Long-term follow-up of haploidentical haematopoietic stem cell transplantation in paediatric patients with high-risk acute myeloid leukaemia: Report from a single centre

Data from 200 children with high-risk acute myeloid leukaemia who underwent their first haploidentical haematopoietic stem cell transplantation (haplo-HSCT) between 2015 and 2021 at our institution were analysed. The 4-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) were 71.9%, 62.3% and 32.4% respectively. The 100-day cumulative incidences of grade II-IV and III-IV acute graft-versus-host disease (aGVHD) were 41.1% and 9.5% respectively. The 4-year cumulative incidence of chronic GVHD (cGVHD) was 56.1%, and that of moderate-to-severe cGVHD was 27.3%. Minimal residual disease (MRD)-positive (MRD+) status pre-HSCT was significantly associated with lower survival and a higher risk of relapse. The 4-year OS, EFS and CIR differed significantly between patients with MRD+ pre-HSCT (n = 97; 63.4%, 51.4% and 41.0% respectively) and those with MRD-negative (MRD-) pre-HSCT (n = 103; 80.5%, 73.3% and 23.8% respectively). Multivariate analysis also revealed that acute megakaryoblastic leukaemia without Down syndrome (non-DS-AMKL) was associated with extremely poor outcomes (hazard ratios and 95% CIs for OS, EFS and CIR: 3.110 (1.430-6.763), 3.145 (1.628-6.074) and 3.250 (1.529-6.910) respectively; p-values were 0.004, 0.001 and 0.002 respectively). Thus, haplo-HSCT can be a therapy option for these patients, and MRD status pre-HSCT significantly affects the outcomes. As patients with non-DS-AMKL have extremely poor outcomes, even with haplo-HSCT, a combination of novel therapies is urgently needed.

Skin Manifestations of Micafungin Breakthrough Disseminated Trichosporonosis in Acute Megakaryoblastic Leukemia

Disseminated trichosporonosis is a rare fungal infection whose risk factors are hematological malignancies and neutropenia. Recently, breakthrough Trichosporon infections after administration of micafungin, the first-line systemic antifungal agent in compromised hosts, have been widely recognized. A man in his seventies about 1 month into chemotherapy for acute megakaryoblastic leukemia presented with a worsening fever and dyspnea. The patient was being administered with empirical micafungin therapy for suspected candidiasis. As the symptoms progressed, scattered erythema appeared on the trunk, some with a dark red vesicle at the center. Blood cultures identified Trichosporon asahii, as did the specimen of the skin biopsy. On the basis also of the presence of pneumonia on chest computed tomography, we confirmed the diagnosis of disseminated trichosporonosis and changed the antifungal agent from micafungin to voriconazole. Blood culture turned out to be negative 1 month after administrating voriconazole. However, the patient died of the leukemia. Our review of previous reports on cutaneous manifestations of disseminated trichosporonosis revealed that despite their morphological diversity, erythema with a red papule or vesicle at the center, implying necrosis, was also observed in previous cases. Our case report suggests that dermatologists should be aware of skin manifestations of disseminated trichosporonosis after micafungin administration, especially in cases of hematological malignancies.

Synergistic roles of DYRK1A and GATA1 in trisomy 21 megakaryopoiesis

Patients with Down syndrome (DS), or trisomy 21 (T21), are at increased risk of transient abnormal myelopoiesis (TAM) and acute megakaryoblastic leukemia (ML-DS). Both TAM and ML-DS require prenatal somatic mutations in GATA1, resulting in the truncated isoform GATA1s. The mechanism by which individual chromosome 21 (HSA21) genes synergize with GATA1s for leukemic transformation is challenging to study, in part due to limited human cell models with wild-type GATA1 (wtGATA1) or GATA1s. HSA21-encoded DYRK1A is overexpressed in ML-DS and may be a therapeutic target. To determine how DYRK1A influences hematopoiesis in concert with GATA1s, we used gene editing to disrupt all 3 alleles of DYRK1A in isogenic T21 induced pluripotent stem cells (iPSCs) with and without the GATA1s mutation. Unexpectedly, hematopoietic differentiation revealed that DYRK1A loss combined with GATA1s leads to increased megakaryocyte proliferation and decreased maturation. This proliferative phenotype was associated with upregulation of D-type cyclins and hyperphosphorylation of Rb to allow E2F release and derepression of its downstream targets. Notably, DYRK1A loss had no effect in T21 iPSCs or megakaryocytes with wtGATA1. These surprising results suggest that DYRK1A and GATA1 may synergistically restrain megakaryocyte proliferation in T21 and that DYRK1A inhibition may not be a therapeutic option for GATA1s-associated leukemias.

Mutation characterization in the GATA-1 gene in patients with Down's Syndrome diagnosed with transient abnormal myelopoiesis or acute megakaryoblastic leukemia

Patients with Down's Syndrome have a higher risk of developing acute megakaryoblastic leukemia (AML). Ten per cent of newborn infants with this syndrome have transient abnormal myelopoiesis (TAM), indistinguishable from AML, which generally remits spontaneously. A high incidence of GATA-1 gene mutations was described in both groups of patients. Fourteen bone marrow DNA samples (10 ATM/4 AML) were analyzed by PCR and sequencing; these samples were obtained from 13 patients with Down's Syndrome to describe the rate and mutation characteristics of the GATA-1 gene in the studied population and its consequences at a protein level. Mutations were detected in 10 out of 10 TAM and in 3 out of 4 AML, which at a protein level would result in an early termination codon (n= 5), alterations in the splicing site (n= 6) or sequence change (n= 3). The high rate of GATA-1 gene mutations was confirmed in newborn infants with Down's Syndrome and MAT or AML.

Acute leukemias in children with Down syndrome

Children with Down syndrome (DS) often present with hematopoietic abnormalities, and are at increased risk of developing leukemia. Specifically, 3-10% of newborns with DS are diagnosed with transient myeloproliferative disease, and children with DS are 500 times more likely to develop acute megakaryoblastic leukemia (AMKL) and 20 times more likely to develop acute lymphoblastic leukemia (ALL) than typical children. This review examines the characteristics of these leukemias and their development in the unique genetic background of trisomy 21. A discussion is also provided for areas of future research and potential therapeutic development.

Mucormycosis of the nasal ala in a leukemic (M7 AML) child. Is surgery of the nasal defect indicated?

Anterior tamponade with Surgicel (oxidized cellulose) was performed on a 5-year-old girl with megakaryoblastic leukemia (M7 AML) and epistaxis. Several days later necrosis of the nasal ala occurred. Debridement was performed and mucormycosis caused by Rhizopus was found in the material. Having cured mucormycosis, a defect of the complete nasal ala remained. The question of a surgical resolution of the disfiguring nasal defect arises.

Increased dosage of the chromosome 21 ortholog Dyrk1a promotes megakaryoblastic leukemia in a murine model of Down syndrome

Individuals with Down syndrome (DS; also known as trisomy 21) have a markedly increased risk of leukemia in childhood but a decreased risk of solid tumors in adulthood. Acquired mutations in the transcription factor-encoding GATA1 gene are observed in nearly all individuals with DS who are born with transient myeloproliferative disorder (TMD), a clonal preleukemia, and/or who develop acute megakaryoblastic leukemia (AMKL). Individuals who do not have DS but bear germline GATA1 mutations analogous to those detected in individuals with TMD and DS-AMKL are not predisposed to leukemia. To better understand the functional contribution of trisomy 21 to leukemogenesis, we used mouse and human cell models of DS to reproduce the multistep pathogenesis of DS-AMKL and to identify chromosome 21 genes that promote megakaryoblastic leukemia in children with DS. Our results revealed that trisomy for only 33 orthologs of human chromosome 21 (Hsa21) genes was sufficient to cooperate with GATA1 mutations to initiate megakaryoblastic leukemia in vivo. Furthermore, through a functional screening of the trisomic genes, we demonstrated that DYRK1A, which encodes dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1A, was a potent megakaryoblastic tumor-promoting gene that contributed to leukemogenesis through dysregulation of nuclear factor of activated T cells (NFAT) activation. Given that calcineurin/NFAT pathway inhibition has been implicated in the decreased tumor incidence in adults with DS, our results show that the same pathway can be both proleukemic in children and antitumorigenic in adults.

Pulseless right upper limb: an unusual manifestation of invasive pulmonary aspergillosis in acute myeloid leukemia

Aspergillus is the most common cause of fungal pneumonia in acute leukemia patients receiving chemotherapy or undergoing hematopoietic stem cell transplantation. Despite a high index of suspicion and prompt institution of specific antifungal therapy, it causes significant morbidity and mortality in patients with hematological malignancies. It has to be differentiated from mucormycosis because the treatment differs. Histological confirmation obtained by lung biopsy is ideal, but is difficult to obtain in those patients who often have thrombocytopenia. We report a case of acute megakaryoblastic leukemia with typical manifestations of invasive pulmonary aspergillosis who developed pulseless right arm due to invasion of the right subclavian artery. When total leucocyte counts recovered, patient also developed immune reconstitution inflammatory syndrome and massive pulmonary hemorrhage, which was managed by bronchial artery embolization.

Transcription factor GATA-1 and Down syndrome leukemogenesis

Mutations in transcription factors constitute one means by which normal hematopoietic progenitors are converted to leukemic stem cells. Recently, acquired mutations in the megakaryocytic regulator GATA1 have been found in essentially all cases of acute megakaryoblastic leukemia (AMkL) in children with Down syndrome and in the closely related malignancy transient myeloproliferative disorder. In all cases, mutations in GATA1 lead to the expression of a shorter isoform of GATA-1, named GATA-1s. Because GATA-1s retains both DNA binding zinc fingers, but is missing the N-terminal transactivation domain, it has been predicted that the inability of GATA-1s to regulate its normal class of megakaryocytic target genes is the mechanism by which mutations in GATA1 contribute to the disease. Indeed, several recent reports have confirmed that GATA-1s fails to properly regulate the growth of megakaryocytic precursors, likely through aberrant transcriptional regulation. Although the specific target genes of GATA-1 mis-regulated by GATA-1s that drive this abnormal growth remain undefined, multiple candidate genes have been identified via gene array studies. Finally, the inability of GATA-1s to promote expression of important metabolic genes, such as cytadine deaminase, likely contributes to the remarkable hypersensitivity of AMkL blasts to cytosine arabinoside. Future studies to define the entire class of genes dysregulated by mutations in GATA1 will provide important insights into the etiology of these malignancies.

Incidence and clinical implications of GATA1 mutations in newborns with Down syndrome

Somatic mutations in the GATA1 gene are present in almost all cases of Down syndrome (DS)–associated acute megakaryoblastic leukemia (AMKL) and transient leukemia (TL). An in utero origin of the GATA1 mutation suggests it is an early leukemogenic event. To determine the detectable incidence and clinical relevance of GATA1 mutations in DS newborns, we screened Guthrie cards from 590 DS infants for mutations in the GATA1 gene. Twenty-two (3.8%) of 585 evaluable infants harbored a predicted functional GATA1 mutation; 2 were identified exclusively within intron 1. Hispanic newborns were 2.6 times more likely to have a mutated GATA1 gene than non-Hispanics (P = .02). Two newborns with a GATA1 mutation subsequently developed AMKL, and none of the infants without a functional GATA1 mutation were reported to have developed leukemia. In addition to screening for TL, a GATA1 mutation at birth might serve as a biomarker for an increased risk of DS-related AMKL.

Acute myeloid leukaemia of mixed megakaryocytic and erythroid origin: a case report and review of the literature

We report the case of a 78-year-old man who presented with acute myeloid leukaemia showing subpopulations of cells expressing platelet-associated markers and the presence of a pan-myeloid component, besides glycophorin A-positive cells. Most of the immature cells had a proerythroblast-like morphology and we classified this case as an FAB-M6 variant, as suggested by Bain (1). According to the WHO classification, this leukaemia fulfilled the criteria of'AML with multilineage dysplasia' (2). Immunophenotyping characteristics showed two distinct aberrant subpopulations, a young pan-myeloid (CD45+ with low density, CD34+, CD117+, CD13+, CD33+, partial cytoplasmic myeloperoxidase (MPO)+) population with platelet-associated markers (CD41+, CD42+, CD61+) and a CD45+, CD117+, CD34- population with partial CD235a positivity indicative for erythroid maturation. This case belongs to the group of 'early' erythroblastic leukaemias where a subset of progenitor cells present with erythroid-megakaryocyte bipotentiality or are blocked at an early BFU-E (burst-forming unit erythrocyte)-like stage of erythroid differentiation (11, 12, 13).

Loss-of-function JAK3 mutations in TMD and AMKL of Down syndrome

Acquired mutations activating Janus kinase 3 (jak3) have been reported in Down syndrome (DS) and non-DS patients with acute megakaryoblastic leukaemia (AMKL). This highlighted jak3-activation as an important event in the pathogenesis of AMKL, and predicted inhibitors of jak3 as conceptual therapeutics for AMKL. Of 16 DS-transient myeloproliferative disorder (TMD)/AMKL patients tested, seven showed JAK3 mutations. Three mutations deleted the kinase (JH1) domain, abolishing the main function of jak3. Another patient displayed a mutation identical to a previously reported inherited loss-of-function causing severe combined immunodeficiency. Our data suggest that both gain-, and loss-of function mutations of jak3 can be acquired in DS-TMD/AMKL.

CD36 (thrombospondin receptor) expression in childhood acute megakaryoblastic leukemia: in vitro drug sensitivity and outcome

The outcome for children with acute megakaryoblastic leukemia (AMKL) remains poor, except for cases associated with Down syndrome (DS). This study compared immunophenotypic and drug sensitivity patterns of childhood AMKL cases with or without DS. All DS-AMKL cases showed high expression of CD36 and were very sensitive to cytarabine and daunorubicin in vitro. In children without DS, high expression of CD36 on AMKL blasts identified a sub-group with immunophenotypic and drug sensitivity patterns similar to that of DS AMKL. Among non-DS AMKL patients, CD36-high cases had a superior outcome compared with CD36-negative cases. CD36 expression in acute myeloid leukemia cases other than AMKL was not associated with increased in vitro drug sensitivity. CD36 expression in AMKL may be an indicator of megakaryoblast maturation and chemotherapy sensitivity.

Invasive esophageal aspergillosis associated with acute myelogenous leukemia: successful therapy with combination caspofungin and liposomal amphotericin B

Aspergillosis is one of the most common invasive fungal infections in patients with leukemia. In this patient group, this form of Aspergillus infection is a life-threatening condition with a mortality of 50-100%. The lungs are most often affected, but the esophagus can also be involved.The authors report the case of a child with leukemia who developed invasive esophageal aspergillosis. The condition was diagnosed by microscopic examination of endoscopic biopsy specimens. The patient was already receiving empirical liposomal amphotericin B when the diagnosis was made, so a second antifungal (caspofungin) was added to the regimen. This combination was successful. This case to demonstrates a case of successful treatment of invasive esophageal aspergillosis using combination therapy of liposomal amphotericin B and caspofungin.

Development of acute megakaryoblastic leukemia from a minor clone in a Down syndrome patient with clinically overt transient myeloproliferative disorder

A Down syndrome male showed leukocytosis from birth and was diagnosed as transient myeloproliferative disorder (TMD). Eight months later, his condition had progressed to myelodysplastic syndrome after spontaneous resolution, and it then evolved to acute megakaryoblastic leukemia (AMKL) at the age of 20 months. Sequencing analysis showed that the predominant TMD and AMKL clones had different GATA1 mutations, although a minor TMD clone identical to the AMKL clone was present at birth. These observations suggest that a minor clone rather than the predominant clone at the time of TMD may give rise to AMKL later on.

Physical association of the patient-specific GATA1 mutants with RUNX1 in acute megakaryoblastic leukemia accompanying Down syndrome

Mutations of the GATA1 gene on chromosome X have been found in almost all cases of transient myeloproliferative disorder and acute megakaryoblastic leukemia (AMKL) accompanying Down syndrome (DS). Although most GATA1 mutations lead to the expression of GATA1s lacking the N-terminal activation domain, we recently found two novel GATA1 proteins with defects in another N-terminal region. It has been suggested that loss of the N-terminal portion of GATA1 might interfere with physiological interactions with the critical megakaryocytic transcription factor RUNX1, and this would imply that GATA1s is not able to interact properly with RUNX1. However, the interaction domain of GATA1 remains controversial. In this study, we show that GATA1 binds to RUNX1 through its zinc-finger domains, and that the C-finger is indispensable for synergy with RUNX1. All of the patient-specific GATA1 mutants interacted efficiently with RUNX1 and retained their ability to act synergistically with RUNX1 on the megakaryocytic GP1balpha promoter, whereas the levels of transcriptional activities were diverse among the mutants. Thus, our data indicate that physical interaction and synergy between GATA1 and RUNX1 are retained in DS-AMKL, although it is still possible that increased RUNX1 activity plays a role in the development of leukemia in DS.

A prospective study of the natural history of transient leukemia (TL) in neonates with Down syndrome (DS): Children's Oncology Group (COG) study POG-9481

A unique transient leukemia (TL) has been described in newborns with Down syndrome (DS; or trisomy 21 mosaics). This leukemia has a high incidence of spontaneous remission; however, early death and subsequent development of acute megakaryoblastic leukemia (AMKL) have been reported. We prospectively evaluated 48 infants with DS and TL to determine the natural history and biologic characteristics of this disease, identify the clinical characteristics associated with early death or subsequent leukemia, and assess the incidence of subsequent leukemia. Blast cells associated with TL in DS infants exhibited FAB M(7) morphology and phenotype. Most infants (74%) had trisomy 21 (or mosaicism) as the only cytogenetic abnormality in the blast cells. Most children were able to spontaneously clear peripheral blasts (89%), normalize blood counts (74%), and maintain a complete remission (64%). Early death occurred in 17% of infants and was significantly correlated with higher white blood cell count at diagnosis (P < .001), increased bilirubin and liver enzymes (P < .005), and a failure to normalize the blood count (P = .001). Recurrence of leukemia occurred in 19% of infants at a mean of 20 months. Development of leukemia was significantly correlated with karyotypic abnormalities in addition to trisomy 21 (P = .037). Ongoing collaborative clinical studies are needed to determine the optimal role of chemotherapy for infants at risk for increased mortality or disease recurrence and to further the knowledge of the unique biologic features of this TL.

GATA1 as a new target to detect minimal residual disease in both transient leukemia and megakaryoblastic leukemia of Down syndrome

Acquired mutations in exon 2 of the GATA1 gene are detected in most Down syndrome (DS) patients with transient leukemia (TL) and acute megakaryoblastic leukemia (AMKL). We sought to determine if GATA1 mutations can be utilized as markers for minimal residual disease (MRD). GATA1 mutations were screened by SSCP analysis and sequenced. Using GATA1 mutation-specific primers, follow-up bone marrow samples from four patients were assayed by quantitative PCR. We show that molecular monitoring of GATA1 mutations is possible in Down syndrome patients with TL and AMKL, and GATA1 could be a stable marker for MRD monitoring.

Differential gene expression, GATA1 target genes, and the chemotherapy sensitivity of Down syndrome megakaryocytic leukemia

Children with Down syndrome (DS) with acute megakaryocytic leukemia (AMkL) have very high survival rates compared with non-DS AMkL patients. Somatic mutations identified in the X-linked transcription factor gene, GATA1, in essentially all DS AMkL cases result in the synthesis of a shorter (40 kDa) protein (GATA1s) with altered transactivation activity and may lead to altered expression of GATA1 target genes. Using the Affymetrix U133A microarray chip, we identified 551 differentially expressed genes between DS and non-DS AMkL samples. Transcripts for the bone marrow stromal-cell antigen 2 (BST2) gene, encoding a transmembrane glycoprotein potentially involved in interactions between leukemia cells and bone marrow stromal cells, were 7.3-fold higher (validated by real-time polymerase chain reaction) in the non-DS compared with the DS group. Additional studies confirmed GATA1 protein binding and transactivation of the BST2 promoter; however, stimulation of BST2 promoter activity by GATA1s was substantially reduced compared with the full-length GATA1. CMK sublines, transfected with the BST2 cDNA and incubated with HS-5 bone marrow stromal cells, exhibited up to 1.7-fold reduced cytosine arabinoside (ara-C)-induced apoptosis, compared with mock-transfected cells. Our results demonstrate that genes that account for differences in survival between DS and non-DS AMkL cases may be identified by microarray analysis and that differential gene expression may reflect relative transactivation capacities of the GATA1s and full-length GATA1 proteins.

Recombinant activated factor VII for severe gastrointestinal bleeding after chemotherapy in an infant with acute megakaryoblastic leukemia

Recombinant activated factor VII (rFVIIa) is a major alternative for management of hemophiliac patients with inhibitors. Additionally, it has been used off-label for the treatment of massive life-threatening hemorrhage associated with various bleeding situations. Herein, we describe a 16-month-old boy with acute megakaryoblastic leukemia and severe intractable gastrointestinal bleeding controlled by rFVIIa. rFVIIa should be considered as a novel treatment alternative in severe bleeding conditions including leukemias that may have hemostatic defects and platelet dysfunction.

Eyelid mass as the presenting finding in a child with Down syndrome and acute megakaryoblastic leukemia

Children with Down syndrome are at increased risk of developing acute megakaryoblastic leukemia (AML). Therefore, physicians caring for children with Down syndrome should be familiar with the presenting features of AML. We describe a child with Down syndrome presenting with a left eyelid mass 1 month before a diagnosis of acute AML.

GATA1, cytidine deaminase, and the high cure rate of Down syndrome children with acute megakaryocytic leukemia

Down syndrome children with acute megakaryocytic leukemia (AMkL) have higher cure rates than non-Down syndrome acute myeloid leukemia (AML) patients treated with cytosine arabinoside (ara-C). Megakaryoblasts from Down syndrome AML patients are more sensitive in vitro to ara-C than cells from non-Down syndrome AML patients. Somatic mutations in the GATA1 transcription factor have been detected exclusively and almost uniformly in Down syndrome AMkL patients, suggesting a potential linkage to the chemotherapy sensitivity of Down syndrome megakaryoblasts. Stable transfection of wild-type GATA1 cDNA into the Down syndrome AMkL cell line CMK resulted in decreased (8- to 17-fold) ara-C sensitivity and a threefold-lower generation of the active ara-C metabolite ara-CTP compared with that for mock-transfected CMK cells. High intracellular levels of uridine arabinoside (ara-U) (an inactive ara-C catabolite generated by cytidine deaminase) and cytidine deaminase transcripts were detected in GATA1-transfected CMK sublines, whereas no ara-U was detected in mock-transfected cells. Cytidine deaminase transcripts were a median 5.1-fold (P = .002) lower in Down syndrome megakaryoblasts (n = 16) than in blast cells from non-Down syndrome patients (n = 56). These results suggest that GATA1 transcriptionally upregulates cytidine deaminase and that the presence or absence of GATA1 mutations in AML blasts likely confers differences in ara-C sensitivities due to effects on cytidine deaminase gene expression, which, in turn, contributes to the high cure rate of Down syndrome AMkL patients.

Hematopoietic stem cell transplantation for de novo acute megakaryocytic leukemia in first complete remission: a retrospective study of the European Group for Blood and Marrow Transplantation (EBMT)

Acute megakaryoblastic leukemia (M7 AML) is a highly aggressive disease. We evaluated outcomes in 57 children (11 with Down syndrome) and 69 adults with M7 AML after first complete remission (CR1) following autologous or HLA-identical allogeneic transplantation. Characteristics of the recipients of autologous transplants (38 children, 37 adults) were, respectively: median age, 1.7 and 46 years; non-total body irradiation (non-TBI) conditioning regimen, 97% and 70%; bone marrow as stem cell source, 74% and 43%. Characteristics of the recipients of allogeneic transplants (19 children, 32 adults) were, respectively: median age, 2.8 and 37 years; non-TBI regimen, 63% and 42%; bone marrow as stem cell source, 95% and 69%. Autologous transplantation benefited children more; the relapse rate was high in adults. Results for autologous transplantation were (children and adults, respectively): engraftment, 90% and 100%; 3-year treatment-related mortality (TRM) rate, 3% and 8%; relapse rate, 45% and 64%; leukemia-free survival (LFS) rate, 52% and 27%; overall survival (OS) rate, 61% and 30%. After allogeneic transplantation, TRM was fairly low in children and adults, and relapse rates were lower than after autologous transplantation. Results for allogeneic transplantation were, respectively: engraftment, 95% and 90%; TRM, 0% and 26%; relapse rate, 34% and 28%; LFS, 66% and 46%; OS, 82% and 43%). We conclude that M7 AML patients in CR1 (except children with Down syndrome, who already have better outcomes) can benefit from transplantation. (Blood. 2005;105:405-409)

[Acute leukemia in patients with Down syndrome]

BACKGROUND

Children with Down syndrome (DS) have a higher risk of acute leukemia than the remaining pediatric population. A favorable outcome of acute myeloid leukemia (AML) has recently been described in these patients whereas the prognosis of acute lymphoblastic leukemias (ALL) is similar to that in other children. The main cause of morbidity and mortality in children with Down syndrome are complications related to chemotherapy, leading to numerous modifications in treatment protocols.

OBJECTIVES

To characterize acute leukemias in children with Down syndrome in our center and determine their clinical outcome.

METHODS AND RESULTS

Between 1990 and 2002, 214 children were diagnosed with acute leukemia at the Niño Jesus Hospital (40 with AML and 174 with ALL). Of these, eight children (3.8 %) had Down syndrome. AML (2/40) represented 5 % of myeloid leukemias and ALL (6/174) represented 3.4 % of lymphoblastic leukemias. The most frequent complication was hematologic toxicity due to chemotherapy, causing a high incidence of infections: pneumonia (5/8) and bacteriemia (5/8). In all patients, these complications led to treatment interruption or dose reduction. Two children died from treatment-related toxicity. Of these, one with AML developed fulminant sepsis due to Candida infection and the other, diagnosed with high risk ALL, died from multiorgan failure after high doses of methotrexate and ARA-C.

CONCLUSIONS

Patients with Down syndrome diagnosed with acute leukemia show a higher incidence of treatment-related complications, which affects their prognosis. Consequently, individualized treatment of these children in qualified units is essential.

Interleukin-11 as an osteoprotegerin-inducing factor in culture medium of blastic cells from a patient with acute megakaryocytic leukemia complicated with osteosclerosis

We came across a rare case of acute megakaryocytic leukemia, the clinical course of which was relatively chronic and nonaggressive. This case was complicated with generalized severe osteosclerosis (OS). The medium in which blastic cells from the patient were cultured showed a strong activity to enhance the expression of an osteosclerotic cytokine, osteoprotegerin (OPG), as revealed by real-time quantitative RT-PCR and Western blot analysis. The OPG-inducing activity of the culture medium was neutralized by the anti-interleukin-11 (IL-11) antibody. These results indicate that IL-11 produced by the blasts was a causative factor of the OS observed in this patient.

Acute megakaryoblastic leukaemia with extreme thrombocytosis and p190 bcr/abl rearrangement

Acute megakaryoblastic leukaemia (AML-M7) is an uncommon disease, composing 0.5-1.2% of newly diagnosed adult acute myeloid leukaemias (AML). It is characterised by higher incidence and complexity of cytogenetic abnormalities. We report a rare case of Philadelphia (Ph) chromosome-positive AML-M7, presenting with extreme thrombocytosis and having a poor outcome. The diagnosis was established on the basis of morphological and flow cytometry data for megakaryoblastic proliferation in the bone marrow. Cytogenetics revealed 47,XX,+8,t(9;22)(q34;q11), and p190(BCR-ABL)-rearrangement was detected. MDR1-gene overexpression was not demonstrated; however, the patient was resistant to therapy and died in 6 months. The reported case contributes to the overt heterogeneity of Ph-positive AMLs, which warrants further investigation and understanding.

Mutations in GATA1 in both transient myeloproliferative disorder and acute megakaryoblastic leukemia of Down syndrome

Mutations in transcription factors often contribute to human leukemias by providing a block to normal differentiation. To determine whether mutations in the hematopoietic transcription factor GATA1 are associated with leukemia, we assayed for alterations in the GATA1 gene in bone marrow samples from patients with various subtypes of acute leukemia. Here we summarize our findings that GATA1 is mutated in the leukemic blasts of patients with Down syndrome acute megakaryoblastic leukemia (DS-AMKL). We did not find mutations in GATA1 in leukemic cells of DS patients with other types of acute leukemia, or in other patients with AMKL who did not have DS. Furthermore, we did not detect GATA1 mutations in DNAs from over 75 other patients with acute leukemia or from 21 healthy individuals. Since the GATA1 mutations were restricted to DS-AMKL, we also investigated whether GATA1 was altered in the "preleukemia" of DS, transient myeloproliferative disorder (TMD). TMD is a common myeloid disorder that affects 10% of DS newborns and evolves to AMKL in nearly 30% patients. We detected GATA1 mutations in TMD blasts from every infant examined. Together, these results demonstrate that GATA1 is likely to play a critical role in the etiology of TMD and DS-AMKL, and that mutagenesis of GATA1 represents a very early event in DS myeloid leukemogenesis. We hypothesize that disruption of normal GATA-1 function is an essential step in the initiation of megakaryoblastic leukemia in DS.

Biology, clinical, and hematologic features of acute megakaryoblastic leukemia in children

To assess the incidence, clinical features at presentation, hematologic, immunophenotypic, and cytogenetic characteristics of AMKL in children we prospectively studied 834 consecutive non selected children with newly diagnosed acute leukemia (AL) admitted to the Hematology Department at the Instituto Nacional de Pediatría (INP), Mexico, D.F. We found 682 cases (81.8%) with a typical ALL immunophenotype, and the remaining 152 (18.2%) were considered to have AML. In 29 of the 152 patients with AML studied, a diagnosis of AMKL was established. These 29 cases represented 19.1% of the cases of AML and 3.48% of the total cases of AL during the time span covered by the study. Twenty-four percent of the cases occurred in infants 2 years old or younger and 41.4% occurred in children 41 months of age or younger. In contrast, in only 18.6% of the patients with AML (M0-M6), the diagnosis was established before 42 months of age and in 17% before their second year of life. Clinical presentation was not strikingly different than that observed in patients with other types of AML, and the time interval from onset of symptoms to diagnosis was also similar, though in a small subset of patients, the clinical course was characterized by a chronic slowly progressive disorder extending over weeks or months resembling smoldering leukemia or chronic myelofibrosis with agnogenic myeloid metaplasia. Bone marrow (BM) fibrosis was a constant features in our patients; 75% of the patients studied showed this complication at the time of diagnosis. Some rather unusual findings in this study were intense skeletal pains from multiple osteolytic lesions, the presence of soft-tissue tumor, and the presence of cohesive scanty clusters of primitive-looking blast cells in BM aspirates. Several interesting cytogenetic findings in our study were t(1;22)(p13;q13) in a 14-year-old boy, t(9;22)(q34;q11) in one patient, and monosomy 7 in two patients. Another important finding in our study was the clinical association with colonic adenocarcinoma in one patient, an association that to our knowledge has not been reported previously. In conclusion, our data suggest that the incidence of AMKL in Mexico might be higher than those reported in Caucasian white pediatric population, and that biologic and cytogenetic profile may differ from those of western countries, but more studies are needed to corroborate cytogenetic heterogeneity, ethnic and geographic diversity. Early onset of the disease, low WBC counts, slight thrombocytopenia or normal platelet counts, and BM fibrosis were characteristic distinctive features of at least half of the patients with this subtype of AML.

Transcriptional regulation of the cystathionine-beta -synthase gene in Down syndrome and non-Down syndrome megakaryocytic leukemia cell lines

Children with Down syndrome (DS) with acute myeloid leukemia (AML) have significantly higher event-free survival rates compared to those with non-DS AML, linked to greater cytosine arabinoside (ara-C) sensitivity and higher transcript levels of the chromosome 21-localized gene, cystathionine-beta-synthase (CBS), in DS myeloblasts. In this study, we examined the transcriptional regulation of the CBS gene in the DS megakaryocytic leukemia (AMkL) cell line, CMK, characterized by significantly higher CBS transcripts compared with the non-DS AMkL cell line, CMS. Rapid amplification of 5'-cDNA ends (5'-RACE) analysis demonstrated exclusive use of the CBS -1b promoter in the cell lines, and transient transfections with the full-length CBS -1b luciferase reporter gene construct showed 40-fold greater promoter activity in the CMK than CMS cells. Electrophoretic mobility shift assays showed enhanced binding of the transcription factors Sp1/Sp3 to 2 GC/GT-box elements (GC-f and GT-d) in the upstream regions of the CBS -1b promoter in CMK nuclear extracts and undetectable binding in CMS cells. Mutation of the GC-f- or GT-d-binding site resulted in an approximately 90% decrease of the CBS -1b promoter activity in transient transfections of CMK cells. Chromatin immunoprecipitation assays confirmed in vivo binding of Sp3, USF-1, and nuclear factor YA (NF-YA) to the CBS -1b promoter region in chromatin extracts of CMK and CMS cells. Decreased binding of Sp1/Sp3 in CMK nuclear extracts following treatment with calf alkaline phosphatase suggested a role for phosphorylation of Sp1/Sp3 in regulating CBS promoter activity and in the differential CBS expression between CMK and CMS cells. The results of this study with clinically relevant cell line models suggest potential mechanisms for disparate patterns of CBS gene expression in DS and non-DS myeloblasts and may, in part, explain the greater sensitivity to chemotherapy shown by patients with DS AML.

Acute megakaryoblastic leukaemia: a national clinical and biological study of 53 adult and childhood cases by the Groupe Français d'Hématologie Cellulaire (GFHC)

Since the WHO classification of haematological malignancies recommended the description of global entities, we performed a national M7-AML study to correlate morphological, immunological and cytogenetic features, and to find new clinically relevant M7 entities. This study is based on accurate morphological and immunological study to select pure megakaryoblastic proliferations and to eliminate megakaryocytic participation in haemopathies. We collected 53 cases: 23 adults and 30 children. We confirm the wide heterogeneity of adult M7. In adults, the cytogenetic abnormalities are frequently those of secondary leukaemia while a few patients have a previous history and morphological features of dyshaematopoiesis; their outcome is very poor. Among children, besides the well-known Down syndrome M7, we in particular, studied ten t(1;22) M7 and one OTT-MAL transcript positive case with normal karyotype presenting specific features. We were already aware of their younger age, female and tumoral presentation, but we also found a lower percentage of bone marrow blasts, sometimes without any megakaryoblastic bone marrow involvement, but always, with a dysmegakaryocytopoiesis associated with micromegakaryocytes. They are generally good responders to intensive AML chemotherapy with very long disease-free survivals (DFS). Accordingly, OTT-MAL transcript study, in infant M7 with normal karyotype, is recommended and we feel that this entity should be added to the WHO AML classification.

Voriconazole in the management of invasive aspergillosis in two patients with acute myeloid leukemia undergoing stem cell transplantation

The management of invasive aspergillosis in patients with hematological malignancies remains controversial. A major problem is how to manage patients who had invasive aspergillosis during remission induction and consolidation therapy and then undergo SCT. Indeed in these patients the mortality rate related to invasive aspergillosis recurrence remains unacceptably high. We report two cases of patients who underwent remission induction for AML, developed invasive aspergillosis during antifungal prophylaxis with itraconazole, failed amphotericin B deoxycholate and liposomal amphotericin B treatment, were successfully treated with voriconazole and eventually underwent SCT with voriconazole prophylaxis without reactivation of invasive aspergillosis.

Filgrastim treatment of acute myelogenous leukemia (M7) relapse after allogeneic peripheral stem cell transplantation resulting in both graft-versus-leukemia effect with cytogenetic remission and chronic graft-versus-host disease manifesting as polyserositis and subsequent bronchiolitis obliterans with organizing pneumonia

Filgrastim (granulocyte colony-stimulating factor) has recently been reported to successfully treat patients with leukemic relapse after allogeneic peripheral stem cell transplantation (PSCT). However, the majority of the patients who responded also developed graft-versus-host disease (GVHD). Polyserositis as a manifestation of GVHD is a rare phenomenon. We report the first case of polyserositis following the use of filgrastim to treat a patient with acute myelogenous leukemia (M7), who had relapsed after an initially successful allogeneic PSCT. The polyserositis manifested with effusions and was initially controlled with high doses of steroids and pericardial stripping; however, after a quiescent period the patient eventually developed bronchiolitis obliterans with organizing pneumonia that required additional immunosuppressive therapy. We review the literature on GVHD-associated polyserositis and offer potential explanations for its pathogenesis.

Megakaryoblastic transformation of polycythemia vera with hypercalcemia

Polycythemia vera (PV) is known to occasionally transform into acute leukemia. Administration of alkylating agents seems to be associated with an increased risk of leukemic transformation of PV. Hypercalcemia is a serious complication of malignancies, but it is uncommon in acute leukemia. In the majority of malignancies with hypercalcemia, elevated parathyroid hormone-related protein (PTHrP) is thought to be the main cause of hypercalcemia. We report a rare case of megakaryoblastic transformation of PV with hypercalcemia. A 62-year-old man was diagnosed as having PV in 1983, and he had received ranimustine and busulfan. He developed acute megakaryoblastic leukemia 17 years after the initial diagnosis of PV. Serum calcium was elevated, the serum level of intact parathyroid hormone (PTH) was suppressed, and the level of intact PTHrP was slightly elevated. He had no lytic bone lesions; however, uncoupling of bone turnover due to an increase in bone resorption and a decrease in bone formation was detected by using biochemical markers. Since the level of PTHrP was slightly elevated from the normal value, we speculated that PTHrP produced in the local field by leukemic cells might have been more abundant than circulating PTHrP. Pamidronate and adrenocortical hormone were effective in reducing the serum calcium level. However, the patient died shortly after the start of induction chemotherapy. The prognosis of cases of PV that has transformed into acute leukemia is generally poor because the majority of such cases are refractory to chemotherapy.

Telomerase and the benign and malignant megakaryoblastic leukemias of Down syndrome

The most common form of leukemia in Down syndrome patients is megakaryoblastic leukemia. There are two forms of the disease. Transient leukemia (TL) is a form of megakaryoblastic leukemia that occurs in newborns with Down syndrome and usually disappears spontaneously within the first 3 months of life. Acute megakaryoblastic leukemia (AMKL) occurs in Down syndrome children within the first 4 years of life and is fatal without treatment. The megakaryoblasts of TL and AMKL are indistinguishable by light and electron microscopy; yet, TL is benign and AMKL is malignant. One of the hallmarks of many malignancies is the expression of telomerase. It is therefore hypothesized that the transient, benign form of megakaryoblastic leukemia (TL) would not contain telomerase activity, whereas telomerase would be demonstrable in the malignant form of the disease. Telomerase activity was determined in the blood and/or bone marrow aspirates in 29 cases of AMKL and 34 cases of TL. The authors found telomerase activity in 15 of 29 (52%) cases, of AMKL and in only 4 of 34 (12%) cases of TL (P < 0.001). Furthermore, three of the four telomerase-positive TL cases were particularly severe, of which two were fatal. Telomerase activity is found frequently in the leukemic cells of the malignant form of megakaryoblastic leukemia but rarely in the benign form of the disease (TL). Observations provide evidence that telomerase may be a critical factor for the malignant conversion of leukemic cells.

Distinctive multidrug sensitivity and outcome of acute erythroblastic and megakaryoblastic leukemia in children with Down syndrome

We assessed the in vitro chemosensitivity of acute erythroblastic and megakaryoblastic leukemia cells from children with Down syndrome (DS) compared to non-DS children. We conducted in vitro tests using the MTT assay of bone marrow samples from 12 children with DS and 16 children without DS. Patients were newly diagnosed based on the morphology and expression of platelet-specific antigens. Induction failure occurred more frequently in the non-DS group (n = 4) than in the DS group (n = 0, P = .053). Children with DS had a superior event-free survival (EFS) probability of 0.750 at 4 years, compared to an EFS probability of 0.375 for non-DS children (P = .049). Blast cells from DS patients were significantly more sensitive to daunorubicin, melphalan, mitoxantrone, 4-hydroperoxy-cyclophosphamide, vincristine, etoposide, bleomycin, and pirarubicin than those from non-DS patients. Four of the 16 non-DS patients were found to have acquired an extra chromosome 21 in their leukemia cells: blasts from these patients also tended to have greater chemosensitivity than those from patients without an extra chromosome 21. Blast cells from DS patients are markedly sensitive to various drugs. These results suggest that the fragility of blast cells derived from DS patients may be related to an increased susceptibility to apoptosis.

Identification and molecular characterisation of a CALM-AF10 fusion in acute megakaryoblastic leukaemia

The t(10;11)(p13;q14-21) is a non-random translocation described in acute lymphoblastic and myeloid leukaemias. It results in the fusion of the gene CALM, which encodes a clathrin assembly protein, on 11q14 to the gene AF10, a putative transcription factor on 10p13. Here we describe for the first time, the occurrence of a CALM-AF10 fusion in a case of acute megakaryoblastic leukaemia. Fluorescence in situ hybridisation and reverse transcriptase polymerase chain reaction were used to confirm the presence of a CALM-AF10 fusion. A novel splice variant of CALM missing nt 1927-2091 was also detected. Though CALM is a cytoplasmic protein, the chimaeric fusion product is able to localise to both the nucleus and cytoplasm. Analysis of the fusion variants suggests, however, that the critical fusion product is likely to be cytoplasmic and contain the interactive leucine zipper of AF10.

A t(1;22)(p13;q13) in four children with acute megakaryoblastic leukemia (M7), two with Down syndrome

We report four children with acute megakaryoblastic leukemia (AML-M7) and t(1;22)(p13;q13), two of them with Down syndrome; their ages were 7 months, and 6, 7, and 10 years. These findings differ from those reported in children with M7 and t(1;22) at the age of presentation (exclusively under 1-year-old) and in the two cases associated with Down syndrome (t[1;22],+21c) that may be due to the high heterogeneity of the chromosomal changes in children with AML. We cannot disregard ethnic difference distribution of chromosomal changes and age of presentation in Mexican children with AML.

Acute megakaryoblastic leukemia in Down syndrome: orbital infiltration

PURPOSE

To describe an uncommon ocular presentation of acute megakaryoblastic leukemia in a child with Down syndrome.

METHOD

Case report. Initial manifestation of disease was bilateral proptosis with secondary exposure keratitis caused by leukemic infiltration of the orbits.

RESULTS

Bone marrow biopsy and immunophenotyping established the diagnosis of acute megakaryoblastic leukemia (FAB-M7). The leukemia was treated successfully with chemotherapy, with resolution of proptosis. The patient remained in remission more than 1 year after cessation of treatment.

CONCLUSIONS

Bilateral proptosis can be a presenting sign of acute megakaryoblastic leukemia, a malignancy associated with Down syndrome.