Degree Of Bone Marrow Fibrosis Research Articles

Primary Myelofibrosis In Children

AbstractAbstract 3079Primary myelofibrosis is a chronic myeloproliferative disorder characterized by cytopenias, leukoerythroblastosis, extramedullary hematopoiesis, hepatosplenomegaly and bone marrow fibrosis. It is a serious medical condition in adults, often requiring major interventions such as hematopoietic stem cell transplantation (HSCT) for cure. In comparison to adults, children are rarely affected by this entity; the largest case series reports on four such patients. Most of these reports suggest that the majority of affected children have spontaneous resolution of their myelofibrosis with no long term complications. To better describe the clinical characteristics and outcomes of pediatric primary myelofibrosis, we performed a retrospective chart review of children diagnosed with myelofibrosis by bone marrow pathology at our institution from 1996 to 2009. Eighteen patients with primary myelofibrosis were identified. At presentation, all patients had one or more cytopenias and only one had leukoerythroblastosis. Three of 11 patients tested (27%) had cytogenetic abnormalities, as opposed to up to two-thirds of adults with primary myelofibrosis. Eleven of 18 patients (61%) demonstrated erythroid hypoplasia in the bone marrow, which is uncommon in adults. Based on recent molecular studies of myeloproliferative disorders in adults, the World Health Organization now includes the presence of a clonal marker such as JAK2V617F as a major criterion for diagnosis of myelofibrosis in adults. In contrast to approximately half of adults (43-63%) with primary myelofibrosis, JAK2V617F mutation in the bone marrow has not been reported in children. JAK2V617F mutation analysis was negative on 16 of 18 bone marrow specimens tested. In this series, only 5 of the 18 children (27.8%) had spontaneous recovery. No child developed malignant transformation. Eight children underwent HSCT, four of whom were cured of their myelofibrosis; the remaining four children died from infections acquired during transplantation. Four children died prior to transplantation, or were identified as having myelofibrosis at autopsy. One child transferred care to another facility and thus outcome data was not available. In all children, infection was the most common cause of death. Notably, the degree of bone marrow fibrosis did not correlate with outcome. Our series demonstrates that children with primary myelofibrosis have hematologic, bone marrow and molecular features that differ from adults. In contrast to what is found in the literature, our series of pediatric patients with primary myelofibrosis, the largest reported thus far, indicates a poor outcome for the majority of these patients. Disclosures:No relevant conflicts of interest to declare.

Allogeneic stem cell transplantation for myelodysplastic syndromes with bone marrow fibrosis

Bone marrow fibrosis in patients with myelodysplastic syndrome is associated with a poor outcome, but whether the outcome after allogeneic stem cell transplantation is related to the degree of bone marrow fibrosis is unknown. Patients with myelodysplastic syndrome and known bone marrow histology (n=721) who underwent hematopoietic stem cell transplantation were classified according to the degree of bone marrow fibrosis into those without fibrosis (n=483), those with mild or moderate fibrosis (n=199) and those with severe fibrosis (n=39) and analyzed regarding engraftment, treatment-related mortality, relapse and survival. The degree of fibrosis was not associated with disease status or abnormal cytogenetics. The cumulative incidence of engraftment achieved at day +30 in non-fibrotic patients was 93% and was significantly lower in those with mild or moderate fibrosis (89%) and severe fibrosis (75%) (P=0.009). Neutrophil engraftment occurred later in patients with mild or moderate fibrosis and severe fibrosis than in patients without fibrosis (median 17 versus 20 versus 16 days, respectively; P=0.002). The cumulative incidence of relapse at 3 years was significantly higher in patients with severe fibrosis than in those with a lesser degree of fibrosis or no fibrosis (47% versus 28% versus 27%, respectively; P=0.04), resulting in comparable 3-year disease-free survival rates in patients without fibrosis and in those with mild or moderate fibrosis (42% versus 38%, respectively) but a lower disease-free survival rate in those with severe fibrosis (18%; P=0.002). Severe fibrosis remained an independent factor for reduced survival (hazard ratio, 1.9; P=0.006). Among patients with myelodysplastic syndromes, only severe fibrosis affects survival after hematopoietic stem cell transplantation while patients with mild or moderate fibrosis have an outcome comparable to that of patients without bone marrow fibrosis.

Enhanced histone deacetylase enzyme activity in primary myelofibrosis

We measured histone deacetylase (HDAC) activity in 17 patients with primary myelofibrosis (PMF); 19 with other myeloproliferative neoplasm (MPN) and 16 normal volunteers. Significantly elevated HDAC levels were shown in patients with PMF compared with other MPN patients and normal volunteers (p < 0.05). Sixteen patients with PMF were also studied for correlation between JAK2 mutation status and HDAC levels; no significant correlation was found. We further correlated HDAC levels with clinical features in PMF: there was no correlation with WBC, platelet counts, Hb levels or degree of bone marrow fibrosis, but HDAC levels were correlated to the degree of splenomegaly. This suggests that HDAC may be recruited as essential thrombocythemia or polycythemia vera progresses into myelofibrosis or PMF progresses into more advanced stage. We then used the qRT-PCR cycle threshold (CT) method to study which HDACs were elevated in PMF. The results showed that, in general, Class 1 HDACs were elevated (HDAC1,2,8) except HDAC3, Class II HDACs were depressed (HDAC4,5) except HDAC6 and 10, and Class III HDACs were generally elevated. The current study may form the basis for using HDAC inhibitor in the treatment of patients with PMF and may implicate a possible role of HDAC in the association of pathogenesis of PMF.

The expression of CXCR4 is down-regulated on the CD34+ cells of patients with myelofibrosis with myeloid metaplasia

Purpose: We studied the expression of the chemokine receptor CXCR4 on circulating CD34+ cells of patients with myelofibrosis with myeloid metaplasia (MMM), and examined its relationship to the severity of disease. Patients and methods: Surface and intracellular CXCR4 expression were measured flow cytometrically in 84 consecutive MMM patients, 16 patients with polycythemia vera (PV), and 20 healthy subjects. In 23 MMM patients, CXCR4 gene expression level was also quantitated by real time-RT-PCR in CD34+ cells. Results: The expression of CXCR4 on circulating CD34+ cells was significantly reduced in patients with MMM ( P < 0.001) as compared to normal controls and patients with PV ( P = 0.01). The levels of CXCR4 mRNA in CD34+ cells were lower in patients with MMM as compared with normal subjects, and were directly correlated with the degree of CXCR4 surface expression, demonstrating that transcriptional defects were the major cause for receptor down-regulation. No statistical association was found between JAK2V617F mutational status and the extent of CXCR4 down-regulation. CXCR4 expression on CD34+ cells inversely correlated with the number of circulating CD34+ cells ( R = − 0.55; P < 0.001), and was severely down-regulated in high risk patients and patients with a high “myelodepletion severity index”. CXCR4 down-regulation was associated with advanced patient age, the presence of severe anemia, thrombocytopenia, and degree of bone marrow fibrosis. Conclusions: Reduced expression of CXCR4 by CD34+ cells is a characteristic of MMM which is associated with the constitutive mobilization of CD34+ cells and occurs in patients with advanced forms of the disease.

Quantitative Analysis of Growth Factor Production in the Mechanism of Fibrosis in Agnogenic Myeloid Metaplasia.

There are previous reports that growth factors including TGF-β1, PDGF and FGF produced by megakaryocytes are responsible for the etiology of fibrosis in agnogenic myeloid metaplasia (AMM). Due to the technical difficulty in isolating enough megakaryocytes from the inaspirable bone marrow from patients with AMM, a quantitative analysis of these growth factors produced by the megakaryocytes and correlated to the degree of myelofibrosis has not been able to be performed. The present study employed the cell culture technique to grow megakaryocytes from blood CD 34+ cells and then perform the quantitative analysis of these growth factors, compared with other sources such as monocyte-macrophage lineages and correlated to the degree of bone marrow fibrosis. We found TGF-β1, PDGF and FGF produced by the megakaryocytes were significantly elevated in AMM compared with normal controls (p<0.05) and TGF-β1 was more abundantly produced than PDGF or FGF. While these growth factors are several fold elevated in AMM compared with other MPD including essential thrombocythemia (ET), polycythemia vera (PV), it was not statistically significant. A quantitative analysis of these growth factors produced by the CD 14+ cells in the blood and bone marrow showed that these growth factors were not significantly elevated in AMM compared with other MPD or controls and were significantly elevated only in some patients (defined as elevation of more than 2 SD of the controls). The correlation of these growth factors produced by the megakaryocytes or monocyte-macrophage lineages with degree of myelofibrosis in 12 patients with AMM were r=0.73 and 0.23 respectively (Non parametric (Spearman) correlation with two-tailed analysis was used to calculate the correlation). We concluded:In AMM, these fibrosing growth factors are mainly produced by the megakaryocytes and in some patients, monocyte-macrophage lineages may contribute to the production of these growth factor production.TGF-β1 is more abundantly produced from the megakaryocytes than PDGF or FGF confirming TGF-β1 is the most important fibrosing growth factor in the pathogenesis of myelofibrosis in AMM.A statistically significant correlation of the growth factor and degree of myelofibrosis in AMM suggests that these fibroing growth factors produced by the megakaryocytes are main etiology of bone marrow fibrosis in AMM.

The degree of bone marrow fibrosis in chronic myelogenous leukemia is not a prognostic factor with imatinib mesylate therapy

One hundred and ten patients with Philadelphia chromosome (Ph)-positive chronic phase chronic myelogenous leukemia (CML) post-interferon-a failure treated with imatinib mesylate therapy were analyzed for the prognostic significance of marrow reticulin stain-measured fibrosis. The median time from diagnosis was 31 months. Severe reticulin (grade 3 - 4) fibrosis was observed in 67 patients (61%). Patients with severe marrow fibrosis had similar complete cytogenetic response rates with imatinib (67 vs. 58%; P = 0.45) compared with those with mild?-?moderate fibrosis. The estimated 4 year survival rates (80 vs. 88%; P = 0.27) and failure-free survival rates (69 vs. 77%; P = 0.34) were also not different. We conclude that the previously established poor prognostic significance of marrow fibrosis in CML is less relevant with imatinib therapy.

Imatinib Mesylate in Polycythemia Vera. A Heterogeneous Response Pattern but a Consistent Reduction in Phlebotomy Requirements.

Background. Imatinib targets the ATP-binding sites of the protein tyrosine kinase domains associated with Bcr-abl, platelet-derived growth factor receptors (PDGFR) and c-kit. Most recently imatinib has been to inhibit autonomous erythropoiesis in vitro in polycythemia vera (PV)(1). Several clinical studies have indicated that imatinib may reduce phlebotomy requirements (2,3), but only a few patients have been followed for longer periods on imatinib monotherapy (2,3).Aim of the study. To evaluate the safety and efficacy of long term monotherapy with imatinib in PV.Patients.Eight patients (median age 60 years, range 39–68) have been treated. Five of the patients were enrolled in a phase II treatment protocol and three patients have been treated off protocol. None of the patients in the protocol had received cytotoxic treatment whereas the three patients treated off protocol had been treated with hydroxyurea (HU) and PEG-Intron. Imatinib was given at an initial dose of 400 mg/day in all patients.Methods. The diagnosis of PV was made according to conventional criteria, including an increased red cell blood volume and a low plasma erythropoietin. All patients were negative for the Bcr-abl transcript. A complete response (CR) was defined as phlebotomy-free within the first year of treatment, lasting at least 6 mo together with a platelet count less than 600 x 109/l and absence of splenomegaly. A partial response (PR) was defined by phlebotomy-free within the first year of treatment, lasting at least 6 mo together with a platelet count more than 600 x 109/l and a palpable spleen but less than 50 % of the original size (2). A minor response (MR) was defined as a reduction in the need of phlebotomies of at least 50 % but no change in the platelet counts.Results. Four patients have been followed for 12 mo on a dose of 400 mg daily apart from short periods, when the dose had to be decreased to 100 mg/day and 300mg/day, respectively, due to temporary side effects. Responses were seen in all evaluable patients (7/7) (CR=1; PR=6). The PR's in two of the patients were obtained when HU (n=1) or PEG-Intron (n=1) were added. A definite decline in the Ht within the first month (< 0.45) and a reduction in the need of phlebotomies were recorded in all evaluable patients whereas the leucocyte and platelet counts displayed a highly heterogeneous response pattern with unchanged and even rising platelet counts in 3 patients. The one patient with a CR displayed a reduction of spleen size and a decrease in the degree of bone marrow fibrosis after being treated for 12 mo. Almost complete alleviation of severe pruritus was noticed in one patient a few weeks after starting imatinib. One patient had to discontinue treatment after 1 week due to severe musculoskeletal pain. Otherwise the side effects were moderate and often transient. One of the patients noticed no side effects at all.Conclusions. Imatinib in PV is followed by a decrease in the Ht but highly heterogeneous leucocyte-and platelet responses in some patients when using 400 mg/day.Combinational therapy with HU or PEG-Intron seems safe and effective.

Decrease of Bone Marrow Fibrosis in Hairy Cell Leukemia (HCL) after 2-CdA Therapy.

Different degree of bone marrow fibrosis is commonly described in patients with HCL. Hairy cells produce and assemble an insoluble matrix of fibronectin, which is responsible for the bone marrow fibrosis. Production of fibronectin is related to activity of the disease. The aim of our study was to evaluate the change of bone marrow fibrosis before and after 2-CdA therapy.Patients and methods: 18 patients, who were treated with 2-CdA and achieved complete remission in 6 months, were included in this analyses. Trephin bone marrow biopsy were obtained before therapy and after therapy in 12 and 24 moths. The 3μm thick section were stained with Gomori reticulin stain. Grading of reticulin fibrosis (scale of 0 to IV): grade 0 - reticulin fibers (RF) absent, grade I - scattered RF or foci of fine reticular network (RN), grade II - diffuse fine RN, grade III - diffuse fine RN and scattered thick fibers, grade IV - diffuse thick reticular fibers and presence of collagen fibers.Results: Before 2-CdA therapy: reticulin fibrosis was grade 0 in 0 p., I in 3p., II in 4p, III in 11p., IV in 0p.. Decrease of reticulin fibrosis in 12 months after 2-CdA was demonstrated in 51% of patients (grade 0 in 1, I in 8p., II in 5p., III in 4p., IV in 0p.), in 24 moths 77% of patients (grade 0 in 2, I in 10p., II in 4p., III in 2p., IV in 0p). Bone marrow fibrosis was increased by one grade in 3p. in 24 months after therapy.Conclusion: Successful 2-CdA therapy in patient with 2-CdA leads to significant reduction of bone marrow fibrosis.

Immunofluorescence and confocal laser scanning microscopy of chronic myeloproliferative disorders on archival formaldehyde-fixed bone marrow.

Spatial analysis of the histoarchitecture and photographic documentation at high resolution are the principal advantages of confocal laser scanning microscopy (CLSM) over conventional fluorescence microscopy (CFM) if combined with appropriate software. Restrictions for the use of CFM and CLSM, on the other hand, include nonspecific background fluorescence, fading of photolabile fluorochromes, and both tissue-specific and fixation-induced autofluorescence. Most of those shortcomings can now be avoided. Autofluorescence, the most limiting factor of high-resolution CLSM, was recently controlled also for paraffin sections of archival formaldehyde-fixed tissues. This allowed the present study on cytoskeletal fibers and extracellular matrix proteins in both neoplastic cells of myeloproliferative disorders and in medullary stromal cells using CLSM under proper autofluorescence control. By multiple fluorescence labeling, we found that the intracellular smooth muscle alpha-actin (SMA) fibers and the two extracellular adhesive matrix proteins tenascin and fibronectin vary in their presence in stromal and/or myeloid cells according to the degree of bone marrow fibrosis in chronic myeloproliferative disorders (CMPDs). CLSM offers further insight in our attempts to understand a complex interplay between the two cellular compartments.

Peripheral blood neutrophil morphology reflects bone marrow dysplasia in myelodysplastic syndromes.

Dysplastic features of cells in peripheral blood and bone marrow were studied in 51 patients with myelodysplastic syndromes (MDS) to evaluate the significance of the degree of neutrophil granulation (G-score) and the percentage of pelgeroid polymorphs (ppp) in the peripheral blood, as indices of dysplastic changes in the bone marrow. There was a good correlation between peripheral blood and bone marrow findings, both for G-score figures (r = 0.92, P < 0.01) and ppp (r = 0.82, P < 0.01). Significantly lower G-score figures were found among patients with an increased percentage of bone marrow blasts (P < 0.05), while high ppp correlated with the presence of ring sideroblasts, the degree of bone marrow fibrosis, and findings of complex chromosomal abnormalities. Patients with a high degree of bone marrow dysplasia had significantly lower G-score (P < 0.01) and significantly higher ppp (P < 0.05) figures, than those with less pronounced myelodysplasia. In addition, extreme hypogranulation (G-score < 150) or very high ppp (> or = 20%) was generally a sign of bi- and tri-lineage dysplasia in the bone marrow. The results thus show that quantitative estimation of peripheral blood polymorph dysplasia by G-score figures and ppp seems to reflect the total degree of bone marrow dysplasia in MDS and may serve as a complement to bone marrow evaluation when the diagnosis of MDS is difficult.

A sequential histological study of bone marrow fibrosis in idiopathic myelofibrosis

A sequential histological study of bone marrow biopsies from 36 patients with idiopathic myelofibrosis was performed to investigate the accumulation of connective tissue in the bone marrow during the course of the disease and the influence of therapy on this process. The degree of bone marrow fibrosis was graded semiquantitatively from 0 (normal) to +5 (extensive collagen fibrosis and ostemyelosclerosis). The median interval between the first and final biopsy was 25 months (range 3 to 103) in patients with chronic idiopathic myelofibrosis and 2 months (range 1 to 14) in patients with a syndrome of acute myelofibrosis. In most patients with chronic IMF the bone marrow fibrosis remained unchanged. Regression of bone marrow fibrosis in 9 patients with chronic IMF was associated with immunosuppressive/-cytotoxic treatment or splenectomy. Severe bone marrow fibrosis completely resolved during intensive chemotherapy of a patient with acute myelofibrosis. No relationship existed between spleen size and the degree of bone marrow fibrosis.

Platelet-Derived Mitogenic Activity and Bone Marrow Fibrosis in Myeloproliferative Disorders

Mitogenic activity, measured as 3H-thymidine incorporation by NIH 3T3 cells, following stimulation with platelet-rich-plasma-derived serum (PRS), platelet-poor-plasma-derived serum and platelet extract was studied in 14 patients with myeloproliferative disorders (MPD) and 7 normal subjects. Reduced mitogenic activity was found in PRS and platelet extract of patients with MPD, as compared to controls. The average levels of platelet-derived growth factor (PDGF) equivalents were as follows: 16.3 +/- 7.2 pg/10(6) platelets in controls, 6.2 +/- 2.2 pg/10(6) (p less than 0.05) platelets in patients with polycythaemia vera, 1.8 +/- 0.4 pg/10(6) (p less than 0.01) platelets in patients with idiopathic myelofibrosis and 4.0 +/- 0.8 pg/10(6) (p less than 0.05) platelets in patients with essential thrombocythaemia (Dunnett test). A reduction of intraplatelet levels of beta-thromboglobulin, although not statistically significant, was found in the same patients. No apparent relation was found between the amount of PDGF equivalents and the degree of bone marrow fibrosis.