Telomere loss in Philadelphia-negative hematopoiesis after successful treatment of chronic myeloid leukemia: evidence for premature aging of the myeloid compartment.

Telomere shortening, a well-known marker of aging and cellular stress, occurs under several conditions in the hematopoietic compartment, including aplastic anemia and following iatrogenic noxae. We decided to verify whether pathological telomere erosion also arises in restored Philadelphia-negative (Ph-negative) hematopoiesis following successful treatment of chronic myeloid leukemia (CML). Eighty-one CML patients in complete cytogenetic remission were compared to 76 age-matched healthy subjects. Myeloid cells of CML patients had shorter telomeres than controls (6521 bp vs 7233 bp, p<0.001). This difference was specific for the myeloid compartment, since it was not observed in lymphoid cells (6774 bp vs 6909 bp, p=0.620). Acquired Ph-negative cytogenetic abnormalities (p=0.010), lack of complete molecular remission (p=0.016) and age (p=0.013) were independent predictors of telomere shortening. Telomere dynamics were assessed over a median follow-up period of 22 months. We documented accelerated non-physiological ongoing telomere shortening in 17/59 CML patients (28%). Patients experiencing grade 2-4 hematological toxicity, during CML remission possessed significantly shorter telomeres compared to those lacking toxicity (p=0.005 for any toxicity, p=0.007 for anemia). CML patients suffer from significant and often ongoing telomere stress resulting in premature and selective aging of the myeloid compartment which might have long-term consequences on function and integrity of Ph-negative hematopoiesis.

An unusual febrile nonhemolytic reaction occurred after transfusion in a thalassemia major patient with asymptomatic Plasmodium falciparum infection.

BACKGROUND: Febrile nonhemolytic transfusion reactions occur in 0.12% of transfusions, usually during transfusion or within 4 to 6 hours after transfusion and are not medically dangerous. CASE REPORT: A patient with thalassemia from Togo with asymptomatic malaria in which the infection became clinically manifest only after blood transfusion, mimicking a febrile nonhemolytic transfusion reaction, is presented. Thirty-two hours after transfusion of 2 O D- red blood cell (RBC) units, the patient (phenotype A(2) D+) developed fever and multiorgan failure and was admitted to the intensive care unit. Direct and indirect antiglobulin tests were negative on posttransfusion samples. Blood cultures and infectious diseases testing were negative. No malaria parasites were found at thick blood smear microscopic examination on Days 1 and 2 and the malaria rapid diagnostic test gave inconsistent results. Plasmodium total antibodies were detected in the serum at high levels. On Day 5, routine microscopic examination of blood smear revealed the presence of parasites in a very small number of RBCs. This finding was almost simultaneous to the availability of polymerase chain reaction testing results that were positive for P. falciparum. The sequential agglutination with anti-A antiserum allowed patient's and donors' RBCs to be separated and revealed that the parasitized cells were almost exclusively those of donors (14.4% vs. 0.029%). Malaria infection in implicated donors was excluded. CONCLUSION: In this patient with thalassemia with asymptomatic malaria, the infusion of two normal RBC units provided a favorable environment for a rapid parasite replication leading to a dramatic acute malaria attack.

Oxidative stress is increased in primary and post-polycythemia vera myelofibrosis.

OBJECTIVE: To determine if increased cell turnover in chronic myeloproliferative disorders can lead to hyperhomocysteinemia as a result of folate and/or cobalamin depletion, and contribute to oxidative stress. MATERIALS AND METHODS: The clinical role of oxidative stress was investigated by measuring reactive oxygen species (ROS), total antioxidant capacity (TAC), and total homocysteine (tHcy), folate, cobalamin, and holotranscobalamin (HoloTC) levels in 51 chronic myeloproliferative disorders patients (male-to-female ratio: 1.1; median age: 64 years; range, 40-84 years), including 42 with primary myelofibrosis and 9 with post-polycythemia vera myelofibrosis. RESULTS: Myelofibrotic patients had higher tHcy (p = 0.0201) and an unbalanced oxidative status (higher ROS and lower TAC levels; p < 0.0001) than controls. Presence of diabetes or another neoplasia was associated with higher ROS levels (p < 0.05), splenomegaly, hepatomegaly, and peripheral blasts with lower HoloTC levels (p < 0.005). The most severe forms of myelofibrosis (2-3) were associated with lower TAC (p = 0.045) and HoloTC levels (p = 0.017). Patients with Janus kinase-2 mutations had lower HoloTC levels (p = 0.0059). HoloTC deficiency was more frequently associated with Janus kinase-2 homozygosity (p < 0.0003). CONCLUSIONS: Our findings suggest that the determination of HoloTC, tHcy, ROS concentrations, and TAC, can identify latent cobalamin deficiency and provide a rational basis for correcting the increased oxidation associated with disease progression.

The response to imatinib and interferon-alpha is more rapid than the response to imatinib alone: a retrospective analysis of 495 Philadelphia-positive chronic myeloid leukemia patients in early chronic phase.

Before the introduction of imatinib, interferon alpha-based regimens were the gold standard for treatment of early chronic phase chronic myeloid leukemia patients. The combination of IFN-alpha with imatinib is currently being investigated in at least two large clinical trials, the German CML Study IV and the French SPIRIT trial. We reviewed the cytogenetic and molecular responses of 76 early chronic phase chronic myeloid leukemia patients who were treated with imatinib and interferon-alpha and of 419 early chronic phase chronic myeloid leukemia patients treated with imatinib alone front-line. The complete cytogenetic response rate was higher in the IM+IFN-alpha group than in the imatinib group at six months (60% vs. 42%; P=0.003), but not at 48 months (88% vs. 88%). The durability of the complete cytogenetic response was similar in the two groups with 94% and 91% of complete cytogenetic responders in continuous complete cytogenetic response at 48 months (P=0.56). The major molecular response rate was higher in the IM+IFN-alpha group at six months (58% vs. 34%; P=0.0001) and 12 months (67% vs. 47%; P=0.001) but not later on (65% vs. 57% at 48 months; P=0.25). Overall and progression free survival were comparable in the two groups; a significant trend to a better event free survival was observed in patients treated with PegIFNalpha (91% vs. 78%; P=0.02). These data suggest that the response to the combination treatment is more rapid. It is not yet known how much a rapid reduction will influence the longer-term overall and progression free survival, and the cure rate.

Outcome of 122 pregnancies in essential thrombocythemia patients: A report from the Italian registry.

Pregnancy is a high-risk event in women with essential thrombocythemia (ET). This observational study evaluated pregnancy outcome in ET patients focusing on the potential impact of aspirin (ASA) or interferon alpha (IFN) treatment during pregnancy. We retrospectively analyzed 122 pregnancies in 92 women consecutively observed in the last 10 years in 17 centers of the Italian thrombocythemia registry (RIT). The live birth rate was 75.4% (92/122 pregnancies). The risk of spontaneous abortion was 2.5-fold higher than in the control population (P < 0.01). ASA did not affect the live birth rate (71/93, 76.3% vs. 21/29, 72.4%, P = 0.67). However, IFN treatment during pregnancy was associated with a better outcome than was management without IFN (live births 19/20, 95% vs. 73/102, 71.6%, P = 0.025), and this finding was supported by multivariate analysis (OR: 0.10; 95% CI: 0.013-0.846, P = 0.034). The JAK2 V617F mutation was associated with a poorer outcome (fetal losses JAK2 V617F positive 9/25, 36% vs. wild type 2/24, 8.3%, P = 0.037), and this association was still significant after multivariate analysis (OR: 6.19; 95% CI: 1.17-32.61; P = 0.038). No outcome concordance between first and second pregnancies was found (P = 0.30). Maternal complications occurred in 8% of cases. In this retrospective study, in consecutively observed pregnant ET patients, IFN treatment was associated with a higher live birth rate, while ASA treatment was not. In addition, the JAK2 V617F mutation was confirmed to be an adverse prognostic factor.

In vitro anti-leukaemia activity of sphingosine kinase inhibitor.

Compelling evidence indicates the role of sphingosine kinase 1 (SPHK1) deregulation in the processes of carcinogenesis and acquisition of drug resistance, providing the rationale for an effective anti-cancer therapy. However, no highly selective inhibitors of SPHK1 are available for in vitro and in vivo studies, except for the newly discovered 'SK inhibitor' (SKI). The present study showed that, in a panel of myeloid leukaemia cell lines, basal level of SPHK1 correlated with the degree of kinase inhibition by SKI. Exposure to SKI caused variable anti-proliferative, cytotoxic effects in all cell lines. In particular, SKI induced an early, significant inhibition of SPHK1 activity, impaired cell cycle progression and triggered apoptosis in K562 cells. Moreover, SKI acted synergistically with imatinib mesylate (IM) to inhibit cell growth and survival. Finally, the inhibitor affected the clonogenic potential and viability of primary cells from chronic myeloid leukaemia (CML) patients, including one harbouring the IM-insensitive Abl kinase domain mutation T315I. Due to the fact that the phenomenon of resistance to IM remains a major issue in the treatment of patients with CML, the identification of alternative targets and new drugs may be of clinical relevance.

Second malignancies in essential thrombocythemia (ET): a retrospective analysis of 331 patients with long-term follow-up from a single institution.

Essential thrombocythemia (ET) is a myeloproliferative disorder characterized by an indolent clinical course, with a median survival exceeding 20 years. A minority of patients undergo thrombohemorrhagic complications, which might be prevented by cytoreductive treatment in high risk categories. Alkylating agents (ALK) have been demonstrated to increase the risk of acute leukemia and myelodysplastic syndromes in patients with myeloproliferative disorders, whereas the potential oncogenicity of hydroxyurea (HU) remains a matter of debate. In this study, we retrospectively investigated long-term development of hematological and non-hematological second malignancies in 331 patients with ET, analyzing possible associations with chemotherapy treatments. Median follow-up was 108 months. Of the 194 patients who were treated with chemotherapy, 116 (60%) received only HU, 38 (19.5%) only ALK (busulfan or melphalan) and 40 (20.5%) ALK followed by HU. After a median time of 87 months from the diagnosis of ET, 43 patients developed a second malignancy, hematological in 15 and non-hematological in 28, for an overall cumulative incidence of 13%. According to the type of treatment, second malignancies were documented in 11.2% of patients treated with only HU, in 26.3% of patients who received only ALK, and in 25% of those treated with ALK followed by HU. Ten cases (7.3%) were recorded among the 137 patients who did not receive any treatment. Our analysis revealed a significant association between treatment with alkylating agents and an increased risk of developing second hematological malignancies, whereas no such association was detected with regard to treatment with hydroxyurea single agent in our ET population. In addition, different treatment strategies did not affect the risk of developing second solid cancers.

The significance of bone marrow biopsy and JAK2V617F mutation in the differential diagnosis between the "early" prepolycythemic phase of polycythemia vera and essential thrombocythemia.

It has been suggested that polycythemia vera (PV) could be preceded by an "early" phase of the disease (e-PV), in which the increase in the red cell parameters is lower than required for a PV diagnosis. In this study, we compared the clinicopathologic and molecular features of 17 patients with e-PV with those of 14 patients with essential thrombocythemia (ET) and 19 with PV. The results for e-PV were more similar to those for PV than for ET. In fact, patients with e-PV were characterized by an increase in the red cell parameters, splenomegaly (P<.05), and hepatomegaly (P=.038), together with hypercellular bone marrow due to increased erythropoiesis and granulopoiesis, associated with megakaryocytic hyperplasia, with pleomorphic aggregates (P<.001). The frequency of the JAK2V617F mutation was similar in e-PV (16 cases tested [100%]) and PV (18/19 [95%]) but was significantly lower (7/13 [54%]) in ET (P=.0007). We propose a diagnostic algorithm helpful to distinguish ET from the early prepolycythemic phase of PV.

Prognostic implications of the European consensus for grading of bone marrow fibrosis in chronic idiopathic myelofibrosis.

Various clinical prognostic scoring systems (PSSs) have been suggested as means of selecting high-risk chronic idiopathic myelofibrosis (CIMF) patients at diagnosis. The WHO has recently proposed strict diagnostic criteria for CIMF, and the European consensus for bone marrow fibrosis (BMF) grading recommends 4 classes. It has been suggested that BMF grading may play a prognostic role in CIMF, but it has never been compared with the other PSSs in the same patients. We tested a prognostic model for overall survival (OS) based on the WHO criteria and BMF grading in 113 consecutive patients with chronic myeloproliferative disorders (98 with CIMF and 15 with postpolycythemic myelofibrosis), and compared the findings with those of PSSs. The results showed that our model is significantly associated with different OSs and, unlike the other PSSs, clearly discriminates the OS of intermediate- and high-risk patients.

VEGF expression correlates with microvessel density in Philadelphia chromosome-negative chronic myeloproliferative disorders.

We examined microvessel density (MVD) and immunohistochemical expression of vascular endothelial growth factor (VEGF) in the bone marrow biopsy specimens of 98 patients with Philadelphia chromosome-negative (Ph-) chronic myeloproliferative disorders (CMPDs). There were significantly more MVD "hot spots" in chronic idiopathic myelofibrosis (CIMF; mean +/- SD, 25.6 +/- 6.3) and polycythemia vera (PV; 20.7 +/- 10.2) cases than in essential thrombocythemia (ET) cases (10.1 +/- 4.5) and normal control (NC) samples (7.5 +/- 3.6) (P < .05). Similar results were found using a semiquantitative method (P < .0001). A calculated VEGF index (VEGF(i)) was higher in CIMF (0.29 +/- 0.15) and PV (0.28 +/- 0.20) cases than in ET (0.12 +/- 0.05) and NC (0.08 +/- 0.04) cases (P < .0001). MVD and VEGF(i) were higher in the myelofibrotic phases of CIMF and PV. There was a direct correlation between VEGF(i) and MVD when considering the Ph- CMPDs together (r = 0.67; P < .001) and when considering PV (r = 0.79; P < .001) and CIMF (r = 0.40; P = .013) as individual entities. Our data could provide a rationale for directly targeting VEGF or endothelial cells in CIMF and PV.

Analysis of risk factors predicting thrombotic and/or haemorrhagic complications in 306 patients with essential thrombocythemia.

Thrombotic and haemorrhagic complications are the main causes of morbidity in Essential Thrombocythemia (ET). We investigated the clinical and laboratory characteristics associated with the occurrence of these events with the aim of identifying subgroups of patients who might benefit from anti-aggregant and/or cytoreductive therapy. The study involved 306 consecutive ET patients (median age 58 years and median follow-up 96 months); the investigated variables were age, gender, platelet count, previous history of thrombotic or haemorrhagic events, disease duration and cardiovascular risk factors. Forty-six patients (15%) experienced thrombotic complications during the follow-up: 26/64 patients with a previous history of thrombosis (40.6%) and 20/242 patients without (8.3%; p < 0.0001). Thirty-one patients (10%) experienced major haemorrhagic complications, mainly gastrointestinal tract bleeding: 3 with and 28 without a history of haemorrhagic events (p = 0.052). When the patients with a negative history of thrombosis were stratified on the basis of the number of cardiovascular risk factors (none vs. one vs. more than one), there was a significant correlation with the occurrence of thrombotic events (p < 0.05). ET patients with a positive history of thrombosis are at high risk of thrombotic complications, and should receive cytoreductive and anti-aggregant treatment. Asymptomatic patients with a negative thrombotic history and no cardiovascular risk factors are at low risk, and should not be treated. Patients with a negative thrombotic history and one or more cardiovascular risk factors are at intermediate risk, and should be treated with anti-aggregant and/or cytoreductive therapy. The need for treatment should be periodically re-evaluated. Age and platelet count, generally accepted as very important risk factors for thrombosis, did not seem in our series associated with an increased risk for thrombosis.

Conjunctival hemorrhagic events associated with imatinib mesylate.

Imatinib mesylate (IM) is used in the targeted therapy of chronic myelogenous leukemia and gastrointestinal stromal tumors. It is well tolerated and leads to no higher incidence of hemorrhagic events than other therapies. Of 87 patients we treated with IM for a minimum of 3 months, 10 patients (11%) developed unilateral or bilateral conjunctival hemorrhage (CH). No other hemorrhagic events were observed during follow-up, except for CH recurrence in 6 cases (7%). Because there was no other obvious reason for such a high incidence of CH, we hypothesize drug hypersensitivity or ocular irritation induced by IM treatment.

Contribution of ABL kinase domain mutations to imatinib resistance in different subsets of Philadelphia-positive patients: by the GIMEMA Working Party on Chronic Myeloid Leukemia.

PURPOSE: ABL kinase domain mutations have been implicated in the resistance to the BCR-ABL inhibitor imatinib mesylate of Philadelphia-positive (Ph+) leukemia patients. EXPERIMENTAL DESIGN: Using denaturing high-performance liquid chromatography and sequencing, we screened for ABL kinase domain mutations in 370 Ph+ patients with evidence of hematologic or cytogenetic resistance to imatinib. RESULTS: Mutations were found in 127 of 297 (43%) evaluable patients. Mutations were found in 27% of chronic-phase patients (14% treated with imatinib frontline; 31% treated with imatinib post-IFN failure), 52% of accelerated-phase patients, 75% of myeloid blast crisis patients, and 83% of lymphoid blast crisis/Ph+ acute lymphoblastic leukemia (ALL) patients. Mutations were associated in 30% of patients with primary resistance (44% hematologic and 28% cytogenetic) and in 57% of patients with acquired resistance (23% patients who lost cytogenetic response; 55% patients who lost hematologic response; and 87% patients who progressed to accelerated phase/blast crisis). P-loop and T315I mutations were particularly frequent in advanced-phase chronic myeloid leukemia and Ph+ ALL patients, and often accompanied progression from chronic phase to accelerated phase/blast crisis. CONCLUSIONS: We conclude that (a) amino acid substitutions at seven residues (M244V, G250E, Y253F/H, E255K/V, T315I, M351T, and F359V) account for 85% of all resistance-associated mutations; (b) the search for mutations is important both in case of imatinib failure and in case of loss of response at the hematologic or cytogenetic level; (c) advanced-phase chronic myeloid leukemia and Ph+ ALL patients have a higher likelihood of developing imatinib-resistant mutations; and (d) the presence of either P-loop or T315I mutations in imatinib-treated patients should warn the clinician to reconsider the therapeutic strategy.

Essential thrombocythemia or chronic idiopathic myelofibrosis? A single-center study based on hematopoietic bone marrow histology.

We reviewed a large series of patients with essential thrombocythemia diagnosed on the basis of the Polycythemia Vera Study Group criteria, and reclassified them by evaluating their major morphologic features and clinical course using the World Health Organization classification. The morphologic review of the bone marrow biopsies of 116 patients (44 males and 72 females; aged 19 - 83 years, median 55 years; median follow-up 121 months) led to 22 cases (19%) being classified as essential thrombocythemia (ET), 24 (21%) as chronic idiopathic myelofibrosis (CIMF)-0, 44 (37%) as CIMF-1, 13 (12%) as CIMF-2, 9 (8%) as latent phase polycythemia vera, and four (3%) as chronic myeloproliferative disorder, unclassifiable. There was a significant difference in the median age of the ET and fibrotic CIMF patients (54.7 +/- 13.55 vs. 59.13 +/- 15.05 years; P = 0.03). Histologic analysis showed that the simultaneous presence of loose clusters of large/giant megakaryocytes and nuclear hyperlobulation was significantly different between the ET and the prefibrotic CIMF (P<0.01) and fibrotic CIMF patients (P<0.01), and that the association of dense clusters of megakaryocytes with maturation defects and bulbous nuclei also distinguished the prefibrotic CIMF (P<0.05) and fibrotic CIMF patients (P<0.001) from those with ET. The association of cellularity, granulocytic proliferation and reticulin fibers was helpful in distinguishing prefibrotic from fibrotic CIMF (P<0.001).

Acute megakaryocytic leukemia in essential thrombocythemia: an unusual evolution?

Essential thrombocythemia (ET) is a chronic myeloproliferative disorder that can rarely undergo leukemic transformation either in treated (3-7%) or untreated patients (1%). Evolution to myeloblastic or myelomonoblastic acute leukemia is commonly described in the literature, whereas lymphatic and megakaryocytic forms are considered unusual. Here, we report three cases of acute megakaryocytic leukemia (LMA-M7) among 11 acute leukemic transformations observed in our series of 321 ET patients. LMA-M7 was diagnosed employing immunophenotyping according to FAB criteria. These recurrences of LMA M7 suggest that this kind of evolution cannot be considered rare or casual in ET.