A novel t (5; 17) (q35; q21) associated with t (8; 21) (q22; q22) in a patient with acute myeloid leukemia: case report and review of literature

The t (8; 21) (q22; q22) with the resulting RUNX1- RUNX1T1 rearrangement is one of the most common cytogenetic abnormalities in acute myeloid leukemia (AML). It is associated with favorable prognosis. The t (5; 17) (q35; q21) is an uncommon translocation, fuses the gene for the nucleophosmin (NPM) to the retinoic acid receptor α(RARA) and was described essentially in acute promyelocytic leukemia (APL) variant. We present the case of a 19-year-old male patient who developed an AML with t (8; 21) (q22; q22) associated to t (5; 17) (q35; 21). Morphology and immunophenotype of the leukemic cells were compatible with AML. The patient received chemotherapy based on cytarabine and anthracycline without all-trans retinoic acid (ATRA) followed by allogenic stem cell transplantation in first remission. To the best of our knowledge, this is the first report of an association between a rare translocation t (5; 17) and t (8; 21) in AML. In this report, we will discuss the prognosis of this association as well as the treatment.

Human herpesvirus-8 infection in Tunisian adult acute leukemia patients

Background

Human herpesvirus 8 (HHV-8) has been linked to the development of Kaposi's sarcoma (KS)and multiple other hematologic malignant disorders. However, the role of HHV-8 in acute leukemia patients is unknown.

Objectives

The objective of this study was to determine the prevalence of HHV-8 in Tunisian acute leukemia patients and in healthy blood donors.

Methods

An indirect immunofluorescence test was used to detect the presence of anti-HHV8 antibodies. Nested PCR was used for the detection of HHV-8 DNAemia in samples of plasma.

Results

The seroprevalence of HHV-8 was significantly higher in acute leukemia patients (21,4% ,15/70) than in healthy blood donors (7,1%, 5/70), (p= 0.02). Gender, type of disease, status of disease, prior blood transfusion, and outcome were not associated with HHV-8 seroprevalence. However, among acute leukemia patients, HHV-8 seroprevalence was statistically associated with older age > 40 years of age, (p=0.002). HHV-8 DNAemia was detected (1,4%) in only one patient of acute myeloid leukemia (AML) and none of the healthy blood donors.

Conclusions

The seroprevalence of HHV-8 infection in Tunisian adult acute leukemia patients was three times as high compared to healthy blood donors, suggesting that patients with acute leukemia might be at increased risk of HHV-8 infection.

A Phase 3 Trial of Luspatercept in Patients with Transfusion-Dependent β-Thalassemia

BACKGROUND

Patients with transfusion-dependent β-thalassemia need regular red-cell transfusions. Luspatercept, a recombinant fusion protein that binds to select transforming growth factor β superfamily ligands, may enhance erythroid maturation and reduce the transfusion burden (the total number of red-cell units transfused) in such patients.

METHODS

In this randomized, double-blind, phase 3 trial, we assigned, in a 2:1 ratio, adults with transfusion-dependent β-thalassemia to receive best supportive care plus luspatercept (at a dose of 1.00 to 1.25 mg per kilogram of body weight) or placebo for at least 48 weeks. The primary end point was the percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval. Other efficacy end points included reductions in the transfusion burden during any 12-week interval and results of iron studies.

RESULTS

A total of 224 patients were assigned to the luspatercept group and 112 to the placebo group. Luspatercept or placebo was administered for a median of approximately 64 weeks in both groups. The percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval was significantly greater in the luspatercept group than in the placebo group (21.4% vs. 4.5%, P<0.001). During any 12-week interval, the percentage of patients who had a reduction in transfusion burden of at least 33% was greater in the luspatercept group than in the placebo group (70.5% vs. 29.5%), as was the percentage of those who had a reduction of at least 50% (40.2% vs. 6.3%). The least-squares mean difference between the groups in serum ferritin levels at week 48 was -348 μg per liter (95% confidence interval, -517 to -179) in favor of luspatercept. Adverse events of transient bone pain, arthralgia, dizziness, hypertension, and hyperuricemia were more common with luspatercept than placebo.

CONCLUSIONS

The percentage of patients with transfusion-dependent β-thalassemia who had a reduction in transfusion burden was significantly greater in the luspatercept group than in the placebo group, and few adverse events led to the discontinuation of treatment. (Funded by Celgene and Acceleron Pharma; BELIEVE ClinicalTrials.gov number, NCT02604433; EudraCT number, 2015-003224-31.).

Changes in health-related quality of life with long-term eltrombopag treatment in adults with persistent/chronic immune thrombocytopenia: Findings from the EXTEND study

Patients with persistent/chronic immune thrombocytopenia (cITP) have low platelet counts, increased risk of bleeding and bruising, and often suffer from reduced health‐related quality of life (HRQoL). cITP treatments may either improve HRQoL by increasing platelet counts or decrease it because of side effects. The open‐label EXTEND study (June 2006 to July 2015) evaluated long‐term safety, tolerability, and efficacy of eltrombopag (an oral thrombopoietin‐receptor‐agonist) in adults with cITP who completed a previous eltrombopag ITP trial. The final results of EXTEND were published and used to assess changes in patient‐reported HRQoL over time and association between HRQoL and platelet response. Four validated HRQoL instruments were administered: SF‐36v2 including physical component summary (PCS) and Mental Component Summary; Motivation and Energy Inventory Short Form (MEI‐SF); Fatigue Subscale of FACIT (FACIT‐Fatigue); and FACT‐Thrombocytopenia Subscale Six‐Item Extract (FACT‐Th6). For the 302 patients enrolled, median duration of eltrombopag treatment was 2.37 years. All 4 HRQoL instruments demonstrated positive mean changes from baseline over time adjusted for patient baseline characteristics and rescue therapy use, and had positive association with platelet response (platelet count ≥30 × 10⁹/L; ≥50 × 10⁹/L; and ≥50 × 10⁹/L and >2 times baseline). Improvements from baseline started within 3 months and persisted through 5 years of treatment for FACIT‐Fatigue and FACT‐Th6 (P <.05 for nearly all time points); through 2.5 years for SF‐36v2 PCS and less consistently for the MEI‐SF. In conclusion, in addition to eltrombopag increasing platelet counts and reducing bleeding/bruising, it also alleviated fatigue, concerns about bleeding and bruising, and improved physical function in many patients, especially responders.

Cytokine and cellular responses to human herpesvirus-6B in patients with B-acute lymphoblastic leukemia

Primary infection with human herpesvirus-6 (HHV-6), is followed by its lifelong persistence in the host. Most T-cell responses to HHV-6 have been characterized using peripheral blood from healthy adults; however, the role of HHV-6 infection in immune modulation has not been elucidated for some diseases. Therefore, in this study the immune response to HHV-6 infection in patients with B-acute lymphoblastic leukemia (B-ALL) was analyzed. HHV-6 load was quantified in blood samples taken at the time of diagnosis of leukemia and on remission. The same concentrations of anti- and pro-inflammatory cytokines (IL-4, IL-1, IL-6, IL-8, IL-12p70, IL-17a, TNF-α and IFN-γ) were detected in plasma samples from 20 patients with and 20 without detectable HHV-6 virus loads in blood. Characterization of T-cell responses to HHV-6 showed low specific T-cells frequencies of 2.08% and 1.46% in patients with and without detectable viral loads, respectively. IFN-γ-producing T cells were detected in 0.03%-0.23% and in 0%-0.2% of CD4+T cells, respectively. Strong production of IL-6 was detected in medium supernatants of challenged T-cells whatever the HHV-6 status of the patients (973.51 ± 210.06 versus 825.70 ± 210.81 pg/mL). However, concentrations of TNF-α and IFN-γ were low. Thus, no association between plasma concentrations of cytokines and detection of HHV-6 in blood was identified, suggesting that HHV-6 is not strongly associated with development of B-ALL. The low viral loads detected may correspond with latently infected cells. Alternatively, HHV-6B specific immune responses may be below the detection threshold of the assays used.

Minimal residual disease detection in Tunisian B-acute lymphoblastic leukemia based on immunoglobulin gene rearrangements

IGH gene rearrangement and IGK-Kde gene deletion can be used as molecular markers for the assessment of B lineage acute lymphoblastic leukemia (B-ALL). Minimal residual disease detected based on those markers is currently the most reliable prognosis factor in B-ALL. The aim of this study was to use clonal IGH/IGK-Kde gene rearrangements to confirm B-ALL diagnosis and to evaluate the treatment outcome of Tunisian leukemic patients by monitoring the minimal residual disease (MRD) after induction chemotherapy. Seventeen consecutive newly diagnosed B-ALL patients were investigated by multiplex PCR assay and real time quantitative PCR according to BIOMED 2 conditions. The vast majority of clonal VH-JH rearrangements included VH3 gene. For IGK deletion, clonal VK1f/6-Kde recombinations were mainly identified. These rearrangements were quantified to follow-up seven B-ALL after induction using patient-specific ASO. Four patients had an undetectable level of MRD with a sensitivity of up to 10-5. This molecular approach allowed identification of prognosis risk group and adequate therapeutic decision. The IGK-Kde and IGH gene rearrangements might be used for diagnosis and MRD monitoring of B-ALL, introduced for the first time in Tunisian laboratories.

Tunisian adult's Hodgkin lymphoma Study Group

The Tunisian adult's Hodgkin lymphoma (HL) Study Group was created in 1999. It aimed to improve the management of this curable hematologic malignancy by standardizing the diagnosis, assessment of disease, treatment management and therapeutic evaluation in different Tunisian centers (Hematology, oncology and radiotherapy).Since 1998, four versions of the prospective national protocol for treating adult Hodgkin lymphoma have succeeded (MDH99, MDH2002, MDH2008, MDH2015). Each version was based on the results of the previous version and analyzed according to new data from the literature. Due to this national study group, the number of patients lost to follow decreased significantly (30% before the creation of the group and only 3% for patients treated with MDH2008), the complete and uncertain response rates have improved (75% before the creation of the group and 92% in patients treated with MDH2008) with dramatically improved rates of overall survival from 57% to 90%. On the other hand there was an improvement of toxic death rate (13% of toxic deaths in MDH2002 to 4.37% in the MDH2008) with a decrease of the respective rate of primary failure and relapse by 17% and 12.5% in MDH2002 against the 11.4% and 7.8% in the MDH2008. This resulted in an improvement in overall survival (90%) and event-free survival at 5 years (75%). Now with the introduction of positron emission tomography in Tunisia, we hope yet to finalize the assessment of response and thus better adapt the treatment of this disease. Our objective remains the improvement of event-free survival rate to reach 80%.

Combined IKZF1 and IG markers as new tools for diagnosis and minimal residual disease assessment in Tunisian B-ALL

INTRODUCTION

The monitoring of minimal residual disease (MRD) approach in patients diagnosed with B-acute lymphoblastic leukemia (B-ALL) allows an early detection of residual clones inducing relapses and therefore appropriate therapy strategy. The molecular markers may identify and quantify the residual blasts in B-ALL with normal cytology. In this study, we aimed to use combined IKZF1, IGH and IGK immunoglobulin genes for diagnosis and MRD monitoring in B-ALL sample using MLPA, multiplex PCR and real-time quantitative PCR.

MATERIAL

We showed that multiplex PCR and MLPA are necessary and complementary to detect IKZF1 deletions.

RESULTS

We have identified at the diagnosis clonal IGH rearrangement (VH3-JH5) and IKZF1 deletion (Δ4-7), which we have used it for MRD evaluation after induction chemotherapy. Despite the absence of chromosome abnormality, the patient may be classified in high-risk group with a relapse rate of residual blasts>10^-4 and sensitivity up to 10^-5. This molecular approach enabled the patient's stratification, which was overlooked by classical methods.

CONCLUSION

The combined IKZF1 and immunoglobulin genes will be used as appropriate molecular tools for diagnosis and MRD assessment of B-lineage leukemias and introduced as a routine tests in Tunisian clinical laboratories. They will be useful to stratify patients into risk groups leading to better treatment strategy.

Microsatellite Typing of Aspergillus flavus Strains in a Tunisian Onco-hematology Unit

Aspergillus flavus is the most common species associated with invasive aspergillosis in Tunisia. The molecular epidemiology of the species is poorly documented. We used five highly discriminative microsatellite markers for the genotyping of clinical and hospital environmental A. flavus strains to assess whether IA could be hospital-acquired in the onco-hematology unit of the Farhat Hached teaching hospital of Sousse, Tunisia. The genotyping of 18 clinical isolates, collected from sputa of 17 acute leukemia patients, and 81 isolates, collected in these patients' hospital environment and food, identified 57 isolates that were grouped in 10 clones, each of them including 2-17 isolates. The remaining 42 isolates showed a unique genotype. Two main transmission scenarios were observed: (1) the same clone was isolated from different patients; (2) the same clone was isolated from a patient, its hospital environment and/or food. These findings strongly suggest the occurrence of hospital-acquired A. flavus infection/colonization in the investigated onco-hematology unit.

Rituximab as second-line treatment for adult immune thrombocytopenia (the RITP trial): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Immune thrombocytopenia is characterised by immune-mediated destruction and suboptimum production of platelets. Despite the absence of supporting evidence, rituximab is frequently used off-label in patients with immune thrombocytopenia. We aimed to assess the efficacy of rituximab as compared with placebo as a splenectomy-sparing treatment in patients who were previously treated with corticosteroids.

METHODS

In this multicentre, randomised, double-masked, placebo-controlled trial, we enrolled corticosteroid unresponsive adult patients (aged ≥18 years) with primary immune thrombocytopenia and a platelet count of less than 30 × 10(9) platelets per L. Patients were randomly assigned (1:1) to four weekly infusions of 375 mg/m(2) rituximab or placebo. Concurrent treatment with corticosteroids only was allowed during the study. The primary endpoint was rate of treatment failure within 78 weeks--a composite of splenectomy or meeting criteria for splenectomy after week 12 if splenectomy was not done, assessed in all patients who received at least one dose of study treatment. Secondary endpoints were response rates, relapse rates, and duration of response. Efficacy endpoints were assessed with the Kaplan-Meier method. Safety endpoints were assessed in all patients who received at least one dose. This trial is registered with ClinicalTrials.gov, number NCT00344149.

FINDINGS

Between Aug 17, 2006, and June 30, 2011, we enrolled 112 patients. 32 (58%) of 55 patients in the rituximab group and 37 (69%) of 54 patients in the placebo group had treatment failure within 78 weeks (Kaplan-Meier cumulative incidence 46% for rituximab vs 52% for placebo (hazard ratio [HR] 0·89, 95% CI 0·55-1·45; p=0·65). The cumulative incidence of overall response was 81% in the rituximab group versus 73% in the placebo group (p=0·15) and complete response was 58% in the rituximab group versus 50% in the placebo group (p=0·12). Of those achieving an overall response, 68% relapsed in the rituximab group and 78% relapsed in the placebo group, and of those achieving complete response, 50% relapsed in the rituximab group and 62% relapsed in the placebo group. Time to relapse in the rituximab group was longer in patients who achieved overall response (36 vs 7 weeks; p=0·01) but not complete response (76 vs 49 weeks; p=0·19). Rates of bleeding were similar in the two groups (21 [38%] in the rituximab group vs 27 [50%] in the placebo group; p=0·08) as were rates of infection (22 [40%] vs 13 [24%]; p=0·09).

INTERPRETATION

Despite no reduction in the rate of long-term treatment failure with rituximab, a small benefit cannot be ruled out, as suggested by an apparently longer duration of response and numerically higher response rates with rituximab.

FUNDING

South-East Regional Health Authority and Østfold Hospital, Norway; Roche, France; and Roche, Norway.

Hospital environment fungal contamination and aspergillosis risk in acute leukaemia patients in Sousse (Tunisia)

Hospital environment is considered the main source of invasive aspergillosis (IA) in leukemic patients. This study aimed to describe Aspergillus colonisation in leukemic patients and their hospital environment and to test whether Aspergillus environmental contamination was associated with IA. For a 2-year period including 14-month renovation work, 91 acute leukaemia inpatients at the hematology department of University hospital in Sousse (Tunisia) were prospectively included. The incidence of probable IA (EORTC/MSG criteria) was 9.9%. Fifty-six Aspergillus were isolated from 53 (6.5%) of 811 sputa collected from 35 (38.5%) patients. Aspergillus spp. were isolated in 59.7% of 494 air samples and in 52.8% of 1579 surface samples taken in the patients' room. Aspergillus section Nigri (72.7%) was the most frequent. Aspergillus contamination peaked in autumn and winter on surface and in summer and autumn in air samples and was higher (P = 0.03) during the renovation work period. Multivariate analysis showed that for each Aspergillus section Nigri CFU airborne contamination IA risk increased by 1.05 (P = 0.04). In Tunisia, Aspergillus section Nigri and Flavi, but not Fumigati, are chiefly involved in IA. Our findings support swift implementation of airborne fungal contamination control measures in areas where immunocompromised patient are hospitalised.

Quantitative analysis of human herpesvirus-6 and human cytomegalovirus in blood and saliva from patients with acute leukemia

Human herpesvirus-6 (HHV-6) and human cytomegalovirus (HCMV) DNAs were quantified by real-time PCR assays in blood and saliva obtained from 50 patients with acute leukemia at the time of diagnosis (50 of each matrix), aplasia (65 of each matrix), remission (55 of each matrix), and relapse (20 of each matrix) to evaluate which biological matrix was more suitable to identify a viral reactivation, search for a possible link between HHV-6 and HCMV reactivations, and evaluate the relations between viral loads and count of different leukocyte types in blood. The median HHV-6 loads were 136; 219; 226, and 75 copies/million cells in blood at diagnosis, aplasia, remission and relapse, respectively. The HCMV loads were 193 and 317 copies/million cells in blood at diagnosis and remission. In the saliva samples, the HHV-6 loads were 22,165; 15,238; 30,214, and 17,454 copies/million cells at diagnosis, aplasia, remission, and relapse, respectively. The HCMV loads were 8,991; 1,461; 2,980, and 4,283 copies/million cells at diagnosis, aplasia, remission, and relapse, respectively. The HHV-6 load in the blood was correlated to the counts of polymorphonuclear leukocytes (R(2)  = 0.5; P < 0.0001) and lymphocytes (R(2)  = 0.4; P = 0.001) and was not correlated to the monocyte counts (R(2)  = 0.07; P = 0.7). Saliva appears to be a more sensitive biological matrix than whole blood in the detection of HHV-6 or HCMV reactivations. The HHV-6 and HCMV reactivations were linked only in saliva.

In vitro susceptibility to amphotericin B, itraconazole, voriconazole, posaconazole and caspofungin of Aspergillus spp. isolated from patients with haematological malignancies in Tunisia

The resistance of Aspergillus species to antifungal is increasingly reported and the knowledge of the local epidemiology and antifungal susceptibility pattern is pivotal to define adequate treatment policies. Our study aimed to: 1) describe the in vitro antifungal susceptibility profile of the Aspergillus species isolated from patients with haematological malignancies in Tunisia; 2) compare the E-test and Sensititre Yeast-One assays for the detection of paradoxical growth and trailing effect, both phenotypes commonly exhibited by Aspergillus spp. upon exposure to caspofungin and 3) to evaluate the mortality rate in patients according to the causative Aspergillus species and the antifungal treatment.

We tested amphotericin B, itraconazole, voriconazole, posaconazole and caspofungin against 48 Aspergillus isolates (17, A. niger; 18, A. flavus; 9, A. tubingensis; 1, A. westerdijkiae; and 1, A. ochraceus) with the E-test. Minimal inhibition concentrations were above the epidemiological cut-off values for amphotericin B in 67% of A. flavus strains; for caspofungin in 22% of A. flavus strains; and for itraconazole in 22% of A. tubingensis strains, voriconazole and posaconazole MICs were below the epidemiological cut-off values for all strains.

When exposed to caspofungin, 42% of the strains exhibited trailing effect and 38% paradoxical growth. Trailing effect occurred in 61% of A. flavus strains and paradoxical growth in 62% of Aspergillus section Nigri strains. E-test and Sensititre Yeast-One assays were only fairly concordant for the detection of these phenotypes. Repeatability of both assays was high for trailing effect but poor for paradoxical growth. The relatively high frequency of amphotericin B resistant strains makes voriconazole best adapted as a first-line treatment of invasive aspergillosis from amphotericin B to voriconazole in this hospital.

Broadband evolution of phononic-crystal-waveguide eigenstates in real- and k-spaces

Control of sound in phononic band-gap structures promises novel control and guiding mechanisms. Designs in photonic systems were quickly matched in phononics, and rows of defects in phononic crystals were shown to guide sound waves effectively. The vast majority of work in such phononic guiding has been in the frequency domain, because of the importance of the phononic dispersion relation in governing acoustic confinement in waveguides. However, frequency-domain studies miss vital information concerning the phase of the acoustic field and eigenstate coupling. Using a wide range of wavevectors k, we implement an ultrafast technique to probe the wave field evolution in straight and L-shaped phononic crystal surface-phonon waveguides in real- and k-space in two spatial dimensions, thus revealing the eigenstate-energy redistribution processes and the coupling between different frequency-degenerate eigenstates. Such use of k-t space is a first in acoustics, and should have other interesting applications such as acoustic-metamaterial characterization.

A novel t(3;12)(q21;p13) translocation in a patient with accelerated chronic myeloid leukemia after imatinib and nilotinib therapy

The acquisition of secondary chromosomal aberrations in chronic myeloid leukemia (CML) patients with Philadelphia chromosome-positive (Ph+) karyotype signifies clonal evolution associated with the progression of the disease to its accelerated or blastic phase. Therefore, these aberrations have clinical and biological significance. T(3;12)(q26;p13), which is a recurrent chromosomal aberration observed in myeloid malignancies, is typically associated with dysplasia of megakaryocytes, multilineage involvement, short duration of any blastic phase, and extremely poor prognosis. We have identified a recurrent reciprocal translocation between chromosomes 3 and 12 with different breakpoint at bands 3q21 in the malignant cells from a 28-year-old man. The patient was initially diagnosed as having Ph+ CML in the chronic phase. The t(3;12)(q21;p13) translocation occurred 4 years after the patient was first diagnosed with CML while undergoing tyrosine kinase inhibitor therapy. We confirmed the t(3;12)(q21;p13) translocation via fluorescence in situ hybridization assay by using whole-chromosome paint probes for chromosomes 3 and 12. Our findings demonstrate that, similar to other recurrent translocations involving 3q26 such as t(3;3) and t(3;21), the t(3;12)(q21;p13) translocation is implicated not only in myelodysplastic syndrome and acute myeloid leukemia but also in the progression of CML. These findings extend the disease spectrum of this cytogenetic aberration.

Chronic myeloid leukemia as a secondary malignancy after lymphoma in a child. A case report and review of the literature

BACKGROUND

Philadelphia chromosome-positive chronic myeloid leukemia (CML) in children is very rare. CML occurring as a secondary malignancy in individuals treated for diffuse large B-cell lymphoma (DLBCL) is also rare.

CASE REPORT

We present the case of a 5-year-old female patient who developed a right orbital mass that was diagnosed as DLBCL. 9 months after receiving treatment for DLBCL, she presented with a white cell count of 250,000/mm(3). Peripheral blood and bone marrow (BM) evaluation revealed a myeloproliferative disorder. Cytogenetic and molecular studies demonstrated the presence of t(9;22). CML following DLBCL has not been previously described in the younger population. To our knowledge, this is the first report of a child who developed a CML as a second malignancy after DLBCL. Therapy-related CML and non-therapy-related secondary CML are discussed as potential explanations of this highly unusual clinical presentation.

CONCLUSION

Hematological disorders such as CML may occur after lymphomas. With the increased use of BM cytogenetic studies during staging for lymphoid malignancies, future studies may be able to clarify the question of whether the CML clone in some of these patients existed before treatment for lymphoma.

Comprehensive analysis of BCR/ABL variants in chronic myeloid leukemia patients using multiplex RT-PCR

BACKGROUND

A specific chromosomal abnormality, the Philadelphia chromosome (Ph), is present in 90 - 95% of patients with chronic myeloid leukemia (CML). This aberration results from a reciprocal translocation between chromosomes 9 and 22, creating a BCR/ABL fusion gene. The diagnosis of CML is based on the detection of BCR/ABL gene or Ph chromosome. Fusion proteins with different sizes are encoded depending on the breakpoint in the BCR gene. In general, 3 breakpoint cluster regions in the BCR gene have been described: major (M-bcr), minor (m-bcr), and micro (micro-bcr). The aim of this study was to search the BCR/ABL fusion gene in 60 Tunisian patients using multiplex reverse transcription polymerase chain reaction (RT-PCR) and compare our results with those of conventional cytogenetics.

METHODS

Bone marrow (BM) or peripheral blood (PB) samples, obtained at diagnosis, from 60 patients were analyzed by multiplex RT-PCR and conventional cytogenetics.

RESULTS

45 patients examined were positive for some type of BCR/ABL rearrangement. The majority of the patients (97.77%) expressed one of the p210 BCR-ABL transcripts (63% with b3a2 and 36% with b2a2) while only one patient showed a rare e19a2 transcript.

CONCLUSIONS

Multiplex RT-PCR is a fast and reliable technique for improved detection of typical and atypical BCR/ABL transcripts.

Molecular cytogenetic characterization of Philadelphia-negative rearrangements in chronic myeloid leukemia patients

BACKGROUND

The BCR/ABL gene rearrangement is generated by a reciprocal translocation t(9;22)(q34;q11) in chronic myeloid leukemia (CML) patients. In most cases, it is cytogenetically visualized by the Philadelphia (Ph) chromosome. About 5-10% of CML patients lack cytogenetic evidence of the Ph translocation but show BCR/ABL fusion by fluorescence in situ hybridization (FISH) or reverse transcriptase-polymerase chain reaction (RT-PCR). Deletions around the breakpoints on derivative chromosome 9 including 5'ABL and 3'BCR sequences occur in 10-15% of Ph-positive CML patients and are thought to have prognostic significance.

METHODS

We explored cryptic rearrangements involving chromosomes 9 and 22 in 3 CML patients with an apparently normal bone marrow karyotypes using multiplex RT-PCR and FISH with commercial and home-brew probes.

RESULTS

The BCR/ABL fusion transcripts were detected by RT-PCR. Using commercial FISH probes, the BCR/ABL fusion gene was found on chromosome 22 in two patients and on chromosome 9 in one patient. Consecutive FISH assays clarified the mechanism of the masked Ph chromosome: in the 3 patients, Ph rearrangement resulted from double mechanism consisting in standard translocation t(9;22)(q34;q11) followed by a second reversed translocation t(9;22)(q34;q11). One patient achieved major cytogenetic response after 6 months of imatinib therapy, and one patient had successful bone marrow transplant.

CONCLUSIONS

In this study, we have characterized three Ph-negative CML patients with cryptic BCR/ABL rearrangement generated after an uncommon mechanism involving two sequential translocations and confirm that the BCR/ABL hybrid gene may be located on other sites than 22q11. Ph-negative CML patients with BCR/ABL fusion gene have the same prognosis as patients with classical t(9;22).

Translocation t(X;10)(p10;p10): a rare chromosomal abnormality in a new born female with acute myeloid leukemia

Sex chromosomes are infrequently involved in patients with hematologic malignancies. In most instances, the abnormality is either duplication in the q arm or deletion and translocation involving the q13 and q24 regions. We report herein a rare translocation t(X;10)(p10;p10) in a newborn with 2 months and 20 days with acute myeloid leukemia (AML) (FAB, M4). Cytogenetic analysis detected a cell clone with t(X;10)(p10;p10). Thus was confirmed by FISH analysis with whole chromosome painting (WCP) specific for chromosomes X and 10. The patient was treated with chemotherapy, and a complete morphologic and cytogenetic remission was achieved. To our knowledge, our case is the first report of a neonatal AML4 with t(X; 10). The patient had an excellent early response to a salvage AML-type therapy. The prognostic significance of the t(X; 10) in this setting remains unclear. Due to the rarity of this translocation, further cytogenetic and molecular biologic studies are required to elucidate the clinical and molecular significance of this unusual karyotypic finding.

Molecular cytogenetic characterization of variant Philadelphia translocations in chronic myeloid leukemia: genesis and deletion of derivative chromosome 9

The mechanisms for the formation of variant Philadelphia (Ph) translocations that occur in 5-10% of patients with chronic myeloid leukemia (CML) are not fully characterized. Studies on the prognosis of these variant translocations have yielded conflicting results, especially regarding imatinib outcome and the status of deletions on the derivative chromosome 9. To shed light on these controversial subjects, we sought to analyze all variant translocation cases presented at diagnosis and identified in our institution between the years 2001 and 2008. Of 336 CML patients who presented at diagnosis and were studied by conventional cytogenetics and fluorescence in situ hybridization (FISH), 25 patients (7.44%) exhibited variant Ph-rearrangements. All chromosomes could be implicated in variant Ph rearrangements, with 32 breakpoints defined. Their distribution was located preferentially in the CG-richest regions of the genome. Deletions on der(9) were observed in 15 of the 25 cases (60%), a greater proportion in typical Ph translocations (12-15%). Both one- and two-step mechanisms were encountered in our series, as well as multiple-step mechanisms, which originate more complex rearrangements. Higher prevalence was observed for the two-step mechanism (56%). Proper assessment of the prognostic significance of variant translocations requires better categorization of these translocations based on their mechanisms of genesis and 9q34 deletion status.

Design guidelines of 1-3 piezoelectric composites dedicated to ultrasound imaging transducers, based on frequency band-gap considerations

Periodic piezoelectric composites are widely used for imaging applications such as biomedical imaging or nondestructive evaluation. In this paper such structures are considered as phononic crystals, and their properties are investigated with respect to periodicity. This approach is based on the investigation of band gaps, that strongly depend on the properties of the considered composites (geometry, size, nature of materials). It is motivated by the fact that band gaps in principle allow one to excite the thickness mode without exciting other parasitic propagating waves. The used plane-wave-expansion method has already been applied to periodic piezoelectric composites, but, in contrast to previous approaches, not only waves propagating in the symmetry plane of the composite are considered, but also waves propagating with a nonzero angle of incidence with this plane. The method is applied to a representative 1-3 connectivity piezocomposite in order to demonstrate its potentialities for design purposes. The evolution of band gaps is explored with respect to the wave vector component parallel to piezoelectric transducer-rod axis. All bulk waves that contribute to the setting up of plate modes in the vicinity of the thickness mode are found and identified.

Complete band gaps in two-dimensional phononic crystal slabs

The propagation of acoustic waves in a phononic crystal slab consisting of piezoelectric inclusions placed periodically in an isotropic host material is analyzed. Numerical examples are obtained for a square lattice of quartz cylinders embedded in an epoxy matrix. It is found that several complete band gaps with a variable bandwidth exist for elastic waves of any polarization and incidence. In addition to the filling fraction, it is found that a key parameter for the existence and the width of these complete band gaps is the ratio of the slab thickness, d, to the lattice period, a. Especially, we have explored how these absolute band gaps close up as the parameter d/a increases. Significantly, it is observed that the band gaps of a phononic crystal slab are distinct from those of bulk acoustic waves propagating in the plane of an infinite two-dimensional phononic crystal with the same composition. The band gaps of the slab are strongly affected by the presence of cutoff frequency modes that cannot be excited in infinite media.

[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.

Evidence for complete surface wave band gap in a piezoelectric phononic crystal

A complete surface acoustic wave band gap is found experimentally in a two-dimensional square-lattice piezoelectric phononic crystal etched in lithium niobate. Propagation in the phononic crystal is studied by direct generation and detection of surface waves using interdigital transducers. The complete band gap extends from 203 to 226 MHZ, in good agreement with theoretical predictions. Near the upper edge of the complete band gap, it is observed that radiation to the bulk of the substrate dominates. This observation is explained by introducing the concept of the sound line.

Raman-like light scattering from acoustic phonons in photonic crystal fiber

Raman and Brillouin scattering are normally quite distinct processes that take place when light is resonantly scattered by, respectively, optical and acoustic phonons. We show how few-GHz acoustic phonons acquire many of the same characteristics as optical phonons when they are tightly trapped, transversely and close to modal cut-off, inside the wavelength-scale core of an air-glass photonic crystal fiber (PCF). The result is an optical scattering effect that closely resembles Raman scattering, though at much lower frequencies. We use photoacoustic techniques to probe the effect experimentally and finite element modelling to explain the results. We also show by numerical modelling that the cladding structure supports two phononic band gaps that contribute to the confinement of sound in the core.

Identification of the translocation t(15;17) in acute myeloid leukemia (AML) initially classified as FAB M1: case report and review of the literature

We report a case of a patient aged about 53 years, who initially presented with hematological disorders (WBC: 44000/mm3, Hb: 11g/dl, Pit: 127000/mm3) without tumoral syndrome. The Wright-Giemsa stained bone marrow and peripheral blood smears showed a population of blast cells characterized by cells with high N/C and strongly basophilic cytoplasm without granules. The nuclei were predominantly round. Nuclear chromatin was fine and contained small nucleoli. Cytochemisty was positive for peroxidase activity. Immunophenotyping showed myeloid typical markers of granulocytic lineage (MP0+, CD13+, CD33+, CD117+, CD34-). The karyotype revealed the expression of t(15;17) chromosomal translocation. The diagnosis of acute myeloid leukaemia (AML) was then evoked initially. The cytological features corresponded closely to the M1 subtype as defined in the FAB classification. The patient was treated with induction therapy according to the 7/3 protocol. One month later, he was discharged from hospital on hematological and cytogenetic remission. He died at home because of a heart attack. From the biological findings the patient was retrospectively diagnosed as having promyelocytic leukemia (hyperbasophilic form).

Guided elastic waves along a rod defect of a two-dimensional phononic crystal

It was shown that elastic waves propagating out-of-plane in a two-dimensional phononic crystal can experience full-band-gaps for nonzero values of the wave-vector component parallel to the rods. By further inserting a rod defect, it is demonstrated that modes propagating along the rod defect can be localized within the band-gaps of the phononic crystal. Such waveguide modes are exhibited for a tungsten/epoxy composite containing an aluminum nitride rod as the rod defect. It is expected that guided modes of such a structure can be excited and detected electrically owing to the piezoelectric effect.

Tunable filtering and demultiplexing in phononic crystals with hollow cylinders

Acoustic band gap (ABG) materials constituted of steel hollow cylinders immersed in water can exhibit a tunable narrow pass band (NPB) located inside their gap. We theoretically investigate, using the finite difference time domain (FDTD) method, the properties of waveguides composed of a row of hollow cylinders in a two-dimensional (2D) phononic crystal made of filled steel cylinders. These waveguides exhibit NPB's at frequencies slightly higher than their infinite periodic ABG counterpart. The frequency of the waveguide's NPB can be selected by adjusting the inner radius of the hollow cylinders or by changing the nature of the fluid that fills them. We show that a waveguide constituted of a row of hollow cylinders with different inner radii can transport waves at two different frequencies. By selectively filling the cylinders with water or mercury we have created an active device that permits the transmission of waves at one, both, or neither of these frequencies. Finally, we examine the multiplexing and demultiplexing capabilities of Y shaped waveguides constituted of hollow cylinders.