Antioxidant status and superoxide anion radical generation in acute myeloid leukemia

OBJECTIVES

This study was undertaken to investigate if there is a disparity in the antioxidant status and the ability of superoxide anion (O(2)(-)) generation in the patients with acute myeloid leukemia (AML).

DESIGN AND METHODS

The peripheral blood samples from thirty AML patients and thirty-six healthy subjects were collected and leukocytes, erythrocytes and plasma were separated for use in various parameter measurements.

RESULTS

The generation of O(2)(-), as reflected by lucigenin-based CL (LBCL), by the leukocytes of patients with AML was found to be significantly elevated either in resting or stimuli-elicited condition as compared with that of healthy controls (p<0.05). Coincidentally, these data were matched up with the suppressed SOD activities, notably in Cu/Zn SOD isoform found in AML patients (p<0.05). Conversely, SOD and GPx activities in erythrocytes of patients with AML were shown to be significantly higher than their normal counterparts (p<0.05).

CONCLUSIONS

These data suggest that altered expression of antioxidant enzymes and higher capability of O(2)(-) generation by leukocytes seem to be a distinct feature of AML.

Hyperglycemia in patients with acute myeloid leukemia is associated with increased hospital mortality

BACKGROUND

Hyperglycemia is often observed in medically ill patients. Previous studies have shown that patients with hyperglycemia during induction therapy for acute lymphoblastic leukemia develop more infections and have shorter disease-free survival. The authors hypothesized that hyperglycemia may be associated with adverse outcomes in patients with acute myeloid leukemia (AML) and sought to determine whether this association exists in this population.

METHODS

The authors performed a retrospective cohort study to examine the relation between hyperglycemia and hospital mortality in patients with the diagnosis of AML. Two hundred eighty-three adult patients were treated over a 3-year period. All hospitalizations were reviewed during the study period, and glucose exposure and outcomes were quantified.

RESULTS

Hyperglycemia during a patient's hospitalization was associated with increased hospital mortality (OR, 1.38; 95% CI, 1.23-1.55; P < .001) after adjusting for covariates, including disease state, treatment type, and response. The rise in mortality was evident at even mild levels (110-150 mg/dL) of glucose elevation. Although the odds of developing severe sepsis (OR, 1.24; 95% CI, 1.13.-1.38; P < .001) or severe sepsis with respiratory failure (OR, 2.04; 95% CI, 1.44-2.91; P < .001) were increased with hyperglycemia, sepsis did not appear to be the main factor responsible for the negative impact of hyperglycemia on hospital mortality.

CONCLUSIONS

This study demonstrated an association between hospital mortality and even modest levels of hyperglycemia in AML patients. Prospective studies are needed to confirm this association and to discern causal pathways that mediate this effect.

Current status of growth factors in the treatment of acute myeloid and lymphoblastic leukemia

The safety of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with acute leukemia has been well established in numerous clinical trials. The primary aim of these studies was to determine whether CSFs, when used as adjuncts to intensive chemotherapy, reduced the duration of neutropenia, prevented febrile neutropenia, infections, and hospitalization rates, and improved response and overall outcome in patients with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). Despite considerable efforts in divers clinical settings, the potential advantages of hematopoietic growth factors in the management of these leukemias remain inconclusive. In general, individual published trials have shown declines in the incidence and/or duration of neutropenia but have not consistently demonstrated a reduction in the overall frequency of infectious complications or the duration of hospitalization. Most protocols also have failed to show a benefit in terms of disease-free or overall survival. Nevertheless, improvements in "soft" clinical end points, such as incidence of severe infections, may be clinically important and contribute, even if only incrementally, to the patient's quality of life. Selection of those patients likely to benefit from growth factors in a specific clinical setting is a worthwhile endeavour.

Circulating angiopoietin-2 is a strong prognostic factor in acute myeloid leukemia

Angiogenesis plays an important role in solid tumors and hematologic malignancies. The angiopoietins act as essential regulators in this process. We investigated the impact of circulating angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and soluble Tie2 (sTie2) on overall survival in patients with acute myeloid leukemia (AML). Ang-1, Ang-2 and sTie2 were measured in plasma samples from 68 AML patients and 11 controls using enzyme-linked immunosorbent assay. Circulating levels of Ang-2 and sTie2 (median (range): 1098.0 (361.4-4147.6) pg/ml and 3.40 (1.21-10.00) ng/ml, respectively) were significantly elevated in AML patients as compared to controls (307.9 (199.7-1225.0) pg/ml and 2.88 (1.71-3.29) ng/ml; P<0.001 and P=0.014). In a univariate Cox proportional hazards model, higher levels of Ang-2 and sTie2 were predictive of poor survival. In multivariate analyses, Ang-2 and cytogenetics proved to be independent prognostic factors, with a relative risk of 4.07 (95% confidence interval (CI) 1.88-8.81) and 2.70 (95% CI 1.25-5.81), respectively. The 3-year survival rate for AML patients with Ang-2 levels>/=1495.6 pg/ml was only 14.7% compared to 64.7% for those with Ang-2 levels<1495.6 pg/ml. These data provide evidence that circulating Ang-2 represents an independent prognostic factor in AML and may be used as a prognostic tool in the risk-adapted management of AML.

Neoplastic circulating endothelial-like cells in patients with acute myeloid leukaemia

Accumulating evidence suggests that angiogenesis may play a key role in the pathogenesis of leukaemic disorders. Several studies have shown that bone marrow-derived endothelial cells (EC) may contribute to tumour angiogenesis and that in the peripheral blood of cancer patients there is an increased amount of circulating ECs (CECs) that may participate to new vessel formation. In this report, we showed that, in seven acute myeloid leukaemia (AML) patients with known cytogenetic abnormalities, CEC levels were significantly increased in comparison with controls and that a significant proportion of these CECs carried the same chromosomal aberration as blast cells (20-78%, mean value 42.1% of CECs). Most of CECs (mean value 74.4%) displayed immunophenotypic features of endothelial progenitor cells as they expressed CD133, a marker gradually lost during EC differentiation and absent on mature EC. These findings suggest a possible direct contribution of AML-related CECs to tumour vasculogenesis and possibly to the spreading and progression of the disease.

Monitoring of minimal residual disease in adult acute myeloid leukemia using peripheral blood as an alternative source to bone marrow

BACKGROUND AND OBJECTIVES

To date, bone marrow (BM) is the most common source of cells to use in order to assess minimal residual disease (MRD) in acute myeloid leukemia (AML). In the present study, we investigated whether peripheral blood (PB) could be an alternative source of cells for monitoring MRD in AML.

DESIGN AND METHODS

Fifty patients with AML were monitored for MRD after the achievement of complete remission. Using multiparametric flow cytometry we compared the levels of MRD in 50 and 48 pairs of BM and PB after induction and consolidation, respectively.

RESULTS

After induction and consolidation therapy, the findings in BM and PB were significantly concordant (r=0.86 and 0.82, respectively, p<0.001 for both comparisons). The cut-off value of residual leukemic cells in PB which correlated with outcome was 1.5x10 (-4). Thirty-three of 43 (77%) patients with >1.5x10 (-4)residual leukemic cells in PB after induction had a relapse, whereas the seven patients with lower levels did not (p=0.0002). After consolidation, 38 patients had a level of MRD >1.5x10 (-4)and 31 (82%) had a relapse; nine out of the remaining ten patients, whose levels of MRD were below 1.5x10 (-4), are still relapse-free (p=0.00006). In multivariate analysis, PB MRD status at the end of consolidation was found to have a significant effect on relapse-free survival (p=0.036).

INTERPRETATION AND CONCLUSIONS

These preliminary results indicate that: (i) PB evaluation can integrate BM assessment for MRD detection in patients with AML; (ii) PB MRD status at the end of consolidation therapy may provide useful prognostic information.

A Case Report of Therapeutic Leukapheresis in an Adult With Chronic Myelogenous Leukemia Presenting With Hyperleukocytosis and Leukostasis

Hyperleukocytosis (>100 x 10(9)/L) is an uncommon presentation of chronic leukemias. It can present with a variety of symptoms secondary to leukostasis, a syndrome caused by the sludging of circulating leukemic blasts in the microvasculature. The management includes hydration, cytoreduction, prevention of tumor lysis and, rarely, leukapheresis in cases complicated by leukostasis and hyperviscosity syndrome. We present a case of severe leukocytosis complicated by leukostasis in which leukapheresis was utilized to bring about a rapid reversal of microvascular sludging.

Transcriptional Profiling of Hematologic Malignancies with a Low-Density DNA Microarray

Background: High-density microarrays are powerful tools for expression analysis of thousands of genes simultaneously; however, experience with low-density microarrays in gene expression studies has been limited.

Methods: We developed an optimized procedure for gene expression analysis based on a microarray containing 538 oligonucleotides and used this procedure to analyze neoplastic cell lines and whole-blood samples from healthy individuals and patients with different hematologic neoplasias. Hierarchical clustering and the Welch t-test with adjusted P values were used for data analysis.

Results: This procedure detects 0.2 fmol of mRNA and generates a linear response of 2 orders of magnitude, with CV values of &lt;20% for hybridization and label replicates. We found statistically significant differences between Jurkat and U937 cell lines, between blood samples from 15 healthy donors and 59 chronic lymphocytic leukemia (CLL) samples, and between 6 acute myeloid leukemia patients and 4 myelodysplastic syndrome patients. A classification system constructed from the expression data predicted healthy or CLL status from a whole-blood sample with a 97% success rate.

Conclusion: Transcriptional profiling of whole-blood samples was carried out without any cellular or sample manipulation before RNA extraction. This gene expression analysis procedure uncovered statistically significant differences associated with different hematologic neoplasias and made possible the construction of a classification system that predicts the healthy or CLL status from a whole-blood sample.

Novel methodology for assessment of prophylactic platelet transfusion therapy by measuring increased thrombus formation and thrombin generation

Currently, patients developing severe thrombocytopenia during chemotherapy treatment are prophylactically transfused with platelets. We developed two platelet function tests to report the improved haemostasis in the transfused patients, which were capable of detecting aberrant responsiveness of the platelets after transfusion. First, in a whole-blood flow test, platelet adhesion and thrombus formation were determined under high-shear flow conditions. Second, the procoagulant function of platelets was assayed in platelet-rich plasma by measurement of thrombin generation. Experimental conditions were established, where flow-induced adhesion and thrombin generation test parameters increased semi-linearly with the platelet concentration, and informed on the activation properties of platelets. The transfusion effects were evaluated for 38 thrombocytopenic patients, who were transfused with platelets stored in plasma or in synthetic medium (platelet additive solution II). In most but not all patients, transfusion resulted in increased adhesion and thrombus formation, as well as in improved platelet-dependent coagulation. Taken together, the increase in platelet count after transfusion explained 57% of the overall improvement in platelet function. In acute graft-versus-host disease, thrombus formation was normal, while platelet-dependent coagulation was higher than expected. We conclude that assessment of flow-induced adhesion and thrombin generation in acquired thrombocytopenia adequately determines the improved haemostatic activity by transfused platelets.

Levels of soluble HLA-I and beta2M in patients with acute myeloid leukemia and advanced myelodysplastic syndrome: association with clinical behavior and outcome of induction therapy

beta-2 Microglobulin (beta2M), a subunit of human leukocyte antigen-class I (HLA-I), is well established as a marker of prognosis in various solid tumors and hematologic malignancies. The prognostic role of intact free-circulating HLA-I (sHLA-I) is less well understood. We compared the clinical relevance of plasma levels of sHLA-I and beta2M in patients with acute myeloid leukemia (AML; n=209) or advanced myelodysplastic syndrome (MDS; n=98). sHLA-1 and beta2M levels were significantly higher in AML and MDS patients than in control subjects, but did not differ significantly between the two disease groups. In AML patients, multivariate analysis showed both sHLA-1 and beta2-M to be highly predictive of complete remission (CR), survival and duration of complete response (CRD). In MDS, the predictive value of the two markers differed substantially from one another: beta2M was associated with survival, CR and CRD, whereas sHLA-I was not. These findings not only establish the role of sHLA-I as a tumor marker in AML but also support that MDS is clinically and biologically distinct from AML. sHLA-I has been reported to be an immunomodulator inhibiting the cytotoxic effects of T-lymphocytes, which may offset its predictive value for disease aggressiveness in patients with MDS.

Increased monocyte chemoattractant protein 1 (MCP-1/CCL-2) serum level in acute myeloid leukemia

Acute myeloid leukaemia (AML) is an aggressive malignancy with accumulation of blasts in bone marrow. Myeloblasts can entry into peripheral blood stream and secondary localize in extramedullary sites. The regulation of this process has not been clearly explained so far, but interactions between some chemokines and their specific receptors could be one of the mechanisms responsible for such kind of migration. Monocyte chemoattractant protein 1 (MCP-1/CCL2) is the chemokine which could be involved in this process. The aim of the study was to evaluate plasma level of CCL2 in patients with AML. Plasma samples from 65 adult patients with AML taken before chemotherapy and in complete remission were measured by enzyme linked immunoassay to evaluate CCL2 levels. Control group consisted of 15 healthy subjects. In AML patients mean baseline CCL2 level (+/- SEM standard error of measurement) was significantly higher than in normal control: 365,26 +/- 5,62 pg/ml vs 265,56 +/- 5,48 pg/ml respectively (p<0.01). We demonstrate increased mean CCL2 plasma level in untreated patients with AML. Significantly lower plasma level of CCL2 was observed in patients with M4 and M5 AML subtypes according to FAB classification. In AML group chemotherapy did not reduce CCL2 plasma level.

Prognostic relevance of circulating matrix metalloproteinase-2 in acute myeloid leukaemia patients

Matrix metalloproteinases (MMPs) were postulated to have important implication in progression and invasiveness of many malignant disorders. On the other hand the biological role of MMP-2 in acute myeloid leukaemia (AML) is not fully clear. Serum samples from 37 adult patients with AML had been taken before chemotherapy was administered. In addition 20 out of the 37 patients were analysed again after achieving complete remission (CR). Ten samples from healthy volunteers were evaluated as the control. Total MMP-2 levels were measured using ELISA Kit obtained from R&D system. MMP-2 serum levels were significantly lower in pretreatment AML patients than that in the normal controls (p = 0.000) and in CR (p = 0.007). No significant correlations were detected between pretreatment sMMP-2 levels and FAB subtypes, peripheral blood blast cell counts, peripheral blood WBCs, bone marrow blast cell counts or blast cell distribution ratio. The prognostic value of MMP-2 was evaluated by dividing AML patients into high and low MMP-2 groups using the pretreatment median MMP-2 level of the AML group as the cut-off. The authors found that patients in the high group survived for a significantly shorter time than those patients in the lower MMP-2 group. High pretreatment levels of sMMP-2 among AML patients were associated with poor survival. Prospective studies are recommended to establish the clinical value of longitudinal sMMP-2 measurement.

Growth inhibition and induction of apoptosis in acute myeloid leukemia cells by new indolinone derivatives targeting fibroblast growth factor, platelet-derived growth factor, and vascular endothelial growth factor receptors

In acute myeloid leukemia (AML), receptor tyrosine kinase ligands promote growth and survival and contribute to AML-associated marrow neoangiogenesis. We have tested simultaneous inhibition of vascular endothelial growth factor, fibroblast growth factor, and platelet-derived growth factor receptor signaling by novel indolinone derivatives using 14 myeloid, including 11 human leukemic, cell lines. Compounds inhibited colony formation of all cell lines in a dose-dependent fashion. Inhibitory concentrations for 50% of the colony formation/survival (IC50) for BIBF1000 were <100 nmol/L for 3 of 11, <or=500 nmol/L for 6 of 11, and <1,000 nmol/L for 10 of 11 leukemic cell lines, with one cell line being resistant in the dose range <1,000 nmol/L. BIBF1120 was less effective with 4 of 11 leukemic cell lines being resistant within the dose range <1,000 nmol/L. Testing of myeloid 32D cells transfected with empty vector, wild-type Flt3, or Flt3 carrying an internal tandem duplication mutation revealed higher resistance for the internal tandem duplication mutant. These effects of the compounds were associated with inhibition of tyrosine phosphorylation and the mitogen-activated protein kinase pathway. Furthermore, both compounds induced apoptosis in the sensitive cell lines. In Mono-Mac1 cells, the compounds had a direct proapoptotic effect that was increasing the proapoptotic effect of 1-beta-D-arabinofuranosylcytosine. The data provide a rationale for clinical evaluation of these tyrosine kinase inhibitors in AML.

Chromosome 5q deletion and epigenetic suppression of the gene encoding α-catenin (CTNNA1) in myeloid cell transformation

Interstitial loss of all or part of the long arm of chromosome 5, or del(5q), is a frequent clonal chromosomal abnormality in human myelodysplastic syndrome (MDS, a preleukemic disorder) and acute myeloid leukemia (AML), and is thought to contribute to the pathogenesis of these diseases by deleting one or more tumor-suppressor genes. Although a major commonly deleted region (CDR) has been delineated on chromosome band 5q31.1 (refs. 3-7), attempts to identify tumor suppressors within this band have been unsuccessful. We focused our analysis of gene expression on RNA from primitive leukemia-initiating cells, which harbor 5q deletions, and analyzed 12 genes within the CDR that are expressed by normal hematopoietic stem cells. Here we show that the gene encoding alpha-catenin (CTNNA1) is expressed at a much lower level in leukemia-initiating stem cells from individuals with AML or MDS with a 5q deletion than in individuals with MDS or AML lacking a 5q deletion or in normal hematopoietic stem cells. Analysis of HL-60 cells, a myeloid leukemia line with deletion of the 5q31 region, showed that the CTNNA1 promoter of the retained allele is suppressed by both methylation and histone deacetylation. Restoration of CTNNA1 expression in HL-60 cells resulted in reduced proliferation and apoptotic cell death. Thus, loss of expression of the alpha-catenin tumor suppressor in hematopoietic stem cells may provide a growth advantage that contributes to human MDS or AML with del(5q).

Distribution of ABO blood groups in childhood acute leukemia

The distribution of ABO blood groups was determined in a multicenter study of 682 pediatric patients with acute lymphoblastic leukemia (ALL) and 224 patients with acute myeloid leukemia (AML) up to 12 years old. The overall distribution of blood groups was significantly different in both ALL and AML groups from the control group (p < .001). In the ALL group there were 56.5% (95% CI: 45.8-67.1) more patients with O blood group, 35.8% (95% CI: 27.0-44.5) fewer patients with A blood group, and 26.9% (95% CI: 12.7-39.2) fewer patients with B blood group. In the AML group, there were 28.8% (95% CI: 10.8-46.9) more patients with A blood group. The results indicate that alteration in ABO antigens might be associated with an increased risk of ALL.

Inhibitory effect of curcumin onMDR1 gene expression in patient leukemic cells

When patients with cancers are treated with chemotherapeutic agents a long time, some of the cancer cells develop the multidrug resistance (MDR) phenotype. MDR cancer cells are characterized by the overexpression of multidrug resistance1(MDR1) gene which encodes P-glycoprotein (Pgp), a surface protein of tumor cells that functions to produce an excessive efflux and thereby an insufficient intracellular concentration of chemotherapeutic agents. A variety of studies have sought potent MDR modulators to decrease MDR1 gene expression in cancer cells. Our previous study has shown that curcumin exhibits characteristics of a MDR modulator in KB-V1 multidrug-resistant cells. The aim of this study was to further investigate the effect of curcumin on MDR1 gene expression in patient leukemic cells. The leukemic cells were collected from 78 childhood leukemia patients admitted at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, in the period from July 2003 to February 2005. There were 61 cases of acute lymphoblastic leukemia (ALL), 14 cases of acute myeloblastic leukemia (AML), and 3 cases of chronic myelocytic leukemia (CML). There were 47 males and 31 females ranging from 1 to 15 years old. Bone marrows were collected. The leukemic cells were separated and cultured in the presence or absence of 10 microM curcumin for 48 hours. MDR1 mRNA levels were determined by RT-PCR. It was found that curcumin reduced MDR1 gene expression in the cells from 33 patients (42%). Curcumin affected the MDR1 gene expression in 5 of 11 relapsed cases (45%), 10 of 26 cases of drug maintenance (38%), 7 of 18 cases of completed treatment (39%), and 11 of 23 cases of new patients (48%). The expression levels of MDR1 gene in leukemic patient cells as compared to that of KB-V1 cells were classified as low level (1-20%) in 5 of 20 cases (25%), medium level (21-60%) in 14 of 32 cases (44%), and high level (61-100%) in 14 of 20 cases (70%). In summary, curcumin decreased MDR1 mRNA level in patient leukemic cells, especially in high level of MDR1 gene groups. Thus, curcumin treatment may provide a lead for clinical treatment of leukemia patients in the future.

The clinical spectrum of adult acute myeloid leukaemia associated with core binding factor translocations

To better understand the spectrum of adult acute myeloid leukaemia (AML) associated with core binding factor (CBF) translocations, 370 patients with newly diagnosed CBF-associated AML were analysed. Patients' age ranged from 16-83 years (median 39 years) with a slight male predominance (55%); 53% had inv(16); 47% had t(8;21). Patients with t(8;21) tended to be younger (P = 0.056), have lower peripheral blood white cell counts (P < 0.0001) and were more likely to have additional cytogenetic abnormalities (P < 0.0001). Loss of sex chromosome, del(9q) and complex abnormalities were more common among patients with t(8;21), while +22 and +21 were more common with inv(16). Overall, 87% [95% confidence interval (CI) 83-90%] of patients achieved complete response (CR) with no difference between t(8;21) and inv(16); however, the CR rate was lower in older patients due to increased resistant disease and early deaths. Ten-year overall survival (OS) was 44% (95% CI 39-50%) and, in multivariate analysis, was shorter with increasing age (P < 0.0001), increased peripheral blast percentage (P = 0.0006), in patients with complex cytogenetic abnormalities in addition to the CBF translocation (P = 0.021), and in patients with t(8;21) (P = 0.025). OS was superior in patients who received regimens with high-dose cytarabine, a combination of fludarabine and intermediate-dose cytarabine, or haematopoietic cell transplantation.

[Haematological characteristics, FAB and WHO classification of 153 cases of myeloid acute leukaemia in Tunisia]

A complete blood analysis with a careful morphologic examination of peripheral blood and bone morrow smears completed by cytochemical reaction will help to classify the most acute myeloid leukaemia (AML). Actually, the study of other cytogenetis and immunophenotypic markers are now necessary to confirm diagnosis. The World Health Organisation WHO classification (2001) incorporates theses approaches. The purpose of this study is a bio-clinical review according to the WHO recommendations in 153 cases of LAM diagnosed between January 1998 and December 2003. The patients were aged 2 months to 90 years with sex ratio (M/F) of 1,22. The morphologic conclusion was difficult in 12% cases. Presence of dysplasia is noted in 50% of cases with multilineage dysplasia in 42% of cases. Our results showed cloned chromosomal abnormalities in 57% of cases (t(8;21): 12%, t(15;17) : 10%, Inv16: 1,3%, 11q23: 2,6% et complex karyotype: 14,3%). In 69% of cases with multilineage dysplasia, the karyotype was normal. 3 cases of LAM were noted at patients treated for breast cancer with chirurgic chemotherapy and radiotherapy 3, 4 et 5 years after treatment (LAM3 with t(15;17), LAM4 with genetic abnormalities of chromosomes 3, 5, 7, 8, 9, 14 et 16 et LAM 6 with genetic abnormalities of chromosomes 4, 7, 12, 14, 19 et 21). In WHO classification, cytology is essential in diagnosis of LAM even if the karytype have an important prognostic value. Research of signs of dysplasia lineage after lineage constitutes an important microscopic work and it is difficult to quantify dysplasia when the lineage is poor.

Soluble HLA-G molecules increase during acute leukemia, especially in subtypes affecting monocytic and lymphoid lineages

Human leukocyte antigen G (HLA-G) molecules exhibit immunomodulatory properties corresponding to nonclassic class I genes of the major histocompatibility complex. They are either membrane-bound or solubly expressed during certain tumoral malignancies. Soluble human leukocyte antigen G (sHLA-G) molecules seem more frequently expressed than membrane-bound isoforms during hematologic malignancies, such as lymphoproliferative disorders. Assay of these molecules by enzyme-linked immunosorbent assay in patients suffering from another hematologic disorder (acute leukemia) highlights increased sHLA-G secretion. This increased secretion seems more marked in acute leukemia subtypes affecting monocytic and lymphoid lineages such as FABM4 and FABM5, as well as both B and T acute lymphoblastic leukemia (ALL). Moreover, this study uses in vitro cytokine stimulations and reveals the respective potential roles of granulocyte-macrophage colony-stimulating factor and interferon-gamma in increasing this secretion in FABM4 and ALL. Correlations between sHLA-G plasma level and clinical biologic features suggest a link between elevated sHLA-G level and 1) the absence of anterior myelodysplasia and 2) high-level leukocytosis. All these findings suggest that sHLA-G molecules could be a factor in tumoral escape from immune survey during acute leukemia.

Detection of the JAK2(V617F) mutation in myeloproliferative disorders by melting curve analysis using the LightCycler system

CONTEXT

A specific mutation, JAK2(V617F), was recently recognized as having diagnostic value for myeloproliferative disorders. No practical assay is currently available for routine use in a clinical laboratory.

OBJECTIVE

We report the development of a real-time polymerase chain reaction melting curve analysis assay that is appropriate for molecular diagnostics testing.

DESIGN

Specific primers and fluorescence resonance energy transfer probes were designed, and patients with a previously diagnosed myeloproliferative disorder, de novo acute myeloid leukemia, or reactive condition were selected. The DNA was extracted from fresh and archived peripheral blood and bone marrow specimens, and real-time polymerase chain reaction melting curve analysis was performed on the LightCycler platform (Roche Applied Science, Indianapolis, Ind).

RESULTS

The JAK2 region was successfully amplified, and wild-type amplicons were reproducibly discriminated from JAK2(V617F) amplicons. Titration studies using homozygous wild-type and mutant cell lines showed the relative areas under a melting curve were proportional to allele proportion, and the assay reliably detected one mutant in 20 total cells. JAK2(V617F) was identified in patients previously diagnosed with a myeloproliferative disorder or acute myeloid leukemia transformed from myeloproliferative disorder, whereas a wild-type genotype was identified in patients with reactive conditions or de novo acute myeloid leukemia.

CONCLUSIONS

These findings demonstrate the suitability of this assay for identifying JAK2(V617F) in a clinical laboratory setting. Furthermore, the semiquantitative detection of JAK2(V617F) in archived specimens provides a new tool for studying the prognostic significance of this mutation.