Analysis of the cellular DNA and RNA content in acute leukemias by flow cytometry

Summary In the present study bone marrow samples from 573 patients with newly diagnosed acute myeloid (AML) and lymphoblastic or undifferentiated leukemias (ALL/AUL), were analysed for their cellular DNA und DNA/RNA content, respectively, by means of flow cytometry. From 237 patients with AML 35.4% revealed aneuploid DNA stemlines. While no relation of DNA aneuploidy with other pretherapeutic parameters, including FAB subtype, white blood cell count, lactate dehydrogenase, S-phase index and percentage of blasts in the bone marrow, was observed, cases with aneuploid DNA stemlines revealed a tendency towards longer remission duration. In ALL/AUL 21.8% of 280 patients expressed DNA aneuploidies, which were less frequently found in T-cell ALL (11.1%) as compared to common(C)-ALL (21.4%) or null-cell(null)-ALL (23.5%). DNA aneuploidy was not related with other clinically defined risk factors such as age, white blood cell count, and rapid achievement of remission. Patients with DNA indices <1.0, however, tended to have shorter remissions. A significant difference in RNA indices was observed between AML and ALL/AUL with median values of 14.4 and 10.1, respectively (P<0.05). These data indicate the usefulness of flow cytometric analyses of cellular DNA and RNA content for the characterization and classification of acute leukemias, complementing the identification of clinical risk factors, immuno-phenotyping and cytogenetics.Abbreviations AML acute myeloid leukemia - ALL acute lymphoblastic leukemia - AUL acute undifferentiated leukemia - T-ALL, C-ALL and Null-ALL T-cell, common and Null-cell ALL     

Combination of fludarabine, amsacrine, and cytarabine followed by reduced-intensity conditioning and allogeneic hematopoietic stem cell transplantation in patients with high-risk acute myeloid leukemia

Sequential use of chemotherapy and reduced-intensity conditioning (RIC) with allogeneic stem cell transplantation (SCT) has been proposed to improve the treatment outcomes in patients with high-risk acute myeloid leukemia (AML). Here, we present our experience with this procedure in a cohort of 60 AML patients with primary induction failure (n?=?9); early, refractory, or ≥ second relapse (n?=?41); or unfavorable cytogenetics (n?=?10). A combination of fludarabine (30 mg/m²/day), cytarabine (2 g/m²/day), and amsacrine (100 mg/m²/day) for 4 days was used. After 3 days of rest, RIC was carried out, consisting of 4 Gy total body irradiation, antithymocyte globulin (ATG-Fresenius), and cyclophosphamide (fludarabine, amsacrine, and cytarabine (FLAMSA)-RIC protocol). Prophylactic donor lymphocyte infusions (pDLIs) were given in patients with complete remission (CR) and without evidence of graft-versus-host disease ≥120 days after SCT. The median time of neutrophil engraftment was 17 days. CR was achieved in 47 of 60 patients (78 %). Eleven patients received pDLIs resulting in long-term CR in eight of them. Non-relapse mortality after 1 and 3 years was 25 and 28 %, respectively. With a median follow-up of 37 months (range, 10–69), 3-year overall survival and 3-year progression-free survival were 42 and 33 %, respectively. In a multivariate analysis, dose of CD34(+) cells >5?×?10⁶/kg (p?=?0.005; hazard ratio (HR)?=?0.276), remission of AML before SCT (p?=?0.044; HR?=?0.421), and achievement of complete chimerism after SCT (p?=?0.001; HR?=?0.205) were significant factors of better overall survival. The use of the FLAMSA-RIC protocol in suitable high-risk AML patients results in a long-term survival rate of over 40 %.     

Repetitive genomic elements and overall DNA methylation changes in acute myeloid and childhood B-cell lymphoblastic leukemia patients

Aberrant epigenetic regulation is a hallmark of neoplastic cells. Increased DNA methylation of individual genes’ promoter regions and decreases in overall DNA methylation level are both generally observed in cancer. In solid tumors, this global DNA hypomethylation is related to reduced methylation of repeated DNA elements (REs) and contributes to genome instability. The aim of the present study was to assess methylation level of LINE-1 and ALU REs and total 5-methylcytosine (5metC) content in adult acute myeloid leukemia (AML) (n = 58), childhood B-cell acute lymphoblastic leukemia (ALL) (n = 32), as the most frequent acute leukemias in two age categories and in normal adult bone marrow and children’s blood samples. DNA pyrosequencing and ELISA assays were used, respectively. Global DNA hypomethylation was not observed in leukemia patients. Results revealed higher DNA methylation of LINE-1 in AML and ALL samples compared to corresponding normal controls. Elevated methylation of ALU and overall 5metC level were also observed in B-cell ALL patients. Differences of REs and global DNA methylation between AML cytogenetic-risk groups were observed, with the lowest methylation levels in intermediate-risk/cytogenetically normal patients. B-cell ALL is characterized by the highest DNA methylation level compared to AML and controls and overall DNA methylation is correlated with leukocyte count.     

Allogeneic hematopoietic stem cell transplantation for adult patients with mixed phenotype acute leukemia: results of a matched‐pair analysis

Adult patients with mixed phenotype acute leukemia (MPAL) have a poor prognosis, and the therapeutic role of allogeneic stem cell transplantation (allo‐SCT) for MPAL remains to be elucidated. Thus, we retrospectively assessed the efficacy of allo‐SCT for MPAL. Eighteen patients with MPAL were identified from the transplant outcome database of Kanto Study Group for Cell Therapy (KSGCT). We also selected 215 patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) as control cohorts using an optimal matching method. The 5‐yr overall survival (OS) rate of patients with MPAL was 48.1%, and patients in remission at the time of transplant showed significantly better survival than those not in remission (5‐yr OS: 71.8% vs. 0%, P = 0.001). No significant differences were seen in OS when stratifying patients according to immunophenotype, cytogenetic abnormalities, or the type of induction therapy. The 5‐yr OS rate of patients with MPAL was not significantly different compared with AML control patients (48.1% vs. 48.1%; P = 0.855) or ALL control patients (48.1% vs. 37.8%; P = 0.426). These results suggested that allo‐SCT is an effective treatment for MPAL, especially early in the disease course, and innovative transplant approaches are warranted to improve the transplant outcome of patients with MPAL who are not in remission.     

Liposomal daunorubicin,fludarabine, and cytarabine (FLAD) as bridge therapy to stem cell transplant in relapsed and refractory acute leukemia

Therapeutic options for patients with relapsed or refractory acute leukemia are still undefined and often unsatisfactory. We report the outcome of 79 patients with relapsed-refractory acute leukemia treated with fludarabine, cytarabine, and liposomal daunorubicin (FLAD regimen) followed by hematopoietic stem cell transplantation (HSCT), when clinically indicated, between May 2000 and January 2013. Forty-one patients had acute myeloid leukemia (AML), and 38 had acute lymphoblastic leukemia (ALL). Two patients with myeloid blast crises of CML and three with lymphoid blast crises were included in the AML and ALL subgroups, respectively. Median age was 48 years (range 13–77). FLAD was well tolerated with negligible, nonhematological toxicity. Six patients (7.5 %) died before response evaluation. Forty-seven patients achieved hematologic complete response (CR). Complete remission rate was 53 and 65 % among AML and ALL patients, respectively. No CR was recorded among 11 refractory AML patients. Twenty-four patients (30 %) underwent HSCT. Nine patients received stem cells from an HLA identical sibling, and 15 from an alternative donor (3 unrelated matched, 12 haploidentical sibling). Median overall survival in AML and ALL patients receiving FLAD therapy was 9 and 8 months, respectively. A 5-year projected OS for patients receiving the whole program (FLAD + HSCT) was 24 % for AML patients (median survival 43 months), 28 % for ALL patients treated in relapse (median survival 15 months), and 0 % for ALL patients treated for refractory disease. In this paper, we show that FLAD seems to be an effective bridge therapy to HSCT for a part of poor prognosis acute leukemia patients. However, prospective studies are needed to confirm our results.     

Analysis of Clinical Profile and Outcome of Tuberculosis in Patients with Acute Leukemia

Patients with acute leukemia (AL) are predisposed to develop infections including tuberculosis (TB). The risk is specifically higher in patients from TB endemic areas. Patients (≥12 years) with AL treated between January-2014 to January-2017 who developed TB were reviewed. Patients were classified into three groups: acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML) and acute promyelocytic leukemia (APML) and a systematic analysis of clinical features and outcomes was conducted. Over the study period, 26 patients of AL developed TB. The median time to diagnosis of TB was 8 weeks (0–432 weeks) following the diagnosis of AL and it was comparable between the three leukemia groups. The diagnosis of TB required alteration of anti-leukemia therapy in 26.9% patients and rescheduling in another 42.3% patients. Therapy alteration/rescheduling were more frequent in patients with AML as compared to ALL and APML (p < 0.03, <0.04). Disseminated TB was more common in AML patients (p < 0.016). ATT could be successfully administered in 86.9% patients with improvement of TB. The incidence of ATT induced hepatitis was 34.9%. Mortality was directly attributable to TB in 10% patients. Managing tuberculosis remains a challenge during treatment of acute leukemia. With this analysis, we advocate for a need of early suspicion and evaluation for TB in patients receiving treatment for acute leukemia. Rescheduling and or alteration of anticancer therapy due to TB is associated with significantly higher mortality. Therefore, in carefully selected cases, antileukemia therapy should continue after starting ATT as early as possible.     

Characterization of childhood acute leukemia with multiple myeloid and lymphoid markers at diagnosis and at relapse

To define the clinical and biologic significance of childhood acute mixed-lineage leukemia diagnosed by stringent criteria, we studied 25 cases of acute lymphoblastic leukemia expressing greater than or equal to 2 myeloid-associated antigens (My+ ALL), and 16 cases of acute myeloid leukemia expressing greater than or equal to 2 lymphoid associated antigens (Ly+ AML). These cases represented 6.1% of 410 newly diagnosed ALLs (two treatment protocols) and 16.8% of 95 AMLs (two protocols). T-lineage--associated antigens were identified in 9 of the My+ ALL cases and in 14 of those classified as Ly+ AML; all but 1 of the 19 cases that could be subclassified had an early thymocyte stage of differentiation. The My+ ALL cases had an increased frequency of French-American-British (FAB) L2 morphology (36%); the Ly+ AML cases were characterized by FAB M1 or M2 morphology, low levels of myeloperoxidase reactivity and combined populations of myeloperoxidase-positive large blasts and small blasts generally of hand-mirror morphology. Karyotypic abnormalities included t(9;22)(q34;q11) in three cases of My+ ALL, 11q23 translocations in two cases of My+ ALL, and 14q32 translocations in three My+ ALL and five Ly+ AML cases. Mixed-lineage expression lacked prognostic significance in either ALL or AML; however, the findings indicate that some patients with Ly+ AML may respond to prednisone, vincristine, and L-asparaginase after failing on protocols for myeloid leukemia. At relapse, two My+ ALLs had converted to AML and two Ly+ AMLs to ALL; one case in each group showed complete replacement of the original karyotype. Acute mixed-lineage leukemia does not adequately describe the heterogeneity of the cases identified in this study and should be replaced by a set of more restrictive terms that indicate the unique biologic features of these leukemias.     

Acute myeloid leukemia associated with FGFR1 abnormalities

Hematologic malignancies associated with FGFR1 abnormalities present in heterogeneous forms, including myeloproliferative neoplasm, acute myeloid leukemia (AML), T- or B-lineage lymphoblastic leukemia/lymphoma, and even mixed phenotype acute leukemia. In the present report, we describe three new cases of AML associated with FGFR1 abnormalities: AML with minimal differentiation with 45,XY,-7,t(8;13)(p11.2;q12), acute myelomonocytic leukemia with eosinophilia with 48,XY,t(8;9)(p11.2;q33),+19,+21, and AML with minimal differentiation with 46,XX,add(8)(p11.2). FGFR1 abnormalities were confirmed by fluorescence in situ hybridization. We reviewed the records of 19 patients reported from Asian countries, and found that approximately 40 % of cases manifested as acute leukemia associated with myeloid lineage, and 47 % were not accompanied with eosinophilia. These findings highlight the need for detection of FGFR1 abnormalities, not only in myeloproliferative disorder, but also in AML patients even without eosinophilia. The prognosis for this group of neoplasms is poor, and there is no recognized effective targeted treatment. Two patients, including our case, who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) survived. Accumulation of long-term follow-up data can help determine the allo-HSCT protocol or the need for new therapeutic trials to improve the survival rate of patients with FGFR1 abnormalities.     

Impact of pre-transplant marrow blasts on survival of allogeneic stem cell transplantation in adult acute myeloid leukemia

The aim of this study was to evaluate the impact of marrow blasts at transplant in adult acute myeloid leukemia (AML) patients. We analyzed 478 patients who underwent allogeneic stem cell transplantation (SCT). All patients were divided into five subgroups according to the percentage of blasts: <2 % (n = 361), ≥2 to<3 % (n = 64), ≥3 to <5 % (n = 28), ≥5 to <12 % (n = 11), and ≥12 % (n = 4). After a median follow-up of 59.5 months (range 3.3–125.9 months) for survivors, patients with higher marrow blasts at transplant showed lower overall survival (OS) and disease-free survival (DFS). In multivariate analyses, OS and DFS did not show significant differences with blast counts up to 12 %, compared with blast counts of <2 %; by contrast, the presence of >12 % marrow blasts was associated with significantly poorer OS and DFS. In the separate multivariate analyses by cytogenetic risk group, the impact of >12 % marrow blast on survival outcomes was observed in all risk groups. Thus, pre-transplant bone marrow status is an important prognostic factor for AML patients. In addition, the higher relapse rate in patients with >12 % marrow blasts may provide insights into the tolerable blast cell burden that can be overcome by the graft-versus leukemia effect.     

Bone marrow necrosis in acute leukemia: Clinical characteristic and outcome

Bone marrow necrosis (BMN) is characterized by infarction of the medullary stroma, leading to marrow necrosis with preserved cortical bone. In reported small series, BMN in hematological malignancies is associated with poor prognosis. We sought to find the impact of BMN on clinical outcome in a relatively larger cohort of patients with acute leukemias. Overall we evaluated 1,691 patients; 1,051 with acute myeloid leukemia (AML) and 640 with acute lymphocytic leukemia referred to our institution between 2002 and 2013. Patients with AML and acute lymphoblastic leukemia (ALL) were evaluated separately to determine the incidence of BMN, associated clinical features and its prognostic significance. At initial diagnosis, BMN was observed in 25 (2.4%) patients with AML and 20 (3.2%) patients with ALL. In AML, BMN was significantly associated with French–American–British AML M5 morphology (32% vs. 10%, P = 0.002). The complete remission (CR) rate in AML with and without BMN was 32% and 59% respectively (P = 0.008). Likewise, CR rate in ALL with BMN was also inferior, 70% vs. 92% (P = 0.005). The median overall survival (OS) in AML with BMN was significantly poorer, 3.7 months compared to 14 months without BMN (P = 0.003). Similarly, the median OS in ALL with and without BMN was 61.7 and 72 months respectively (P = 0.33). BMN is not a rare entity in AML and ALL, but is infrequent. BMN in AML and in ALL is suggestive of inferior response and poor prognosis. Am. J. Hematol. 90:769–773, 2015. © 2015 Wiley Periodicals, Inc.     

Feasibility of clofarabine cytoreduction followed by haploidentical hematopoietic stem cell transplantation in patients with relapsed or refractory advanced acute leukemia

Clofarabine is a novel purine nucleoside analogue with immunosuppressive and anti-leukemic activity in acute lymphoblastic and myeloid leukemia (AML, ALL). This retrospective study was performed to evaluate the feasibility and anti-leukemic activity of a sequential therapy using clofarabine for cytoreduction followed by conditioning for haploidentical hematopoietic stem cell transplantation (HSCT) in patients with non-remission acute leukemia. Patients received clofarabine (5?×?30 mg/m² IV) followed by a T cell replete haploidentical transplantation for AML (n?=?15) or ALL (n?=?3). Conditioning consisted of fludarabine, cyclophosphamide plus either melphalan, total body irradiation or treosulfan/etoposide. High-dose cyclophosphamide was administered for post-grafting immunosuppression. Neutrophil engraftment was achieved in 83 % and complete remission in 78 % at day +30. The rate of acute graft versus host disease (GvHD) grade II–IV was 22 %, while chronic GvHD occured in five patients (28 %). Non-relapse mortality (NRM) after 1 year was 23 %. At a median follow-up of 19 months, estimated overall survival and relapse-free survival at 1 year from haploidentical HSCT were 56 and 39 %, respectively. Non-hematological regimen-related grade III–IV toxicity was observed in ten patients (56 %) and included most commonly transient elevation of liver enzymes (44 %), mucositis (40 %), and skin reactions including hand-foot syndrome (17 %), creatinine elevation (17 %), and nausea/vomiting (17 %). The concept of a sequential therapy using clofarabine for cytoreduction followed by haploidentical HSCT proved to be feasible and allows successful engraftment, while providing an acceptable toxicity profile and anti-leukemic efficacy in patients with advanced acute leukemia. NRM and rate of GvHD were comparable to results after HSCT from HLA-matched donors.     

Monoclonal antiglycophorin as a probe for erythroleukemias

A monoclonal antibody (LICR.LON.R10) specific for the major sialoglycoprotein of the erythroid cell membrane, glycophorin A (alpha), has been used to test the possibility that "cryptic" erythroleukemia may be diagnosed as acute lymphoblastic leukemia (ALL) or acute myeloblastic leukemia (AML). In addition to 27 overt erythroleukemias, 724 leukemias, including 329 ALL (103 in relapse), 205 AML, and 109 blast crises of Ph1-positive chronic myeloid leukemia, were analyzed. Twenty cases with a significant proportion of glycophorin-A-positive (gA+) cells were found; 8 of these (5 AML and 3 blast crises of chronic myeloid leukemia, CML) had an obvious erythroid component, but 12 others were diagnosed as AML (2), AMML (1), CML in myeloid blast crisis (4) or megakaryoblastic blast crisis (1), acute megakaryoblastic leukemia (2), or acute lymphoblastic leukemia (2). The latter two patients had no immunologic evidence supporting a diagnosis of ALL and were resistant to chemotherapy. We conclude that AML and ALL only very rarely express gA, and these are probably genuine "cryptic" erythroleukemias. Other gA+ leukemias (megakaryoblastic and CML blast crises) may arise from bi- or pluripotent stem cells and contain distinct and separable blast cell populations.     

Wilms’ tumor gene 1 (WT1) expression in subtypes of acute lymphoblastic leukemia (ALL) of adults and impact on clinical outcome

Wilms’ tumor gene 1 (WT1) is gaining increasing attention as a therapeutic target molecule due to its common expression in acute leukemias and its involvement in cell proliferation. Here, we reported on WT1 messenger RNA expression levels at diagnosis in a series of 238 adult acute lymphoblastic leukemia (ALL) samples of various subtypes and clinical outcome. WT1 expression was found in 219 out of 238 ALL samples (92%). Compared to a cohort of acute myeloid leukemia patients, the median WT1 expression level in ALL was significantly lower with large variations among different ALL subgroups. Specifically, WT1 expression levels were low in mature B-ALL and highest in ALL cases with co-expression of myeloid markers, making it a useful therapeutic target molecule in adult ALL with the exception of mature B-ALL. Cox regression analysis, considering ALL phenotype as well as molecular-cytogenetic subsets, revealed no independent prognostic role of WT1 expression level for disease-free and overall survival.     

Adult biphenotypic acute leukaemia: an entity with poor prognosis which is related to unfavourable cytogenetics and P-glycoprotein over-expression

Biphenotypic acute leukaemia (BAL) patients represented 8% of the 287 de novo consecutive adult acute leukaemias (23 BAL, 230 acute myeloid leukaemia (AML) and 34 acute lymphoblastic leukaemia (ALL)) referred to our department during the last 4-year period. Of these 23 BAL patients, 14 patients showed myeloid morphology and nine cases lymphoid morphology according to FAB criteria. There were no differences between lymphoid and myeloid BAL according to clinical and biological presentation and treatment outcome. We confirm the poor prognosis of BAL when compared to AML or ALL seen during the same period of time, in terms of complete remission (47%, 62% and 82% respectively, BAL v AML, NS and BAL v ALL, P  = 0.006) and 4-year overall survival (8.1%, 25.8% and 23.8% respectively, BAL v AML, P  = 0.05 and BAL v ALL, P  = 0.003). Comparing adult BAL patients with AML patients, we found an increase in poor prognostic factors: CD34⁺ phenotype (82% v 60% respectively, P  = 0.03), unfavourable karyotype (60% v 20%, P  < 0.0001) and Pgp over-expression by RT-PCR (0.705 v 0.107, P  < 0.0001) and flow cytometry (0.824 v 0.391, P  = 0.0001). MRP and LRP were not found to be poor prognostic factors. Comparing BAL patients with ALL patients, we found also an increase in poor prognostic factors: age (51 v 39, P  = 0.003) and CD34⁺ phenotype (82% v 50%, P  = 0.02). We conclude that BAL patients need a more aggressive treatment procedure, including high-dose AraC or the use of Pgp modulators for first-line therapy.     

Clinical significance of minimal residual disease in childhood acute myeloid leukemia

Many studies have assessed the clinical significance of the detection of minimal residual disease (MRD) in acute leukemia. Thus far, many studies have suggested that MRD detection to evaluate the response to chemotherapy is useful for predicting the prognosis of childhood acute lymphoblastic leukemia (ALL). However, few studies have reported on the significance of MRD in childhood acute myeloid leukemia (AML), because of small numbers of patients and limited availability of MRD markers. Therefore, we monitored MRD using currently available markers at several points during the treatment for childhood AML and tried to intensify the treatment based on the results of MRD. Thirty-one patients (26 de novo cases and 5 other cases) were examined for MRD between February 1999 and May 2002. After the first consolidation therapy (consolidation 1), the expression of Wilms tumor gene (WT1) and/or leukemia-specific fusion genes such as AML1/MTG8, PML/RAR alpha, and MYH11/CBF beta were analyzed. Patients with positive MRD but in hematological remission at that point were recommended to undergo stem cell transplantation (SCT). Positive WT1 expression (more than 10(3) copies/microgram RNA) was detected in 18 of 31 patients (58.1%) at onset. After consolidation 1 therapy, the WT1 expression became negative in 14 of 18 patients. The AML1/MTG8 fusion gene was expressed in 8 patients, PML/RAR alpha was expressed in 3 patients, and MYH11/CBF beta was expressed in 1 patient. Four of the 8 patients with AML1/MTG8 expression and all 3 with PML/RAR alpha expression also demonstrated positive WT1 expression at onset. Eight (5 de novo cases and 3 other cases) of the 31 patients had no available MRD markers. Four patients who showed pesistently high expression of WT1 after consolidation 1 therapy underwent SCT, and only 1 patient remained in complete remission (CR). Among 14 patients who became negative for WT1 expression, 6 patients received SCT for various reasons. Among 8 patients with the AML1/MTG8 fusion gene, 2 became MRD negative and 6 continued to be positive. Four of these 6 patients underwent SCT, and all but one who underwent syngeneic SCT became MRD negative. On the other hand, 1 of the 2 patients who continued on chemotherapy continued to be MRD positive, suggesting a graft-versus-leukemia effect in allogeneic SCT. All patients with the PML/RAR alpha and MYH11/CBF beta fusion gene continued to be in CR. The 3-year event-free survival in de novo AML was 69.4% +/- 9.8% (n = 26), a result that is encouraging and superior to other reported outcomes. Thus, an MRD-based treatment strategy together with conventional risk factors appears to be required for further improving the outcomes of AML.     

The effect of allogeneic stem cell transplantation on outcome in younger acute myeloid leukemia patients with minimal residual disease detected by flow cytometry at the end of post-remission chemotherapy

Minimal residual disease (MRD) levels were determined by multi-parameter flow cytometry in 45 younger adult patients ( pound60 years old) with acute myeloid leukemia (AML) in complete remission. Data were collected after induction (MRD1; n=43) and/or at the end of post-remission chemotherapy or before stem cell transplantation (SCT)(MRD2; n=31). Patients with detectable MRD2 who underwent allogeneic or autologous SCT had significantly better 5-year relapse-free survival than patients not transplanted (80%, 53% and 0%, respectively p=0.003). Therefore allogeneic SCT should be considered in younger adult AML patients with detectable MRD at the end of post-remission chemotherapy. Autologous SCT may be an alternative for patients not eligible for allogeneic SCT.     

In vitro sensitivity of leukemic cells to nucleoside derivatives in childhood acute leukemias: good activity in leukemic relapses

Nucleoside analogues such as fludarabine and cladribine are used in therapy of indolent lymphomas and leukemias in adults, while cytarabine is used mainly in protocols for acute leukemias. Mechanisms of their activity is based on inhibition of enzymes involved in DNA, RNA and protein synthesis. The objective of the study was the analysis of in vitro cellular drug sensitivity in childhood acute lymphoblastic (ALL) and myeloid (AML) leukemia. Isolated leukemic cells obtained from 264 patients, including 152 initial ALL, 45 relapsed ALL, 54 initial AML and 13 relapsed AML were tested for cytotoxicity for fludarabine, cladribine, and cytarabine by the MTT assay. Drug concentration lethal to 50% of tested cells was regarded as a value of drug resistance. Three tested nucleoside analogues showed highest cytotoxicity against initial ALL samples. Samples of relapsed ALL and initial AML were more resistant than ALL de novo ones. Unexpectedly, no differences were observed between initial and relapsed AML samples for all tested drugs, what suggests that nucleoside analogues are active drugs in relapsed AML, which is commonly regarded as a resistant disease. All tested drugs presented significant cross-resistance in each of analyzed subgroups. In summary, tested nucleoside analogues presented relatively good activity against childhood leukemias at relapse stage.     

Outcome of children with relapsed acute myeloid leukemia following initial therapy under the AML99 protocol

The outcomes of children with relapsed acute myeloid leukemia (AML) are known to be poor, but remain obscure. We retrospectively analyzed 71 patients who had relapsed following first-line treatment under the AML99 protocol. We investigated the time and site of recurrence, response to re-induction therapy, and performance of hematopoietic stem cell transplantation (HSCT) in relapsed cases, and performed a multivariate analysis to identify prognostic factors. The 5-year overall-survival (OS) rate after relapse was 37 %. Of 71 patients, three died without any anti-leukemic therapy and two underwent allogeneic HSCT. The remaining 66 patients received re-induction chemotherapy, and 33 (50 %) achieved second CR (CR2). Twenty-two of 25 (88 %) late relapse patients and 11 of 41 (27 %) early relapse patients achieved CR2 (P < 0.001). Twenty-nine CR2 cases and 35 non-CR2 cases underwent allogeneic HSCT. The 5-year OS rate was significantly higher in patients who underwent HSCT in CR2 than those in non-CR2 (66 vs. 17 %, P < 0.000001). Multivariate analysis indicated that early relapse (P < 0.05) and the positivity of the FMS-like tyrosine kinase 3—internal tandem duplication (P < 0.05) were adverse prognostic factors for survival. In conclusion, the etiology of relapsed pediatric AML needs to be elucidated and effective chemotherapy should be administered to obtain CR2.     

Monitoring of acute myeloid leukemia patients after allogeneic stem cell transplantation employing semi-automated CD34+ donor cell chimerism analysis

Determination of donor chimerism profiles in blood or bone marrow from patients with allogeneic stem cell transplantation (SCT) is useful for monitoring engraftment or predicting relapse, when specific molecular markers are lacking. CD34+ donor cell chimerism (DCC) analysis in peripheral blood samples from CD34+ acute myeloid leukemia (AML) and myleodysplastic syndrome (MDS) patients proved to be a highly sensitive diagnostic tool that is useful to detect imminent relapse significantly earlier compared to total white blood cell donor cell chimerism monitoring. However, flow-cytometric enrichment of CD34+ cells requires high efforts to human resources and equipment. We present a novel semi-automated CD34+ DCC analysis procedure—employing a magnetic cell-enrichment device, DNA extraction, and short tandem repeat profiling—without the need for flow-cytometric cell sorting. Monitoring 85 patients with AML and MDS over a period of 4 years 24 relapses were detected. Semi-automated peripheral blood CD34+ DCC was diminished below 80 % in all cases of systemic relapse. Significant decrease of the CD34+ DCC value was detected 29–42 days before overt cytological relapse. Our method provides a rapid and sensitive tool for monitoring AML and MDS patients after allogeneic SCT with regard to engraftment and early detection of relapse. Here, we propose a novel semi-automated procedure for CD34+ DCC analysis after allogeneic SCT that is simple, reliable, and therefore applicable in all hematologic laboratories.     

Ultrastructural demonstration of peroxidase expression in acute unclassified leukemias: correlation to immunophenotype and treatment outcome.

The lineage affinity of 57 cases of acute unclassified leukemias (AUL) was reevaluated by ultrastructural analysis of peroxidase expression (POEM) in combination with immunophenotyping and analysis of immunoglobulin gene configuration. Twenty-three cases of myeloid and three cases of megakaryocytic differentiation were identified by detection of ultrastructural myeloperoxidase (UMPO) and platelet peroxidase (UPPO). No significant correlation was noted between myeloid marker expression and POEM positivity, whereas presence of CD 19 or CD 24 antigen significantly correlated with POEM negativity (P = .001 and .023, respectively). Ig gene rearrangements including oligoclonal patterns were also recorded in 8 of 14 UMPO+ patients tested. Fourteen UMPO+ patients responded poorly to an ALL/AUL chemotherapy regimen with a low complete remission (CR) rate of 29% and a short median remission duration (MRD) of 5 months. The POEM- patients proved very heterogenous with respect to immunophenotype and Ig gene rearrangement. Seventeen of 21 patients tested had Ig gene rearrangements, including oligoclonal patterns. Combined data suggest that a proportion of these cases probably derive from a very immature lymphoid progenitor cell, particularly because 15 POEM- AUL patients showed a response to ALL/AUL chemotherapy comparable to that observed in patients with definitive acute lymphoblastic leukemia (ALL) (CR rate 80%, MRD 20 months). Thus, ultrastructural analysis of peroxidase expression can provide decisive prognostic information in AUL patients.