[Successful second allogeneic hematopoietic stem cell transplantation with azacitidine as bridging therapy for relapsed juvenile myelomonocytic leukemia]

Hematopoietic cell transplantation (HCT) is the only curative therapy for juvenile myelomonocytic leukemia (JMML). Meanwhile, an established conventional chemotherapy before HCT remains unavailable. Studies have shown that azacitidine (AZA), which is a DNA methyltransferase inhibitor, is clinically effective for JMML as a bridging therapy for HCT; a prospective clinical trial in Japan is ongoing. Herein, we present a case of a patient with JMML who was administered AZA as bridging therapy for both first and second HCT. A 3-year-old boy with neurofibromatosis type 1 was administered with intravenous AZA (75 mg/m²/day for 7 days, intervals of 28 days, and four cycles) and received myeloablative HCT (unrelated bone marrow). When relapse occurred on day 123, four additional AZA therapy cycles were administered, and the patient received a second nonmyeloablative HCT (cord blood). After seven AZA therapy cycles as post HCT consolidation, hematological remission was sustained for 16 months after the second HCT. No severe adverse events occurred. AZA is effective for JMML as a bridging therapy for HCT and has robust cytoreductive potential despite the risk of relapse.

Single-Arm Non-Blinded Multicenter Clinical Trial on T-Cell-Replete Haploidentical Stem Cell Transplantation Using Low-Dose Antithymocyte Globulin for Relapsed and Refractory Pediatric Acute Leukemia

Although approximately 70% of pediatric hematological malignancies are curable, approximately 30% remain fatal. No standard treatment is available in patients showing relapse and those with refractory disease. Although different methods are adopted in different hospitals, its efficacy is extremely limited. In recent years, haploidentical stem cell transplantation, involving high-dose cyclophosphamide administration post-transplanta tion, has been used, mainly in adults; however, its application is limited to removal of alloreactive T cells. Multicenter single-arm clinical trials of T-cell replete haploidentical stem cell transplantation (TCR-haplo-SCT) will be conducted in children with relapsed and refractory acute leukemia. After myeloablative conditioning using total body irradiation or busulfan, intensive graft versus host disease prophylaxis is administered, consisting of low-dose rabbit anti-human thymocyte globulin, tacrolimus, methotrexate, and prednisolone. An external control group is set up for the study. The treatment period is around 3 months, and the follow-up period is 2 years from transplantation completion.The aim of this study is to verify the efficacy and safety of TCR-haplo-SCT and present it as a new immune cell therapy for improving survival rate in children with relapsed and refractory acute leukemia.

Clinical features of children with polycythemia vera, essential thrombocythemia, and primary myelofibrosis in Japan: A retrospective nationwide survey

Background

Philadelphia-negative (Ph-negative) myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are exceptionally rare during childhood. Thus, clinical features of pediatric Ph-negative MPNs remain largely unknown. This study was therefore performed to address this.

Methods

We performed a retrospective study to collect clinical information of children diagnosed with Ph-negative MPNs from 2000 to 2016 using questionnaires in qualified institutions in Japan. The results obtained from the questionnaire survey were then combined with those from the national registry data.

Results

Among 50 children identified, five had PV, 44 had ET, and one had PMF. Median age at diagnosis was 14.0, 9.0, and 0 years, respectively. Male to female ratio was 4:1, 21:23, and 1:0, respectively. Detection rates of the JAK2 V617F variant were 0/5 in PV and 9/39 in ET. Frequencies of complications, such as thrombosis and subsequent leukemia, were lower than complication frequencies in adults. We identified two children who developed subsequent leukemia, which has not been reported previously, and one of them died.

Conclusion

This is the first nationally representative survey of pediatric Ph-negative MPNs. Given its rarity, an international collaboration with comprehensive genetic analyses might be needed to fully elucidate the clinical and genetic features.

Retrospective analysis of children with high-risk acute myeloid leukemia who underwent allogeneic hematopoietic stem cell transplantation following complete remission with initial induction chemotherapy in the AML-05 clinical trial

In the AML-05 clinical trial conducted by the Japanese Pediatric Leukemia/Lymphoma Group from 2006 to 2010, children with high-risk acute myeloid leukemia (HR AML) received allogeneic hematopoietic stem cell transplantation (allo-HSCT) at first complete remission (CR1). The aim of this study was to investigate the impact of allo-HSCT on the outcome of HR AML. Patients with either monosomy 7, 5q-, t(16;21), Ph1, FLT3-ITD, or induction failure after the first course of chemotherapy were eligible for transplant. Of 53 children with HR AML, 51 received allo-HSCT-45 in CR1, five in CR2, and one with non-CR. t(8;21), t(9;11), and t(16;21) abnormalities were identified in eight, five, and four patients, respectively. The stem cell sources varied-bone marrow in 30 patients, peripheral blood in three, and cord blood in 18. The median follow-up was 62 months. The overall survival (OS) rates at 3 years were 73% and 25% for patients who received transplant at CR1 and ≥CR2, respectively. Multivariable analysis showed that patients with chronic graft-versus-host disease (cGVHD) had better OS. This study supports that allo-HSCT is a suitable treatment for HR AML in CR1. The favorable outcome associated with cGVHD indicates that a graft-versus-leukemia effect might be occurring.

Extracellular signal-regulated kinase activation of self-healing Langerhans cell histiocytosis: A case report

A 3-month-old boy developed small papules on his trunk. After the papules increased in number, the patient was diagnosed with Langerhans cell histiocytosis based on the pathological findings. He was referred to our department for further examination. Upon initial examination, the papules and nodules were scattered on his back, abdomen and lumbar region. Because he did not present with any organ involvement except the skin, he was diagnosed with single-system and skin-limited Langerhans cell histiocytosis. Skin rashes were treated with a topical steroid and started regressing 3 months after onset. All papules disappeared 6 months after onset. In this boy, the Langerhans cell histiocytosis tumor cells expressed phosphorylated extracellular signal-regulated kinases. In Langerhans cell histiocytosis, BRAF V600E and other genes are known to mutate to act as driver mutations in stem cells of the myeloid dendritic cell lineage. Consequently, extracellular signal-regulated kinases are continuously activated, which contributes to Langerhans cell histiocytosis carcinogenesis.

Possible involvement of IL-6-producing tissue-resident macrophages in early-onset pericardial effusion pathogenesis after hematopoietic stem cell transplantation

PURPOSE

Pericardial effusion (PE) is a potentially life-threatening complication following hematopoietic stem cell transplantation (HCT). A higher incidence of early-onset PE, unrelated to graft-versus-host disease, before day 100 after HCT has been reported in pediatric patients, but the pathogenic mechanism is poorly understood. Aiming to determine the pathogenesis of early-onset PE in pediatric patients, we analyzed the cytokine concentration and cell population in the pericardial fluid of four pediatric patients with PE.

METHODS

Between January 2009 and December 2015, four patients requiring pericardiocentesis for clinically significant PE were identified in 60 patients. We evaluated the interleukin-6 (IL-6), interferon-γ, IL-1β, and tumor necrosis factor-α levels in PE. Two patients were available for analysis with intracellular cytokine flow cytometry and a chimerism assay.

RESULTS

All patients showed the accumulation of pericardial macrophages and high concentrations of IL-6 in PE. Notably, the accumulated pericardial macrophages were CD163⁺ CD15⁺ CD14⁺ cells of host origin that produced IL-6.

CONCLUSION

These IL-6-producing tissue-resident macrophages may be key players in the pathogenesis of early-onset PE.

Constitutional abnormalities of IDH1 combined with secondary mutations predispose a patient with Maffucci syndrome to acute lymphoblastic leukemia

Maffucci syndrome is a nonhereditary disorder caused by somatic mosaic isocitrate dehydrogenase 1 or 2 (IDH1 or IDH2) mutations and is characterized by multiple enchondromas along with hemangiomas. Malignant transformation of enchondromas to chondrosarcomas and secondary neoplasms, such as brain tumors or acute myeloid leukemia, are serious complications. A 15-year-old female with Maffucci syndrome developed B-cell precursor acute lymphoblastic leukemia (BCP-ALL). A somatic mutation in IDH1 was detected in hemangioma and leukemic cells. KRAS mutation and deletion of IKZF1 were detected in leukemic cells. Patients with Maffucci syndrome may, therefore, be at risk of BCP-ALL associated with secondary genetic events that affect lymphocyte differentiation.

Comparison of second transplantation and donor lymphocyte infusion for donor mixed chimerism after allogeneic stem cell transplantation for nonmalignant diseases

BACKGROUND

Donor mixed chimerism (MC) is an increasing problem after hematopoietic stem cell transplantation (HSCT) for nonmalignant diseases.

PROCEDURE

In this study, a self-administered questionnaire was used to retrospectively compare efficacy and safety in 49 patients undergoing second HSCT (n = 13) or donor lymphocyte infusion (DLI; n = 36) as treatment for MC.

RESULTS

The response rate to DLI of patients with secondary graft failure (GF) (25.0%) was significantly lower than that of patients without secondary GF (81.3%; P = 0.041). Among patients undergoing DLI, the rates of successful response were significantly higher in patients having at least 30% donor chimerism (94.1%) than in patients having less than 30% donor chimerism (61.1%; P = 0.041). Furthermore, the rates of successful response were significantly higher in patients receiving larger first or maximum doses of DLI. Sixteen (50.0%) of 32 patients without secondary GF attained complete chimerism after DLI. The cumulative incidence of grade II-IV acute graft-versus-host disease and cytopenia was 37.6 and 26.1%, respectively.

CONCLUSIONS

DLI yields promising response rates in most patients with higher donor chimerism levels, whereas second HSCT is more likely to benefit patients with lower donor chimerism levels.

Invasive Bacterial Infection in Patients with Interleukin-1 Receptor-associated Kinase 4 Deficiency: Case Report

Interleukin-1 receptor-associated kinase 4 (IRAK4) deficiency (OMIM #607676) is a rare primary immunodeficiency of innate immune defect. We identified 10 patients from 6 families with IRAK4 deficiency in Japan, and analyzed the clinical characteristics of this disease. Nine patients had homozygous c.123_124insA mutation, and 1 patient had c.123_124insA and another nonsense mutation (547C>T). Umbilical cord separation occurred on the 14th day after birth or thereafter. Two patients had no severe infections owing to the prophylactic antibiotic treatment. Severe invasive bacterial infections occurred before the age of 3 in the other 8 patients. Among them, 7 patients had pneumococcal meningitis. Five patients died of invasive bacterial infection during infancy, although intravenous antibiotic treatment was started within 24 hours after onset in 4 patients among them. Analysis of cerebrospinal fluid of the patients who had fatal meningitis revealed very low glucose levels with only mild pleocytosis. The clinical courses of invasive bacterial infections were often rapidly progressive despite the early, appropriate antibiotic treatment in IRAK4 deficiency patients. The early diagnosis and appropriate prophylaxis of invasive bacterial infections are necessary for the patients.

Germline mutation of CBL is associated with moyamoya disease in a child with juvenile myelomonocytic leukemia and Noonan syndrome-like disorder

Germline mutations in CBL have been identified in patients with Noonan syndrome-like phenotypes, while juvenile myelomonocytic leukemia (JMML) harbors duplication of a germline CBL, resulting in acquired isodisomy. The association between moyamoya disease and Noonan syndrome carrying a PTPN11 mutation has recently been reported. We present a patient with JMML who developed moyamoya disease and neovascular glaucoma. Our patient exhibited a Noonan syndrome-like phenotype. Genetic analysis revealed acquired isodisomy and a germline heterozygous mutation in CBL. This is a rare case of CBL mutation associated with moyamoya disease. Prolonged RAS pathway signaling may cause disruption of cerebrovascular development.

Comparison of continuous and twice-daily infusions of cyclosporine A for graft-versus-host-disease prophylaxis in pediatric hematopoietic stem cell transplantation

BACKGROUND

Cyclosporine A (CsA) is used widely for graft-versus-host disease (GVHD) prophylaxis in hematopoietic stem cell transplantation (HSCT); however, the optimal schedule of its administration has not been established. Although comparative studies of adult patients undergoing HSCT have demonstrated enhanced efficacy and safety of twice-daily infusion (TD) compared with continuous infusion (CIF) of CsA, to our knowledge, similar studies have not yet been performed in pediatric groups.

PROCEDURE

A self-administered questionnaire was used to retrospectively compare the clinical outcome and incidence of CsA-associated adverse events of 70 pediatric acute myelogenous leukemia patients who were receiving CsA by TD (n = 36) or CIF (n = 34) as GVHD prophylaxis for their first allogeneic HSCT.

RESULTS

The cumulative incidences of grade II-IV acute GVHD and chronic GVHD, as well as the overall survival and event-free survival rates, did not differ significantly between the TD and CIF groups; however, the incidence of severe hypertension was significantly higher in the CIF group than the TD group.

CONCLUSIONS

The analysis presented here indicates that TD and CIF administration of CsA have similar prophylactic effect on pediatric GVHD and suggest that TD is associated with a lower rate of toxicity than CIF in pediatric patients undergoing HSCT. Pediatr Blood Cancer 2015;62:291-298. © 2014 Wiley Periodicals, Inc.

A rare case of septic pulmonary embolism caused by infection-associated catheter removal in a patient with Hodgkin's lymphoma

As a reflection of the considerable increase in the number of cancer patients treated with chemotherapy, indications for the use of implanted venous catheters are rapidly growing. However, in some cases, implanted venous catheters induce unwelcome complications. We herein report a rare case of septic pulmonary embolism (SPE) caused by local infection-associated catheter removal during the administration of ABVd combination chemotherapy consisting of adriamycin, bleomycin, vinblastine and dacarbazine in a patient with Hodgkin's lymphoma of the mixed cellularity type. During the course of treatment with chemotherapy administered via implanted venous catheters, think it is crucial to monitor for the potential occurrence of SPE.

Simple diagnosis of STAT1 gain-of-function alleles in patients with chronic mucocutaneous candidiasis

CMCD is a rare congenital disorder characterized by persistent or recurrent skin, nail, and mucosal membrane infections caused by Candida albicans. Heterozygous GOF STAT1 mutations have been shown to confer AD CMCD as a result of impaired dephosphorylation of STAT1. We aimed to identify and characterize STAT1 mutations in CMCD patients and to develop a simple diagnostic assay of CMCD. Genetic analysis of STAT1 was performed in patients and their relatives. The mutations identified were characterized by immunoblot and reporter assay using transient gene expression experiments. Patients' leukocytes are investigated by flow cytometry and immunoblot. Six GOF mutations were identified, three of which are reported for the first time, that affect the CCD and DBD of STAT1 in two sporadic and four multiplex cases in 10 CMCD patients from Japan. Two of the 10 patients presented with clinical symptoms atypical to CMCD, including other fungal and viral infections, and three patients developed bronchiectasis. Immunoblot analyses of patients' leukocytes showed abnormally high levels of pSTAT1 following IFN-γ stimulation. Based on this finding, we performed a flow cytometry-based functional analysis of STAT1 GOF alleles using IFN-γ stimulation and the tyrosine kinase inhibitor, staurosporine. The higher levels of pSTAT1 observed in primary CD14(+) cells from patients compared with control cells persisted and were amplified by the presence of staurosporine. We developed a flow cytometry-based STAT1 functional screening method that would greatly facilitate the diagnosis of CMCD patients with GOF STAT1 mutations.

Assessment of late cardiotoxicity of pirarubicin (THP) in children with acute lymphoblastic leukemia

BACKGROUND

Pirarubicin (tetrahydropyranyl-adriamycin: THP) is a derivative of doxorubicin with reportedly less cardiotoxicity in adults. However no studies of cardiotoxicity in children treated with THP have been reported. This study was performed to assess the THP-induced cardiotoxicity for children with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

This study comprised 61 asymptomatic patients aged from 7.6 to 25.7 years old. Median follow-up time after completion of anthracycline treatment was 8.1 years (range: 1.7-12.5). The cumulative dose of THP ranged from 120 to 740 mg/m(2) with a median of 180 mg/m(2) . Patients underwent electrocardiogram (ECG), echocardiography, the 6-min walk test (6MWT), and measurements of serum brain natriuretic peptide (BNP) before and after exercise.

RESULTS

All subjects showed normal left ventricular function assessed by echocardiography. Ventricular premature contraction in Holter ECG and reduced exercise tolerance in the 6MWT were detected in 2/46 (3.3%) and 5/41(12.2%), respectively. Abnormal BNP levels were detected in 6/60 (10%) both before and after exercise. The cumulative dose of THP was significantly correlated with BNP levels after exercise (r = 0.27, P = 0.03), but not with any other cardiac measurements. Further analysis revealed that subjects with a high cumulative dose ≧300 mg/m(2) had significantly higher BNP levels after exercise compared with subjects with a low cumulative dose <300 mg/m(2) (P = 0.04).

CONCLUSIONS

No significant cardiac dysfunction was detected in long-term survivors who received THP treatment. The use of post-exercise BNP level to indicate high cardiotoxicity risk should be verified by further study.

Minimal residual disease-based augmented therapy in childhood acute lymphoblastic leukemia: a report from the Japanese Childhood Cancer and Leukemia Study Group

BACKGROUND

The majority of minimal residual disease (MRD)-positive patients with acute lymphoblastic leukemia (ALL) have poor outcomes. The ALL2000 study was performed to evaluate the efficacy of augmented chemotherapy based on MRD-restratification in childhood ALL.

PROCEDURE

Between 2000 and 2004, 305 eligible patients with precursor B or T-cell ALL were enrolled in the ALL2000 study. The ALL941-based therapy protocol utilized PCR MRD assays using Immunoglobulin and T-cell receptor gene rearrangements. They were initially stratified into three risk-groups according to leukocyte count and age, and MRD levels were measured at weeks 5 (TP1) and 12 (TP2) for a second stratification. From week 14, patients with MRD levels ≥ 10(-3) received an increase in therapy (one risk group higher), while the remainder continued to receive the initial risk-adapted therapy.

RESULTS

The overall 5-year event-free survival (EFS) rate for ALL2000 was 79.7 ± 2.4%. MRD stratification was feasible for 234 of 301 patients (77%) who achieved complete remission. The EFS rate of the MRD stratifiable (MRD) group was 82.5 ± 2.6%, considerably superior to the 74.7 ± 5.7% of MRD non-stratifiable (Non-MRD) group (P = 0.084) and the 74.4 ± 2.1% for ALL 941 (P = 0.012). MRD-positive patients at TP2 showed inferior outcomes as compared with MRD-negative cases, but the difference did not reach a statistically significant level in any risk groups or immunophenotypes.

CONCLUSIONS

These results suggest that augmented therapy for MRD-positive patients at TP2 contributed to better outcomes of the ALL2000 study.

Childhood blastic NK cell leukemia successfully treated with L-asparagenase and allogeneic bone marrow transplantation

Blastic NK cell lymphoma/leukemia is a rare and highly malignant neoplasia in both adults and children. It is characterized by lymphoblastoid morphology without cytoplasmic granules and immature NK cell immunophenotypes (CD56+, CD57-, CD16-). It has predilection for extranodal organ involvement, and the prognosis of affected patients is extremely poor under the current chemotherapy. We present a 14-year-old girl who was diagnosed as having blastic NK cell leukemia with mediastinal, pleural, and pericardial involvement. Immunophenotyping of her leukemic cells showed positive for CD2, CD5, CD7, CD34, CD56, HLA-DR, and cytoplasmic CD3. T cell receptor (TCR) and Immunoglobulin heavy chain genes were not rearranged. She received chemotherapy for acute lymphoblastic leukemia incorporating L-asparaginase (L-asp) which successfully induced complete remission. Bone marrow transplantation (BMT) from her HLA-identical sibling was conducted after two courses of consolidation therapy. Expression of aspargine synthetase (AS) protein in the leukemic cells at diagnosis was examined by an immunocytochemical method. She remains in hematological remission for over 36 months after BMT. The expression of AS protein was negative, suggesting that the leukemic cells were sensitive to L-asp. Induction and consolidation therapy incorporating L-asp followed by allo-BMT might be a promising treatment for child hood blastic NK cell leukemia, but more samples of the rare leukemia need to be studied before any definitive conclusions can be drawn.

Two newly identified genomic mutations in a Japanese female patient with fructose-1,6-bisphosphatase (FBPase) deficiency

Fructose-1,6-bisphosphatase (FBPase) (EC 3.1.3.11) catalyzes the splitting of fructose-1,6-bisphosphate into fructose 6-phosphate and inorganic phosphate. FBPase deficiency is an autosomal recessive inherited disorder caused by distraction of the fructose-1,6-bisphosphatase 1 gene (FBP1) and features severely impaired gluconeogenesis. We studied a female patient with typical FBPase deficiency symptoms. The FBPase activity of her peripheral white blood cells was undetectable. Genetic analyses of FBP1 revealed her to be a compound-heterozygote of two new mutations F194S and P284R. Gene tracking in the family revealed the mother to be a heterozygote of F194S, and the father and a sister to be heterozygotes of P284R. As both Phe194 and Pro284 of FBPase are highly conserved in many species and close to crucial amino acid residues to FBPase functions, these mutations could be responsible for the loss of FBPase activities.

Low natural killer activity and central nervous system disease as a high-risk prognostic indicator in young patients with hemophagocytic lymphohistiocytosis

BACKGROUND

Familial hemophagocytic lymphohistiocytosis HLH (FHL) is fatal, unless patients are rescued with hematopoietic stem cell transplantation (SCT). Although the molecular identification of FHL now is possible at least in part from perforin gene study, many cases escape detection or never are tested due to the lack of specific hallmarks, making diagnosis difficult. To the authors' knowledge, it remains to be determined whether persistently low natural killer cell (NK) activity and a high incidence of central nervous system (CNS) disease increase the probability of FHL.

METHODS

The authors analyzed 42 HLH patients age < 2 years, 13 of whom developed overt CNS disease and 5 of whom demonstrated persistently deficient NK activity (Group 1). The remaining 24 patients had no CNS disease and had NK activity of moderate decrease to within the normal range (Group 2).

RESULTS

In Group 1, CNS symptoms were detected in 6 cases within 1 month and between 4.5-9 months in 6 other patients. In these cases, spotty lesions demonstrating a high T2 signal in the white matter were noted on brain magnetic resonance imaging. The survival was significantly poor for patients in Group 1 unless they were rescued with SCT, which was performed in 5 of the 13 patients with CNS disease and in all 5 patients with persistent NK activity deficiency. SCT was successful in 9 patients, with no CNS sequelae reported after the transplantation. Conversely, the prognosis of the 24 patients in Group 2 was better and only 1 patient required SCT.

CONCLUSIONS

Very young HLH patients (age < 2 years) who are at high risk of fatal FHL with persistently deficient NK activity and/or overt CNS disease require appropriate SCT to reverse CNS disease and achieve a complete cure.

Minimal residual disease in early phase of chemotherapy reflects poor outcome in children with acute lymphoblastic leukemia--a retrospective study by the Children's Cancer and Leukemia Study Group in Japan

We analyzed the minimal residual disease (MRD) in 50 children with acute lymphoblastic leukemia (ALL) by amplifying the clonally rearranged T-cell receptor (TCR) gamma/delta chain and/or immunoglobulin (Ig) kappa chain gene using the allele-specific-PCR method. All children were treated according to the protocols of the Children's Cancer and Leukemia Study Group of Japan (CCLSG). The patients were stratified into four risk-groups according to the leukocyte count and age at diagnosis. We prospectively sampled the patients' bone marrow at 1 month (point 1) and 3 months (point 2) after the initiation of chemotherapy and quantitated the MRD retrospectively. The results of MRD were closely related with the clinical outcome. The relapse rate of the patients MRD-positive at points 1 and 2 was 46% (6/13) and 86% (6/7), respectively, whereas those MRD-negative results at point 1 and 2 were 13% (3/13) and 3% (3/30), respectively. We found significant differences in the event-free survival between MRD-positive children and MRD-negative children like the reports, which have been made by BFM and EORTC groups. We conclude that MRD in an early phase of chemotherapy can be a good predictor of the prognosis of childhood ALL regardless of the protocol of chemotherapy or race.

Prognostic impact of CD45 antigen expression in high-risk, childhood B-cell precursor acute lymphoblastic leukemia

To evaluate the clinical implications of CD45 expression in acute childhood lymphoblastic leukemia (ALL), we measured the CD45 expression of blast cells from 133 untreated patients with childhood B-precursor ALL (n = 118) or T-ALL (n = 15). CD45 expression (> or = 20%) was detected in all 15 cases (100%) of T-ALL, and 101 cases (86%) of B-precursor ALL. In 122 cases, the fluorescence intensity of the CD45 expression was measured as a relative value; the ratio of average linear values (RALV) of CD45 on the blasts to that on CD3-positive T-lymphocytes from the same specimen. The expression was more intense in the T-ALL cases than in the B-precursor ALL cases (RALV, mean +/- SE: T-ALL 0.230 +/- 0.04 vs. pro-B ALL 0.150 +/- 0.012/pre-B ALL 0.153 +/- 0.019, p < 0.05). However, the intensity of the CD10, CD19, CD20 and CD34 antigen immunoreactivity did not correlate with the CD45 expression. Patients with hyperdiploidy (chromosome number > 50) showed significantly lower levels of CD45 expression than patients with t(1;19) or normal karyotypes (RALV, mean +/- SE: 0.081 +/- 0.022 vs. 0.133 +/- 0.03/0.143 +/- 0.019, p < 0.05). Other clinical features such as age, gender and WBC count did not correlate with CD45 expression. The prognostic implications of CD45 expression were studied in non-high-risk (low-risk + intermediate-risk) (n = 60) and high-risk patients (n = 52) with B-precursor ALL who had been treated with the risk-directed protocol of ALL-941 trial. Although CD45 expression did not correlate with the event-free survival (EFS) of the non-high-risk patients, there was a significant correlation between the expression levels and the EFS of the high-risk patients: the 3-year EFS rate of the CD45low group (n = 26, RALV = 0.017-0.132) was 88 +/- 7% versus the CD45high group (n = 26, RALV = 0.133-0.450) at 34 +/- 24% (p < 0.05). These results show that the levels of expression of the CD45 antigen on leukemic lymphoblasts are significantly correlated with the clinical features and prognosis of childhood ALL.

[Prognostic significance of chromosome analysis in childhood acute lymphoblastic leukemia. Children's Cancer and Leukemia Study Group (CCLSG)]

We analyzed the prognostic significance of chromosomal findings in children with acute lymphoblastic leukemia (ALL), treated according to the Children's Cancer and Leukemia Study Group protocols between 1987 and 1993. Patients were classified into 5 groups according to chromosome number. The patients with a hyperdiploid(> 50) karyotype(13%) had the best prognosis [4-year event-free survival (EFS): 83 +/- 6%], while those with a pseudodiploid karyotype (24%) had the worst prognosis(4-year EFS: 52 +/- 6%) (log-rank, p = 0.03). However, multivariate analysis revealed that the ploidy classification had no prognostic significance in terms of EFS. When patients were classified according to chromosome abnormalities, those with any type of translocation had a worse outcome (4-year EFS: 33 +/- 9%) than those with hyperdiploidy(> 50), normal diploidy, and other abnormalities(log-rank, p < 0.0001). Multivariate analysis revealed that chromosome abnormalities were an independent prognostic factor (relative risk 3.98; p < 0.0001). Patients with t(1; 19) had an EFS similar to that of patients with chromosome abnormalities other than translocations or normal diploidy. We conclude that chromosomal findings have prognostic significance, although some chromosome abnormalities lost their statistical significance after modern intensified chemotherapy. Childhood ALL should be further stratified according to chromosome classification.

Internal tandem duplication of the FLT3 gene and clinical evaluation in childhood acute myeloid leukemia. The Children's Cancer and Leukemia Study Group, Japan

We analyzed tandem duplication in the juxtamembrane (JM) domain of the FLT3 (FMS-like tyrosine kinase 3/FLK2, CD135) gene in 94 children with acute myeloid leukemia (AML) and evaluated its correlation with clinical features. Longer polymerase chain reaction (PCR) products were observed in five patients; 1/3 of M0, 119 of M1, 1/39 of M2, 1/9 of M3 and 1/12 of M5. The sequence analyses of abnormal PCR products showed that all the abnormal products were derived from tandem duplications involving the JM domain and that all the lengthened sequences were in-frame as we previously reported. Statistical analyses revealed a significantly lower incidence of the tandem duplication in childhood AML patients than in adult patients (P < 0.05), and significantly shorter disease-free survival in patients with mutant FLT3 than in patients with wild-type FLT3 (P < 0.05). Our results suggest that the tandem duplication in the JM domain of the FLT3 gene is not a frequent phenomenon but might be a factor of poor prognosis in childhood patients with AML.

Retrospective analysis of clonality and detection of residual disease in myeloid leukemia by FISH on long-term stored bone marrow smears

BACKGROUND

Fluorescence in situ hybridization (FISH) has allowed the detection of numerical chromosomal aberrations in interphase nuclei on fresh or frozen smears of leukemia.

METHODS

To analyze clonality and residual disease in myeloid leukemia retrospectively, we applied FISH to bone marrow smears stored at ambient temperature for up to 9 years.

RESULTS

When hybridization efficiency was investigated on stored control smears from patients without hematological malignancy, more than 96% of nuclei showed the expected number of signals using DNA probes specific for chromosome 7, X or Y. In combination with cell morphology, we observed much higher hybridization efficiency in blasts and granulomonocytic cells compared with lymphoid and erythroid cells. On the basis of good hybridization efficiency for old smear specimens, we applied FISH to stored bone marrow smears of myeloid leukemias, in which either loss of chromosome 7 or loss of sex chromosomes had been verified previously by conventional cytogenetics (one patient with chronic myelomonocytic leukemia (CMML) and four with acute myeloid leukemia (AML; three M2 and one M7)). As a result, the loss of chromosome was detected in blasts from all patients and was observed in mature granulocytes, except in M7. In the CMML patient and one AML (M2) patient with t(8;21), lymphoid and erythroid cells also showed the loss of chromosomes, suggesting that it should occur at stem-cell level. A high amount of residual disease was detected in the morphological remission samples in one AML (M2) patient after induction therapy. The patient eventually succumbed to relapse.

CONCLUSION

Thus, the present FISH technique is useful to analyze the clinical significance of clonality and the residual disease in myeloid leukemia, retrospectively.

[Treatment results of intermittent and cyclic regimen with ATRA and chemotherapy in childhood acute promyelocytic leukemia. Children's Cancer and Leukemia Study Group]

An intermittent and cyclic regimen with All-Trans Retinoic Acid (ATRA) and intensive chemotherapy was conducted due to pharmacokinetic studies on ATRA for acute promyelocytic leukemia (APL) in children. We have treated 17 children with APL using ATRA for remission induction followed by an intermittent schedule of ATRA plus intensive chemotherapy (APL-ATRA protocol). There were 10 males and 7 females. The median age was 9.0 years old. The median baseline white blood cell count was 12.1 x 10(3)/microliter, hemoglobin 7.8 g/dl, platelet 4.5 x 10(4) microliters at diagnosis. Sixteen patients showed t(15; 17) translocation. RT-PCR analysis was available in 15 patients and showed PML/RAR alpha rearrangement in all patients. Overall, 13 or 17 newly diagnosed patients (88%) achieved complete remission and EFS was 67%. Compared to the control (same chemotherapy without ATRA regimen), remission induction and EFS were significantly increased. The toxicity of ATRA consisted of retinoic acid syndrome in 1 and pseudotumor cerebli in another. Other toxicities included headache, chelitis, gastrointestinal trouble and bone pain. These results suggest that intermittent and cyclic regimen with ATRA and intensive chemotherapy (APL-ATRA protocol) is highly effective for APL patients.

[Clonal analysis by fluorescence in situ hybridization in a patient with de nove acute myeloid leukemia with myelodysplasia]

A 12-year-old girl presenting leukocytosis, anemia and thrombocytopenia was diagnosed as de nove acute myeloid leukemia (AML, M2) with concurrent myelodysplastic features in myeloid and erythroid cells. Her karyotype was defined as 47, XX, +8[20]. Though she was treated successfully with multi-drug chemotherapy, she relapsed after 2 years of remission. A bone marrow transplantation from HLA matched her brother was performed to induce hematological remission which persisted for one year. She again relapsed with AML with myelodysplasia, and an abnormal complex karyotype was newly detected. She eventually died without further chemotherapy. We performed FISH on the patient's stained bone marrow smears using DNA probes for chromosome 8 and Y to analyze the clonality. The results showed that the most of blasts and bone marrow cells except lymphoid cells were of trisomy 8 at onset, while in the 1st remission, trisomy 8 clone was slightly detected only in monocytes. At 1st and 2nd relapse, trisomy 8 clone was detected again in most of myeloid cells. Thus, in this case, it was considered that underlying stem cell disorder with trisomy 8 during the entire disease course contributed to leukemogenesis.

A case of pseudo-Zellweger syndrome with a possible bifunctional enzyme deficiency but detectable enzyme protein. Comparison of two cases of Zellweger syndrome

Three infants with peroxisomal disorders were investigated clinicobiochemically and neuroradiologically. Two had classical Zellweger syndrome, and cranial CT scans showed typical disproportionate enlargement of the occipital horns of the lateral ventricles (colpocephaly) with marked hypodensity of the white matter. In one female infant, although the clinical findings were similar to those in Zellweger syndrome, some findings, such as elevated transaminase levels, liver fibrosis, the absence of renal cortical cysts and colpocephaly, were negative or milder. Biochemical analyses revealed increased very long-chain fatty acids, dicarboxylic aciduria and impaired beta-oxidation of lignoceric acid. However, peroxisomes were abundantly present in hepatocytes and cultured fibroblasts, and all peroxisomal beta-oxidation enzyme proteins were detected on immunoblot analysis. A cell fusion study suggested that the enzyme responsible for this case of 'pseudo-Zellweger syndrome' is bifunctional.

Zellweger syndrome and a microdeletion of the proximal long arm of chromosome 7

A 16-day-old girl with Zellweger syndrome and a chromosomal rearrangement, 46,XX,del(7)(q11.22q11.23), is reported. The diagnosis was confirmed by marked deficiencies of peroxisomal beta-oxidation enzymes and dihydroxyacetone phosphate acyltransferase activities in rectal cells and fibroblasts obtained by biopsy and in hepatic cells obtained at autopsy. This is the first report of Zellweger syndrome associated with a chromosomal arrangement, a microdeletion of chromosome 7. A tentative gene assignment to 7q11 is suggested.