of cure. However, although the latter procedure is associated with significant morbidity and mortality, the clinical course of MMM is variable, with some patients surviving for less than a year and others showing an indolent course. Selection of young MMM patients for transplantation or other newer therapies is currently difficult since no prognostic data exists for this subgroup. In the present collaborative study a number of initial clinical and laboratory parameters have been evaluated for prognosis in 121 MMM patients aged 55 years or less. Median survival of the series was 128 months (95% CI 90-172). In the Cox proportional hazard regression model three initial variables were independently associated with shorter survival: Hb <10 g/dl (P <0.0001), the presence of constitutional symptoms (fever, sweats, weight loss) (P=0.001), and circulating blasts >/=1% (P=0.003). Based on the above three criteria, of the 116 patients with complete data, two groups were identified: a 'low-risk' group, characterized by 88 patients with up to one adverse prognostic factor, in whom MMM had an indolent course (median survival 176 months, 95% CI 130-188), and a 'high-risk' group, including 28 patients with two or three factors, who had a more aggressive disease (median survival 33 months, 95% CI 20-42). The above prognostic scoring system showed a high positive predictive value, sensitivity and specificity to predict survival in the series, and could be of help in making treatment decisions in young patients with MMM.

Elevated levels of basic fibroblast growth factor in megakaryocytes and platelets from patients with idiopathic myelofibrosis.

Idiopathic myelofibrosis, or agnogenic myeloid metaplasia, is a chronic myeloproliferative disorder characterized by clonal expansion and marrow fibrosis. Although marrow fibrosis appears to be a reactive process, it substantially contributes to impaired haemopoiesis. During the last few years the implication of megakaryocyte-derived growth factors in its pathogenesis has been documented. We previously reported increased expression of TGF-beta in patients with idiopathic myelofibrosis. In the present study we show that circulating megakaryocytic cells from such patients expressed high levels of basic fibroblast growth factor (bFGF). An increased expression of bFGF was also detected in patients' platelets. Under culture conditions, bFGF present in megakaryocytic cells was not exported into the medium. consistent with the fact that bFGF is devoid of a secretion peptide signal. Interestingly, this lack of bFGF secretion was observed in all patients but one, who was in an accelerated phase of the disease and presented an important percentage of circulating megakaryoblasts.

Placebo-controlled phase III study of lenograstim (glycosylated recombinant human granulocyte colony-stimulating factor) in aggressive non-Hodgkin's lymphoma: factors influencing chemotherapy administration. Groupe d'Etude des Lymphomes de l'Adulte.

The purpose of this study was to, assess the efficacy of glycosylated recombinant human granulocyte colony-stimulating factor (lenograstim) in the prevention of neutropenia and infection in patients receiving dose-intensive chemotherapy for non-Hodgkin's lymphoma (NHL). A second objective was to determine clinical predicators of delay to cytotoxic chemotherapy administration. One hundred-sixty two patients with intermediate- or high-grade NHL and at least one poor prognostic factor received a total of 4 cycles of the LNH-84-regimen every 2 weeks, with an open randomization to treatment with anthracyclines. Patients were randomized to receive subcutaneous lenograstim 5 micrograms/kg/day (n = 82) or placebo (n = 80) from day 6 to day 13 of each cycle. The incidence of severe neutropenia (absolute neutrophil count (ANC) < 0.5 x 10(9)/L) was reduced in the lenograstim group compared with placebo (52% vs 75%). A significant reduction (p < 0.001) in the median duration of ANC < 0.5 x 10(9)/L was also observed in patients treated with lenograstim during each cycle of chemotherapy (0-1 day vs 2-4 days in placebo recipients). Fever occurred in 66 patients in each treatment group. Thirty-four percent of placebo recipients had documented infections during ANC < 1.0 x 10(9)/L compared with 18.5% of lenograstim-treated patients (p < 0.05). Infections of > or = 2 severity were significantly less frequent (p = 0.001) among lenograstim recipients compared with placebo (25 vs 49). The most common adverse events among lenograstim recipients were headache, mild bone pain and injection site reactions. Although lenograstim significantly increased (p = 0.0001) relative dose intensity compared with placebo (93% vs 80%), no difference in CR rate (67% vs 71%) or 3-year survival (63% vs 55%) was observed. The results of this study suggest that patients treated with a chemotherapy regimen that induces severe neutropenia can benefit from treatment with lenograstim. Furthermore, lenograstim permits treatment to be delivered at full dose intensity at 2 week intervals, even in patients with bone marrow involvement, and may permit further dose escalation of the chemotherapeutic regimen used.

Benefit of autologous bone marrow transplantation over sequential chemotherapy in poor-risk aggressive non-Hodgkin's lymphoma: updated results of the prospective study LNH87-2. Groupe d'Etude des Lymphomes de l'Adulte.

PURPOSE: To update the randomized study that compared consolidative sequential treatment (ifosfamide, etoposide, asporaginase, and cytarabine) versus the high-dose regimen of cyclophosphamide, carmustine, and etoposide (CBV) followed by autotransplantation in patients with aggressive non-Hodgkin's lymphoma in first complete remission and to focus on high-intermediate and high-risk patients identified by the international prognostic index. PATIENTS AND METHODS: Nine hundred sixteen patients received induction treatment on the LNH84 protocol with open randomization for the anthracycline. In a subsequent randomization, 541 patients in complete remission were assigned to receive consolidation by either sequential chemotherapy (n = 273) or autotransplant (n = 268). Among the higher risk population (two or three risk factors), 236 patients in complete remission were assessable for the consolidation phase, with 111 in the sequential chemotherapy arm and 125 in the autotransplant arm. RESULTS: Among 541 randomized patients, disease-free survival and survival did not differ significantly between the two consolidative treatment arms. In the higher risk population, CBV was superior to sequential chemotherapy, with 5-year disease-free survival rates of 59% (95% confidence interval, 49% to 69%) and 39% (95% confidence interval, 28% to 50%), respectively (P = .01, relative risk = 1.19). The 5-year survival rate was superior in the CBV group at 65% (95% confidence interval, 56% to 74%) compared with 52% in the sequential chemotherapy group (95% confidence interval, 42% to 62%) (P = .06, relative risk = 1.49). CONCLUSION: This study shows a superior disease-free survival for higher risk patients in complete remission. Dose-intensive consolidation therapy should be considered for patients at higher risk who achieve complete remission after induction treatment.

Differential expression of transforming growth factor-beta, basic fibroblast growth factor, and their receptors in CD34+ hematopoietic progenitor cells from patients with myelofibrosis and myeloid metaplasia.

Myelofibrosis with myeloid metaplasia (MMM) is a myeloproliferative disorder characterized by clonal expansion of hematopoiesis and marrow fibrosis. Previous results from our group have shown an increased production of two potent fibrogenic factors also involved in the regulation of primitive hematopoietic cells, namely transforming growth factor-beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF), in patients with MMM. It is likely to assume that the myeloproliferation characteristic of this disease may result from an abnormal proliferation of CD34+ hematopoietic progenitors. Thus, we were particularly concerned in studying the gene and protein expression of these cytokines and their receptors in CD34+ progenitors purified from the peripheral blood of MMM patients by using semiquantitative reverse transcriptase-polymerase chain reaction and immunolabeling methods. Our data showed that the expression of TGF-beta1 is not altered in patients CD34+ cells; in contrast, the expression of TGF-beta type II receptor is significantly decreased in such cells, as compared with CD34+ cells from healthy subjects. Regarding bFGF, the very low expression of the cytokine and its type I and II receptors detected in normal CD34+ cells contrasts with that observed in patients' CD34+ cells, which is significantly higher. Our results might be a clue for a better understanding of the mechanism(s) involved in the dysregulation of hematopoiesis in MMM. Actually, the increased expression of bFGF and its receptors associated with the reduction of the TGF-beta binding receptor in CD34+ progenitors from MMM patients might facilitate the expansion of hematopoietic progenitors, not only by stimulating their growth and/or survival, but also by overcoming negative regulatory signals.

Prognostic factors in agnogenic myeloid metaplasia: a report on 195 cases with a new scoring system.

We studied the survival of 195 patients with agnogenic myeloid metaplasia (AMM) diagnosed between 1962 and 1992 in an attempt to stratify patients into risk groups. Median survival was 42 months. Adverse prognostic factors for survival were age > 60 years, hepatomegaly, weight loss, low hemoglobin level (Hb), low or very high leukocyte count (WBC), high percentage of circulating blasts, male sex, and low platelet count. A new scoring system based on two adverse prognostic factors, namely Hb < 10 g/dL and WBC < 4 or > 30 x 10(9)/L, was able to separate patients in three groups with low (0 factor), intermediate (1 factor), and high (2 factors) risks, associated with a median survival of 93, 26, and 13 months, respectively. An abnormal karyotype (32 cases of 94 tested patients) was associated with a short survival, especially in the low-risk group (median survival of 50 v 112 months in patients with normal karyotype). The prognostic factors for acute conversion were WBC > 30 x 10(9)/L and abnormal karyotype. Thus, hemoglobin level and leukocyte count provide a simple prognostic model for survival in AMM, and the adverse prognostic value of abnormal karyotype may be related to a higher rate of acute conversion.

Is the small non-cleaved-cell lymphoma histologic subtype a poor prognostic factor in adult patients? A case-controlled analysis. The Groupe d'Etude des Lymphomes de l'Adulte.

PURPOSE: To study the prognostic significance of the small non-cleaved-cell lymphoma (SNCCL) histologic subtype, we compared the outcome of adult patients with SNCCL with that of patients with aggressive lymphoma other than SNCCL by means of two case-controlled studies. PATIENTS AND METHODS: We analyzed the results of the doxorubicin, cyclophosphamide, vindesine, bleomycin, and prednisone (ACVBP) regimen used as a reference scheme in our cooperative study group (Groupe d'Etude des Lymphomes de l'Adult [GELA]) in 52 adult SNCCL patients with no bone marrow (BM) or CNS involvement. Forty-five SNCCL patients younger than 60 years could be compared with two separate case-matched groups of patients with aggressive lymphoma other than SNCCL undergoing the same therapeutic regimen. In the first case-controlled study, matching ensured identity of each risk factor of the age-adjusted International Index (ie, Ann Arbor stage, performance status, and lactate dehydrogenase [LDH] level); in the second study, matching was performed according to the number of presenting risk factors (zero, one, two, or three), regardless of their nature. RESULTS: The 5-year overall survival rates were not significantly different between SNCCL and control patients in both case-controlled studies: 48% versus 51% in the first study, and 48% versus 55% in the second study. CONCLUSION: These results support the thesis that in patients with no bone marrow or CNS involvement, the SNCCL histologic subtype does not confer a prognosis worse than that of other aggressive lymphoma.

Autologous bone marrow transplantation as consolidation therapy may prolong remission in newly diagnosed high-risk follicular lymphoma: a pilot study of 34 cases.

We evaluated early intensification followed by autologous bone marrow transplantation (ABMT) using marrow purged by mafosfamide in patients with high-risk low-grade follicular lymphoma (LGFL) reaching a status of minimal disease (MD). Thirty-four patients entered the program. All fulfilled at least one of the following criteria at diagnosis: a bulky tumor > 7 cm; three or more adenopathies > 3 cm; massive pleural or peritoneal effusion; massive splenomegaly; B symptoms; platelet count < 100 x 10(9)/l. Twenty-one patients had bone marrow involvement. Twenty-six patients received ACVBP, and eight CVP as front-line therapy. Twenty-one (62%) patients achieved MD status, 18 reached intensification. At 4 years, the time to treatment failure is 55 +/- 9%, and the probability of persisting remission is 75 +/- 11%. Comparison by intention to treat of the 26 patients who received ACVBP as front-line therapy to 14 historical high-risk LGFL similarly treated in our institution without intensification, showed better results for the intensified group (P = 0.04 for both probability of persisting remission and time to treatment failure). These results indicate that early intensification using marrow purged with mafosfamide is a therapeutic option which may bring benefit to patients with high-risk LGFL.

Transforming growth factor-beta and megakaryocytes in the pathogenesis of idiopathic myelofibrosis.

Although the disease is well described, the pathogenesis of bone marrow fibrosis in idiopathic myelofibrosis still remains unclear. We previously reported elevated intraplatelet transforming growth factor-beta (TGF-beta) levels in patients with this myeloproliferative disorder, compared with healthy subjects. Here, in a series of 16 patients, we show that TGF-beta expression is also increased in patients' peripheral blood mononuclear cells (PBMC): (i) at the mRNA level analysed by Northern blot hybridization and/or reverse transcription-polymerase chain reaction (RT-PCR); (ii) and/or at the secreted peptide level as evaluated in conditioned media from patients' mononuclear cells by a growth inhibition assay on CC164 cells. By immunostaining with a polyclonal anti-TGF-beta 1 antibody, TGF-beta was localized in morphologically heterogenous cells; these cells were characterized as megakaryocytes by labelling with a gpIIbIIIa monoclonal antibody. Thus we provide evidence that both TGF-beta and megakaryocytes are linked in the pathogenesis of idiopathic myelofibrosis.