Characterization of pediatric Philadelphia-negative B-cell precursor acute lymphoblastic leukemia with kinase fusions in Japan

Recent studies revealed that a substantial proportion of patients with high-risk B-cell precursor acute lymphoblastic leukemia (BCP-ALL) harbor fusions involving tyrosine kinase and cytokine receptors, such as ABL1, PDGFRB, JAK2 and CRLF2, which are targeted by tyrosine kinase inhibitors (TKIs). In the present study, transcriptome analysis or multiplex reverse transcriptase–PCR analysis of 373 BCP-ALL patients without recurrent genetic abnormalities identified 29 patients with kinase fusions. Clinically, male predominance (male/female: 22/7), older age at onset (mean age at onset: 8.8 years) and a high white blood cell count at diagnosis (mean: 94 200/μl) reflected the predominance of National Cancer Institute high-risk (NCI-HR) patients (NCI-standard risk/HR: 8/21). Genetic analysis identified three patients with ABL1 rearrangements, eight with PDGFRB rearrangements, two with JAK2 rearrangements, three with IgH-EPOR and one with NCOR1-LYN. Of the 14 patients with CRLF2 rearrangements, two harbored IgH-EPOR and PDGFRB rearrangements. IKZF1 deletion was present in 16 of the 22 patients. The 5-year event-free and overall survival rates were 48.6±9.7% and 73.5±8.6%, respectively. The outcome was not satisfactory without sophisticated minimal residual disease-based stratification. Furthermore, the efficacy of TKIs combined with conventional chemotherapy without allogeneic hematopoietic stem cell transplantation in this cohort should be determined.

Prognostic implications of CEBPA mutations in pediatric acute myeloid leukemia: a report from the Japanese Pediatric Leukemia/Lymphoma Study Group

CCAAT/enhancer-binding protein alpha (CEBPA) mutations are a favorable prognostic factor in adult acute myeloid leukemia (AML) patients; however, few studies have examined their significance in pediatric AML patients. Here we examined the CEBPA mutation status and clinical outcomes of pediatric AML patients treated in the AML-05 study. We found that 47 (14.9%) of the 315 evaluable patients harbored mutations in CEBPA; 26 cases (8.3%) harbored a single mutation (CEBPA-single) and 21 (6.7%) harbored double or triple mutations (CEBPA-double). After excluding core-binding factor-AML cases, patients harboring CEBPA mutations showed better overall survival (OS; P=0.048), but not event-free survival (EFS; P=0.051), than wild-type patients. Multivariate analysis identified CEBPA-single and CEBPA-double as independent favorable prognostic factors for EFS in the total cohort (hazard ratio (HR): 0.47 and 0.33; P=0.02 and 0.01, respectively). CEBPA-double was also an independent favorable prognostic factor for OS (HR: 0.30; P=0.04). CEBPA-double remained an independent favorable factor for EFS (HR: 0.28; P=0.04) in the normal karyotype cohort. These results suggest that CEBPA mutations, particularly CEBPA-double, are an independent favorable prognostic factor in pediatric AML patients, which will have important implications for risk-stratified therapy.

Comparison of matched-sibling donor BMT and unrelated donor BMT in children and adolescent with acquired severe aplastic anemia

From January 1991 to March 2007, 61 children and adolescent with acquired severe aplastic anemia received BMT in our institutions. We retrospectively compared the outcome of 30 cases of matched-sibling donor BMT (MSD-BMT) and 31 cases of unrelated donor BMT (URD-BMT). We observed one graft failure among MSD-BMT recipients and three graft failures among URD-BMT recipients, respectively. No patients in the MSD-BMT group developed grades II-IV acute GVHD compared with 11 of 30 patients (37%) in the URD-BMT group (P<0.001). One of 30 MSD-BMT recipients (3%) developed chronic GVHD compared with 8 of 30 URD-BMT recipients (27%) (P=0.013). The incidence of EBV and CMV reactivation was 11 of 20 URD-BMT recipients and 23 of 30, respectively. One patient in the URD-BMT group died of a motor accident 5.5 years after BMT. Ten-year OS was 100% in MSD-BMT recipients and 93.8% (95% CI, 81.9-100%) in URD-BMT recipients, respectively (P=0.252). Ten-year failure-free survival was 96.7% (95% CI, 90.2-100%) in the MSD-BMT group and 84.7% (95% CI, 70.2-99.2%) in the URD-BMT group, respectively (P=0.161).

Outcome of risk-based therapy for infant acute lymphoblastic leukemia with or without an MLL gene rearrangement, with emphasis on late effects: a final report of two consecutive studies, MLL96 and MLL98, of the Japan Infant Leukemia Study Group

We evaluated the efficacy of a treatment strategy in which infants with acute lymphoblastic leukemia (ALL) were stratified by their MLL gene status and then assigned to different risk-based therapies. A total of 102 patients were registered on two consecutive multicenter trials, designated MLL96 and MLL98, between 1995 and 2001. Those with a rearranged MLL gene (MLL-R, n=80) were assigned to receive intensive chemotherapy followed by hematopoietic stem cell transplantation (HSCT), while those with germline MLL (MLL-G, n=22) were treated with chemotherapy alone. The 5-year event-free survival (EFS) rate for all 102 infants was 50.9% (95% confidence interval, 41.0-60.8%). The most prominent late effect was growth impairment, observed in 58.9% of all evaluable patients in the MLL-R group. This plan of risk-based therapy appears to have improved the overall prognosis for infants with ALL, compared with previously reported results. However, over half the events in patients with MLL rearrangement occurred before the instigation of HSCT, and that HSCT-related toxic events comprised 36.3% (8/22) of post-transplantation events, suggesting that further stratification within the MLL-R group and the development of more effective early-phase intensification chemotherapy will be needed before the full potential of this strategy is realized.

The seventh international childhood acute lymphoblastic leukemia workshop report: Palermo, Italy, January 29--30, 2005

Between 1995 and 2004, six International Childhood Acute Lymphoblastic Leukemia (ALL) Workshop have been held, and the completion of several collaborative projects has established the clinical relevance and treatment options for several specific genetic subtypes of ALL. This meeting report summarizes the data presented in the seventh meeting and the discussion.

Pathology review for paediatric non-Hodgkin's lymphoma patients in Japan

A central pathology review system with an immunophenotyping laboratory was established in Japan to support the clinical trial, the Japan Association of Childhood Leukaemia Study (JACLS) NHL-98, for patients with paediatric non-Hodgkin's lymphoma (NHL). Pathology samples from 155 clinically-suspected NHL cases were evaluated centrally initially using the Revised European-American Lymphoma (REAL) classification in a rapid review (within 2 weeks after surgery/biopsy) and then later at the consensus review (once a year). The samples were subsequently re-classified according to the new World Health Organisation (WHO) classification. After the pathology review, 96 (62%) patients were eligible for the study, and 58 of them (60%) had extra-nodal primaries. These NHL cases included B-cell lymphomas (precursor B-cell, 11; Burkitt, 18; diffuse large B-cell, 18; not otherwise specified, 3) and T/Natural Killer (NK)-cell lymphomas (precursor T-cell, 23; anaplastic large cell, 20; others, 3). There was excellent concordance in making the diagnoses (95/96, 99%) and typing (93/96, 97%) of NHL between the rapid and consensus reviews. Five cases, initially diagnosed as diffuse large B-cell lymphoma by the review, were re-classified as Burkitt lymphoma according to the immunocytochemical criteria by the WHO classification. A total of 59 (38%) cases were excluded from the study: they were Hodgkin lymphoma (7), leukaemias (11), reactive lymphoid hyperplasia (20), necrotizing lymphadenitis (7), no consensus diagnosis (1), insufficient materials (2), and others (11). This is the first report of the central pathology review from the paediatric NHL group study in Japan. Because various diseases, either neoplastic or reactive, mimicked NHL, clinically and histopathologically, the central pathology review system was critical and essential for patient enrollment and protocol assignment in our clinical trial. Through the two-step review system, highly reliable data were generated to support this study.

Flow cytometric determination of intracytoplasmic Wiskott-Aldrich syndrome protein in peripheral blood lymphocyte subpopulations

We have produced a novel monoclonal antibody (mAb) directed against Wiskott-Aldrich syndrome protein (WASP) by immunizing mice with the recombinant protein. The mAb designated 5A5 is highly specific to WASP and suitable for Western blot analysis and immunoprecipitation. A flow cytometric assay using the 5A5 mAb identifies expression of intracytoplasmic WASP in lymphocytes from normal individuals. Double staining analysis with cell surface CD3, CD19, and CD56, and intracytoplasmic molecules revealed WASP expression in each subpopulation. With regard to WASP expression in patients with Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT), peripheral blood mononuclear cells (PBMCs) from nine patients and Epstein-Barr virus-transformed B-lymphoblastoid cell lines from seven patients examined did not show WASP expression by flow cytometric analysis. These results were confirmed by Western blot analysis. We conclude that WASP expression in lymphocyte subpopulations from patients with WAS and XLT can be more precisely evaluated by flow cytometry as compared with Western blot analysis. This flow cytometry method is important as a supplement to Western blots, but even more important as an alternative and powerful assay that can contribute to research on WASP as well as diagnosis in a clinical setting.

Effects of operating conditions on selectivity of a plasma fractionator in double filtration plasmapheresis

In a typical double filtration plasmapheresis treatment, plasma fractionation between albumin and some immunoglobulins associated with toxins is limited because none of the currently available plasma fractionators has a strict cutoff property for these proteins. Selectivity of immunoglobulins over albumin depends not only on the cutoff properties of the membrane but on the operating conditions such as the flow rate of the supplied plasma (Q(P)) and retained plasma to be discarded (Q(D)) in the plasma fractionator. We carried out an in vitro study using human plasma harvested by single plasma exchange treatments to assess the selectivity of a plasma fractionator, Evaflux 2A-F (Kawasumi Laboratories, Inc., Tokyo, Japan), under various operating conditions. The results of rate-constant filtration experiments showed that the concentrations in the feed tank and the sieving coefficient (SC) values of every protein were decreased slightly within 2 h after the start of the experiment because of membrane trapping, adsorption, and/or plugging. The time-averaged SC value of albumin increased with flow rate ratio (Q(P)/Q(D)) due to increasing filtration fraction (FF), but relative removal efficiency (mD/mP*) for albumin decreased with Q(P)/ Q(D) due to decreasing Q(D). For immunoglobulins, on the other hand, the SC values were almost unchanged, and the mD/mP* values increased with Q(P)/Q(D) due to an increase in FF. Both increasing Q(P) and decreasing Q(D) are effective means of improving selectivity between these proteins in the plasma fractionator. Membrane fouling is, however, obvious beyond a Q(P)/Q(D) value that is thought to be a critical point. Operation should be conducted below the critical Q(P)/Q(D) value, which depends on the patient's plasma components and the cutoff property of the membrane.

Age-related changes in brain neuromagnetic responses to face perception in humans

In order to investigate the effects of ageing on face perception, we studied the magnetic responses to face images in 15 young (19-38 years) and 10 elderly (51-81 years) subjects. Face-specific responses (160mF), which originate in the inferior occipitotemporal cortices, and face non-specific responses (100m), which originate in the primary visual cortices, were evoked in all subjects. Averaged peak latency of the 160mF in the elderly group (174.0+/-9.1 ms) was significantly longer (P<0.0005) than that in the young group (161.5+/-5.1 ms), while no inter-group difference was found in the 100m latency. There was a significant correlation between age and 160mF latency (+0.35 ms/year, R=0.747) suggesting age-related decline of face perception.

Prospective monitoring of the Epstein-Barr virus DNA by a real-time quantitative polymerase chain reaction after allogenic stem cell transplantation

Epstein-Barr virus (EBV)-related lymphoproliferative disorder (LPD) is a serious complication of haematopoietic stem cell transplantation (HSCT). To clarify the frequency, natural course and risk factors for LPD, we prospectively monitored 38 allogeneic (allo)-HSCT patients, focusing on the use of anti-thymocyte globulin (ATG). We used a recently developed real-time polymerase chain reaction assay to monitor EBV genome load. The subjects consisted of 19 patients given ATG for conditioning and 19 patients not given ATG. Of the 19 patients given ATG, 47.4% (nine patients) had a significant increase in EBV genome load (10(2.5) copies/microg DNA). Of these nine patients, two developed LPD. Therefore, 10.5% of the patients receiving allo-HSCT with ATG developed LPD. In contrast, none of the 19 patients without ATG had a significantly increased EBV load. The increases in viral load were observed in the second or third month after HSCT. We found that the peak viral loads of LPD patients were > 10(4.0 ) copies/microg DNA. On the other hand, the viral loads of most patients with no symptoms were < 10(2.5) copies/microg DNA. In conclusion, routine monitoring of EBV load during the second and third months after transplantation may benefit patients undergoing HSCT with ATG. We propose that an EBV load > 10(2.5) copies/microg DNA is the reactivation of EBV, and that an EBV load > 10(4.0) copies/microg DNA is indicative of developing LPD.

Unrelated donor marrow transplantation in children with severe aplastic anaemia using cyclophosphamide, anti-thymocyte globulin and total body irradiation

We report a favourable outcome in 15 patients with severe aplastic anaemia (SAA) who were < 20 years of age and who underwent bone marrow transplantation (BMT) from a human leucocyte antigen (HLA)-matched unrelated donor. All patients were non-responders to intensive immunosuppressive therapy (IST) and were multiply transfused. The conditioning regimen consisted of cyclophosphamide (60 mg/kg/d, on d -4 and -3), anti-thymocyte globulin (2.5 mg/kg/d, on d -5 to -2) and total body irradiation (2.5 Gy x 2/d, on d -2 and -1). Patients received cyclosporine and methotrexate for prophylaxis of graft-versus-host disease (GVHD), except for the last four who received tacrolimus instead of cyclosporine. Donor/recipient pairs were identical for HLA class I and II antigens by serological typing, but four pairs were found to have a mismatch at the HLA-A, -B or -DRB1 locus by high-resolution typing. All patients achieved rapid engraftment and are alive at 2-86 months after transplantation (median follow-up, 51 months). Moderate to severe acute GVHD occurred in 5 out of 15 patients (33%); only one patient developed extensive chronic GVHD. Considering our encouraging results, unrelated donor transplantation for SAA is recommended as a salvage therapy in non-responders to IST.

Clinicopathologic characteristics of leukemia in Japanese children and young adults

The aim of this study is to clarify the clinicopathologic characteristics of adolescent leukemia in Japan by retrospective analysis. Patients with acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), chronic myelogenous leukemia (CML), and myelodysplastic syndrome (MDS), consecutively diagnosed from 1986 to 1999, were enrolled. A total of 3,856 patients from 1 to 15 years of age and 1,803 patients from 15 to 29 years of age were eligible for this study. Demographically, the frequency of AML found was almost constant during the teenage years, whereas the frequency of ALL gradually decreased. The relative frequency of CML and MDS apparently started to increase in patients in their late teens. The relative frequency of M3 and t(15;17) gradually increased during adolescence. Among patients aged 1 to 4 years, M7 was the most frequent FAB subtype. Among patients aged 5 to 9 years, M2 and t(8;21) was the most frequent subtype. The percentage of T cell ALL increased in patients 5 to 9 years old, reaching 31.2% in the 20- to 24-year-old age group. The percentage of patients with hyperdiploidy over 50 chromosomes was highest (17.0%) in patients aged 1 to 4 and decreased to 3.9% in the older teens. The percentage of patients with the Ph1 chromosome increased from 9.9% in teens to 30.0% in patients in their late twenties. When comparing event-free survival (EFS) rates for ALL according to age, the estimated 7-year EFS rate was highest for patients aged 1 to 9 years (65.9%) and intermediate for patients aged 10 to 15 years (48.4%). However, the EFS rate was significantly worse for patients aged 15 to 19 years (19.4%) and 20 to 29 years (17.0%) (P = 0.024). On the other hand, the EFS rate for AML decreased with increasing age, although without statistical significance. The overall survival rates are approximate among all age groups. The results of the study indicate that there are considerable variations in biologic features of leukemia between children and young adults. The prognosis for adolescent leukemia may be improved by introducing pediatric trials, which take into account the prognostic biological features.

Correlation between HHV-6 infection and skin rash after allogeneic bone marrow transplantation

We investigated whether a causal relationship exists between human herpesvirus 6 (HHV-6) and skin rash resembling acute graft-versus-host disease (GVHD) following bone marrow transplantation (BMT). Isolation of HHV-6 was used to monitor active HHV-6 infection in this study. We analyzed 25 episodes of skin rash in 22 recipients. All recipients were seropositive for HHV-6 before BMT. The onset of skin rash started prior to 30 days post transplantation (group A) in 15 of 25 cases, but after that (group B) in the remaining 10 cases. Twenty-five skin tissue samples were obtained from 22 recipients. The HHV-6 genome was detected in four of 15 skin samples from group A, but not detected in those from group B. HHV-6 was isolated from 11 of 22 recipients around 2 to 3 weeks after BMT (range 14 to 28 days after BMT). HHV-6 was isolated at a time between 10 days before and after the onset of skin rash (skin rash-related viremia) in nine cases in group A. Meanwhile, no skin rash-related viremia was observed in group B. Of the four recipients with positive detection of HHV-6 genome in their skin tissue (group A), two had HHV-6 viremia at the same time. The association between the timing of HHV-6 infection and the onset of skin rash was analyzed statistically. HHV-6 viremia (skin rash-related viremia) was found in nine of 15 (60%) cases in group A, compared with none of 10 (0%) cases in group B. This difference was statistically significant (P = 0.008). Moreover, HHV-6 infection (skin rash-related viremia and/or positive detection of HHV-6 DNA in skin tissue) was demonstrated in 11 of 15 (73.3%) cases in group A, compared with none of 10 (0%) cases in group B (P = 0.001). Thus, this study suggests that HHV-6 may be involved in the development of skin rash in the first month after allogeneic BMT.

Risk factors for chronic graft-versus-host disease after allogeneic stem cell transplantation in children

We analyzed the incidence and risk factors for chronic graft-versus-host disease (GVHD) in 265 children undergoing allogeneic stem cell transplantation (SCT) who survived longer than 3 months post SCT. Patients transplanted from HLA-mismatched related donors and matched unrelated donors were included. Fifty-five patients developed chronic GVHD between 1 and 25 months after SCT, and the 5-year cumulative incidence of chronic GVHD was 22%. By multivariate analysis, acute GVHD (P = 0.004), malignant disease (P = 0.004), recipient age (> or =10 years) (P = 0.01) and a female donor to male recipient (P = 0.035) were significant risk factors for chronic GVHD. When acute GVHD was excluded from the multivariate analysis, malignant disease (P = 0.002) and older recipient age (P = 0.007) were identified. The incidence of chronic GVHD in this childhood study was lower than that observed in adults, and recipient age was an important factor in childhood SCT. The high incidence associated with malignant disease may be affected by changes in GVHD prophylaxis in order to ensure graft-versus-tumor effects.

Membrane permeabilization induced by discodermin A, a novel marine bioactive peptide

The effects of discodermin A (DC-A), a novel marine bioactive peptide extracted from sea sponge Discodermia kiiensis, on the vascular smooth muscle cells and tissues were examined. Analysis with a confocal laser microscope showed that DC-A (0.1-30 microM) permeabilized the plasma membrane of A10 cells to the non-permeable fluorescent agents, ethidium homodimer-1 (MW = 857) and calcein (MW = 623), in a concentration-dependent manner. In the vascular tissue treated with 30 microM DC-A, addition of a micromolar concentration of Ca(2+) evoked a sustained contraction in the presence of ATP, suggesting that DC-A increased the permeability of the membrane to Ca(2+) and ATP. DC-A at higher concentrations (30 microM) significantly increased the leakage of lactate dehydrogenase (140 kD) from the vascular tissue. These results suggest that DC-A has a permeabilizing effect on the plasma membrane possibly by interacting with plasma membrane phospholipids with its six successive hydrophobic amino acid residues at N-terminal.

Distribution of natural antibody against human neuroblastoma among children with or without neuroblastoma

BACKGROUND

This study was conducted to examine the distribution of a natural antibody against neuroblastoma (NB) among Japanese children and to clarify the clinical significance of the presence of this antibody in the sera during treatment in patients with International Neuroblastoma Staging System Stage 4 NB.

PROCEDURE

Human sera were obtained from 8 healthy volunteers, 82 patients with non-malignant surgical diseases, and 35 patients with NB including 3 with Stage 1 disease, 6 with Stage 2, 7 with Stage 3, 17 with Stage 4, and 2 with Stage 4S. This natural antibody was quantified by flow cytometry and its anti-tumor activity was measured by complement-dependent cytotoxicity (CDC) using TGW cells, a human NB cell line, as the target.

RESULTS

IgM antibody and CDC activity against NB could be detectetd in all sera from healthy volunteers and from patients with non-malignant surgical dis eases who were age >1 year. The amount of IgM antibody and CDC activity in sera from patients with Stage 4 NB at diagnosis consistently was low, most likely because of massive absorption by tumor cells. In this group of patients, the increased CDC activity detected during treatment was indicative of a favorable factor for survival.

CONCLUSIONS

A natural antibody against NB appears to exist in the sera of Japanese children. The sequential assessment of the levels of this antibody in the sera from Stage 4 NB patients during treatment may serve as a prognostic indicator.

Disease outcome may be predicted by molecular detection of minimal residual disease in bone marrow in advanced neuroblastoma: a pilot study

PURPOSE

This pilot study focussed on whether sequential molecular detection of minimal residual disease (MRD) in bone marrow (BM) could predict the outcome of patients with advanced neuroblastoma.

PATIENTS AND METHODS

Bone marrow samples from 21 patients older than age 12 months with stage IV neuroblastoma were sequentially examined for tumor cell contamination by detecting tyrosine hydroxylase (TH) messenger ribonucleic acid (mRNA) using reverse transcription-polymerase chain reaction (RT-PCR). Twenty patients received myeloablative therapy with hematopoietic stem cell transplantation after achieving complete remission.

RESULTS

All BM samples of patients except that of one patient was cytologically positive for neuroblastoma cells at diagnosis, and they became negative for neuroblastoma cells within 3 months by cytologic examination. By RT-PCR analysis, BM samples of all patients were positive for TH mRNA at diagnosis, and samples of 19 patients became negative for TH mRNA 1 to 13 months after the start of chemotherapy. Six patients whose BM samples became negative for TH mRNA within 4 months after the start of chemotherapy remained alive without evidence of disease (median 76 mos, range 36-91). In contrast, out of 15 patients whose BM samples remained positive, 10 patients had relapse develop and 9 patients died from disease (median 15 mos, range 10-25). There was a statistically significant difference in disease-free survival between the two groups (P < 0.05).

CONCLUSION

Persistence of MRD in BM may predict poor prognosis in advanced neuroblastoma.

Outcome prediction by molecular detection of minimal residual disease in bone marrow for advanced neuroblastoma

BACKGROUND

We have determined whether sequential molecular detection of minimal residual disease (MRD) in bone marrow (BM) could predict the outcome of patients with advanced neuroblastoma (NB).

PROCEDURE

Bone marrow samples from 19 patients over 12 months of age with stage 4 neuroblastoma were sequentially examined for tumor cell contamination by detecting tyrosine hydroxylase (TH) mRNA using reverse transcription-polymerase chain reaction (RT-PCR). All patients received repetitive multi-drug chemotherapy including cisplatin, cyclophosphamide or ifosphamide, adriamycin, and etoposide or vincristine. Seventeen patients received myeloablative therapy with hematopoietic stem cell transplantation after achieving complete remission.

RESULTS

All but one patient were histologically positive for tumor cells in BM samples at diagnosis, and they became negative for tumor cells within 3 months histologically. By the RT-PCR analysis, all patients were positive for TH mRNA in BM samples at diagnosis, and they became negative for TH mRNA 1 to 13 months after the start of chemotherapy. Six patients whose BM samples became negative for TH mRNA within 4 months after the start of chemotherapy remained alive without evidence of disease (median 61 months, range 20-76). In contrast, 12 of 13 patients whose BM samples remained positive at that time developed relapse and 10 of them died of disease (median 24 months, range 13-43). There was a statistically significant difference in survival between the two groups (P < 0.05). No significant difference of clinical characteristics by the MRD positivity at 4 months after the start of chemotherapy.

CONCLUSIONS

Persistence of MRD in BM at 4 months after the start of chemotherapy could predict poor prognosis in advanced neuroblastoma.

Allogeneic hematopoietic transplantation of CD34+ selected cells from an HLA haplo-identical related donor. A long-term follow-up of 135 patients and a comparison of stem cell source between the bone marrow and the peripheral blood

We studied the outcome of allogeneic transplants in 135 patients who received selected BM and/or PBSC CD34+ cells from HLA haplo-identical related donors. Donor engraftment was achieved in 108 of 128 evaluable transplants. Engraftment failure occurred more often in non-malignant than in malignant diseases (10 of 25 vs 17 of 103, P = 0.010). The CD34+ cell dose was associated with the speed of neutrophil and platelet recovery, but the cell source was not. Acute GVHD (> or = grade II) developed in 21.0 +/- 3.7%. Chronic GVHD occurred more frequently in malignancies than in non-malignancies (44.1 +/- 7.6% vs 0.0%, P = 0.0075), and more in PBSC recipients than in BM recipients (53.6 +/- 9.4% vs 17.4 +/- 9.3%, P = 0.0054). Relapse rate was higher in high risk patients than in standard risk patients (78.7 +/- 7.1% vs 22.1 +/- 10.0%, P = 0.0001). Probabilities of disease-free survival (DFS) were 14.2 +/- 3.5% in malignancies and 25.7 +/- 9.2% in non-malignancies. Probabilities of DFS in standard and high risk patients were 39.4 +/- 9.2% and 5.7 +/- 2.8% (P = 0.0001). A high incidence of graft failure, infection and relapse was observed and resulted in high mortality.

Monitoring four herpesviruses in unrelated cord blood transplantation

Cord blood transplantation, which has lower risk of graft-versus-host disease than bone marrow transplantation, might have higher risk of infections. A system to quantify four herpesviruses, CMV, human herpesvirus 6 (HHV6), EBV, varicella-zoster virus using the real-time PCR assay was established and applied for prospective viral load monitoring in three recipients undergoing cord blood transplantation. CMV and HHV6 were detected in peripheral blood from all three recipients, while EBV was detected in two. Varicella-zoster virus was not detected at all. At the peak of HHV6 or CMV, each patient showed virus-related symptoms. During the pre-transplant period, CMV DNA was detected in two recipients who later developed CMV-related diseases. These observations indicate that our system is not only useful for managing herpesviruses infections in transplant recipients, but also a powerful method for clarifying the relationships between the viral load and clinical symptoms.

Absence of mutations in the granulocyte colony-stimulating factor (G-CSF) receptor gene in patients with myelodysplastic syndrome/acute myeloblastic leukaemia occurring after treatment of aplastic anaemia with G-CSF

The development of myelodysplastic syndrome/acute myeloblastic leukaemia (MDS/AML) has been reported in patients with aplastic anaemia (AA) after administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF). Similarly, patients with severe congenital neutropenia (SCN) have an increased risk of developing MDS/AML after treatment with rhG-CSF. Point mutations in the G-CSF receptor gene are found in about 20% of SCN patients who are predisposed to MDS/AML. We investigated the occurrence of mutations in the G-CSF receptor in eight patients with AA who developed MDS/AML. No mutations were detected around the cytoplasmic domain of the gene in our patients, indicating that the mechanisms of clonal evolution to MDS/AML in patients with AA might be different from those with SCN.

Real-time quantitative reverse transcription-polymerase chain reaction for the detection of AML1-MTG8 fusion transcripts in t(8;21)-positive acute myelogenous leukemia

Quantification of AML1-MTG8 fusion transcripts was performed by using real-time reverse transcription-polymerase chain reaction (RT-PCR) and the clinical value of this method was evaluated in t(8;21)-positive acute myelogenous leukemia (AML). A t(8;21)-positive cell line, Kasumi-1, was used for constructing standard curves and the corrected AML1-MTG8 mRNA expression level relative to the expression of the GAPDH housekeeping gene was calculated. Bone marrow samples from 14 patients with t(8;21)-positive AML were sequentially examined. The corrected AML1-MTG8 expression level at diagnosis varied in the range from 0.4 to 2.7 (median, 1.5) among the patients. When samples at 1, 3 and 6 months were examined after diagnosis, the corrected AML1-MTG8 expression level was found to decrease sequentially in all but one. AML1-MTG8 fusion transcripts were also detected in four of eight samples from patients in remission for more than 1 year. In conclusion, real-time RT-PCR can provide a rapid and accurate quantification of AML1-MTG8 fusion transcripts. This system could be useful to reveal the prognostic relevance of minimal residual disease in t(8;21)-positive AML.

[Clinical features of essential thrombocythemia in three children]

Essential thrombocythemia (ET) is one of the quite rare myeloproliferative disorders in children. The natural course and outcome of this disease have been reported to vary. We report three children (two boys and one girl, mean age at diagnosis 12 yr) with ET who showed different clinical courses. The girl was asymptomatic, but the boys had ankle pain and priapism, respectively. The platelet count ranged between 2300 and 2900 x 10(9)/L, and the diagnoses were made according to the criteria of the Polycythemia Vera Study Group. The serum thrombopoietin level reached 0.33 and 0.47 fmol/ml in two patients. All three children were administered aspirin or dipyridamole orally. Normalization of the platelet count was observed in two patients, and stable disease persisted in one. The 12 pediatric patients with ET reported previously in Japan demonstrated a low incidence of serious thrombohemorrhagic complications and a favorable outcome, none developing acute leukemia. Careful continuous observation and conservative treatment may be preferable in pediatric patients who do not have cardiovascular symptoms, avoiding the use of potential leukemogens such as alkylating agents and hydroxyurea.

Long-term outcome of acquired aplastic anaemia in children: comparison between immunosuppressive therapy and bone marrow transplantation

A total of 100 children under the age of 17 years with acquired aplastic anaemia (AA) were initially treated with immunosuppressive therapy (IST) (n = 63) or bone marrow transplantation (BMT) (n = 37) from an HLA-matched family donor. The projected 10-year survival rates were 55 +/- 8% and 97 +/- 3% respectively (P = 0.004). Because the IST group included 11 non-responders who were salvaged by BMT from an HLA-matched unrelated donor, we compared failure-free survival (FFS) between the groups. The probability of FFS at 10 years was 97 +/- 3% for the BMT group, compared with 40 +/- 8% for the IST group (P = 0.0001). Seven patients evolved to myelodysplastic syndrome (MDS) with monosomy 7 and the estimated cumulative incidence of MDS 10 years after diagnosis was 20 +/- 7% in the IST group. We compared the outcome of children treated with IST during the two consecutive periods of 1983-91 (group A, n = 40) and 1991-8 (group B, n = 23) to assess the impact of combined therapy with antithymocyte globulin and cyclosporin. The probability of FFS at 7 years follow-up was the same in the two groups (50 +/- 8% vs. 40 +/- 15%, P = 0.40). We recommend BMT as first-line therapy in paediatric severe AA patients with an HLA-matched family donor. Alternative donor BMT is recommended as salvage therapy in patients who relapse or do not respond to initial IST.

Longitudinal dynamics of Epstein-Barr virus-specific cytotoxic T lymphocytes during posttransplant lymphoproliferative disorder

Epstein-Barr virus (EBV)-associated lymphoproliferative disorder (LPD) is a serious complication after allogeneic bone marrow transplantation (BMT). Dynamics of EBV-specific cytotoxic T lymphocytes (CTL), which are important in controlling EBV during the LPD, have not been fully elucidated. A patient with Wiskot-Aldrich's syndrome was diagnosed as suffering from LPD on day 47 after BMT. Fluorescence-activated cell sorter (FACS) analysis for interferon-gamma production revealed that >70% of the patient's CD8(+) T cells were EBV specific. The patient's lymphocytes were directly cytotoxic to donor-derived EBV-positive lymphoblastoid cells, which was blocked by an anti-class I antibody. EBV-specific CD8(+) T cell counts declined in parallel with EBV genome load, and full recovery of LPD was obtained with relaxation of immunosuppressive drugs. The results illustrate longitudinal dynamics of EBV-specific CTL during the posttransplant LPD; they also illustrate the advantages of using FACS analysis for EBV-specific CTL to make decisions about treatment.

Prognostic impact of telomerase activity in patients with neuroblastoma

Neuroblastoma is one of the most common malignant neoplasms occurring among children. The prognosis for this disease is strongly associated with age, disease stage, histology, and some biologic features. It has been reported that telomerase, a ribonucleoprotein enzyme, which maintains the telomere length in immortal cells, is related to disease stage and other biologic features. The purpose of this study was to evaluate the prognostic value of telomerase activity compared to TrkA expression in 65 patients with neuroblastoma. Telomerase activity and TrkA expression were examined in tissue samples collected between 1980 and 1994 from 65 patients by polymerase chain reaction-based telomerase activity. TrkA expression was examined by immunoblotting using a rabbit anti-gp140 proto-trk polyclonal antibody. Low telomerase activity was found in 22 of 30 (73.3%) patients with Stages 1, 2, or 4S neuroblastomas; 7 of 13 (53.8%) with Stage 3; and 8 of 22 (36.3%) with stage 4; no telomerase activity was detected in 7 of 22 (31.8%) patients with Stage 4 neuroblastoma. The 5-year event-free survival (EFS) rate was 86.5% for patients with low telomerase activity, while it was 53.8% for patients with high telomerase activity. By the combination of telomerase activity and TrkA expression, the 5-year EFS rate was highest among patients with a high TrkA expression and a low or non-existent telomerase activity (91.7%), and it was lowest among patients with a low TrkA expression and a high telomerase activity (29.6%). Thus, it appears that telomerase activity would be a useful prognostic factor for neuroblastoma, especially when used in combination with the TrkA expression.

Prognostic factors in childhood acute lymphoblastic leukemia in Japan. Japan Association of Childhood Leukemia Study

A retrospective analysis of children with acute lymphoblastic leukemia (ALL) was performed to evaluate the current status of diagnosis and treatment of ALL in Japanese children. Clinical records of 670 children with ALL were collected and analyzed; these children had been diagnosed between 1991 and 1995 at the 53 institutions in 4 areas participating in the Japan Association of Childhood Leukemia Study. It was found that T-cell ALL was significantly less frequent in Tokai and Hokkaido than in Kansai and Chu-Shikoku. The overall induction rate was 92.4%. The estimated 7-year overall survival rate and event-free survival (EFS) rate were 76.0% +/- 1.9% and 61.4% +/- 2.1%, respectively. EFS rates were significantly different among the geographic areas. In female patients with B-cell precursor (B-pre) ALL and white blood cell counts at diagnosis (WBCsdiag) below 50.0 x 10(9)/L, favorable outcomes were significant. Favorable outcomes were not significant in B-pre ALL patients with a WBCdiag above 50.0 x 10(9)/L or in T-cell ALL patients. The EFS rate for infants was significantly worse than that for patients over 1 year of age. In B-pre ALL, but not in T-cell ALL, it was found that the higher the WBCdiag, the worse the EFS rate. Multivariate analysis showed that the following factors were significantly unfavorable for EFS: the Philadelphia chromosome, an translocations associated with chromosome 11q23, an acute unclassified leukemia, mixed-lineage leukemia, a WBCdiag above 100.0 x 10(9)/L, and male gender. Hyperdiploidy (> 50 chromosomes) was significantly favorable for EFS. For further tailoring of treatment and to improve the outcome in childhood ALL, a prospective large-scale study should be undertaken in Japan.

Experimental study of critical exponents of electrical conductivity in a two-dimensional continuum percolation system

In this paper an experimental study is presented for critical exponents of electrical conductivity in an inverse Swiss-cheese model. Filled circles are drawn on random positions of square paper in drawing ink with an X-Y plotter, and electrical resistance between both opposite sides is measured automatically by the use of general purpose interface bus system. Electrical conductivity is obtained from the inverse of the electrical resistance. Electrical conductivity in a bond process is also measured with the same system. It is confirmed that the critical exponent of electrical conductivity of a continuum two-dimensional inverse Swiss-cheese model is different from that of a discrete one.

Hemophagocytosis by leukemic blasts in 7 acute myeloid leukemia cases with t(16;21)(p11;q22): common morphologic characteristics for this type of leukemia

BACKGROUND

In a previous study of a case of acute megakaryoblastic leukemia with t(16;21)(p11;q22), which displayed hemophagocytosis by leukemic blasts, the authors mentioned that the same type of morphology had been cited in the literature for 4 other cases of acute myeloid leukemia (AML) with the same translocation. This observation prompted the authors to examine more cases of AML with t(16;21)(p11;q22) for this morphology.

METHODS

The authors reviewed bone marrow smears for the presence of hemophagocytosis in 7 patients with AML identified as having t(16;21)(p11;q22).

RESULTS

The leukemias belonged to the FAB-M1/M7 (n = 5), M5b (n = 2), and contained phagocytic blasts in various percentages (< 0.2-36.7%). The blasts contained either single or multiple cytoplasmic vacuoles, in some of which the phagosomes were visible. The engulfed hemopoietic cells (red cells, erythroblasts, lymphocytes, and thrombocytes) were also noted in their cytoplasm. These observations confirmed that hemophagocytosis by leukemic blasts is a common and characteristic feature of this type of leukemia.

CONCLUSIONS

The study of 12 cases (the 7 cases described here and the previous 5 cases) strongly supports the hypothesis that hemophagocytosis by leukemic blasts is common and characteristic in this type of leukemia, which may be related to the specific chromosome aberration of t(16;21)(p11;q22).

Bone marrow transplantation for children with acute myelogenous leukaemia in the first complete remission

Of 52 children aged 9 months to 16 years old with acute myelogenous leukaemia (AML) in first complete remission undergoing bone marrow transplantation at our institution, 31 received allogeneic transplants (allo-BMT) and 21 received autologous transplants (ABMT). Initial induction and consolidation chemotherapy were not uniform. BMT was performed at a median of 7 months (range: 2.5 to 22.5 months) from the diagnosis. Conditioning included chemotherapy (n=43: 4 x 4 mg/kg of busulfan and 3 x 60 to 70 mg/m(2) of melphalan) or total body irradiation (12 Gy) plus chemotherapy (n=9). Graft-versus-host disease (GVHD) prophylaxis in allo-BMT cases consisted of methotrexate +/- cyclosporin A. Unpurged marrow was used in ABMT cases. All patients showed sustained engraftment. Amongst allograft cases, acute or chronic GVHD developed in 7 patients each (23%). 8 patients (15%) died (5 with allo-BMT, 3 with ABMT), including transplant-related mortality in 3 of the allo-BMT patients. 7 patients had relapses (3 with allo-BMT, 4 with ABMT). As of June 1999, 43 patients are alive and well 13 to 160 months after BMT (median, 71), with 5-year disease-free survival rates after BMT of 84% for allo-BMT, 81% for ABMT and 83% altogether. Although the presented data are based on a retrospective evaluation, we consider BMT for childhood AML during first complete remission an effective treatment for eradicating leukaemia.

Prognostic value of internal tandem duplication of the FLT3 gene in childhood acute myelogenous leukemia

BACKGROUND

Recently, an internal tandem duplication of the FLT3 gene (FLT3/ITD) was found in 20% of adult cases of acute myelogenous leukemia (AML), and this length abnormality was suggested to be associated with leukemic progression.

PROCEDURE

We examined the mRNA expression of the FLT3 gene by using reverse transcription-polymerase chain reaction (RT-PCR) in 64 children with AML, and further abnormal transcripts were cloned and sequenced.

RESULTS

An unexpected longer product was found in seven patients (11%) by RT-PCR of the FLT3 gene. Sequence analysis of these abnormal products revealed the presence of tandemly duplicated fragments in all seven patients. Three factors were identified to be associated with high incidence of FLT3/ITD; older patients (> or = 10 years) (P = 0.049), high WBC count (> or = 50,000/microl) at presentation (P = 0.002), and M3 in FAB subtypes (P = 0.002). Induction failure was observed in 3 (43%) of 7 patients with FLT3/ITD. Only FLT3/ITD was identified as a significant risk factor for induction failure by univariate analysis (P = 0.013), although it was not significant by multivariate analysis (P = 0.11). The Kaplan-Meier estimate of event-free survival rate at 5 years was 14% for patients with FLT3/ITD, which was significantly lower in comparison with 69% for patients without FLT3/ITD (P = 0.003). This finding was also identified by multivariate analysis (P = 0.01).

CONCLUSIONS

In this study, FLT3/ITD was observed in 11% of childhood AML and identified to be associated with poor prognosis. A large prospective study with uniform treatment is necessary to confirm our results.

Natural antibody against neuroblastoma among Japanese children with or without neuroblastoma

BACKGROUND

This study was conducted to examine the distribution of a natural antibody against neuroblastoma (NB) among Japanese children as well as the clinical significance of the presence of this antibody in the sera during treatment in patients with International Neuroblastoma Staging System Stage 4 NB.

METHODS

Human sera were obtained from 8 healthy volunteers, 82 patients with nonmalignant surgical diseases, and 35 patients with NB including 3 with Stage 1 disease, 6 with Stage 2, 7 with Stage 3, 17 with Stage 4, and 2 with Stage 4S. This natural antibody was quantified by flow cytometry and its antitumor activity was measured by complement-dependent cytotoxicity (CDC) using TGW cells, a human NB cell line, as the target.

RESULTS

Immunoglobulin (Ig) M antibody and CDC activity against NB could be detected in all sera from healthy volunteers and from patients with nonmalignant surgical diseases who were age > 1 year. The amount of IgM antibody and CDC activity in sera from patients with Stage 4 NB at diagnosis consistently was low, most likely because of massive absorption by tumor cells. In this group of patients, the increased CDC activity detected during treatment was indicative of a favorable factor for survival (P < 0.005).

CONCLUSIONS

A natural antibody against NB appears to exist in the sera of Japanese children. The sequential assessment of the levels of this antibody in the sera from Stage 4 NB patients during treatment may serve as a prognostic indicator.

Hemangioblastoma of the third ventricle

A third ventricle tumor, in addition to a recurrent cerebellar hemangioblastoma, was found in a 47-year-old woman on follow-up magnetic resonance imaging (MRI) 5 years after operation of the cerebellar tumor. On MRI, the tumor was hypo- to isointense on T1-weighted images and hyperintense on T2-weighted images compared with the normal gray matter, and was strongly enhanced with gadolinium. The tumor was first treated with fractionated conventional external-beam radiation (5120 cGy in 16 fractions over a 4-week period), resulting in a slight decrease in size of the tumor. For a definite diagnosis and mass reduction, surgery was performed using an interhemispheric translamina terminalis approach, resulting in a partial removal of the tumor due to profuse bleeding. Histological diagnosis was hemangioblastoma. Hemangioblastomas of the third ventricle are extremely rare and have not been specifically discussed. We describe the detailed clinicopathological features of the present case together with the possible explanation for the development of this tumor in this rare location.

[An infant case of sideroblastic anemia that responded to oral pyridoxine]

An 8-month-old boy was admitted because of paleness. Laboratory studies disclosed microcytic and hypochromic anemia: red blood cell count 156 x 10(4)/microliter, hemoglobin 3.5 g/dl, mean cell volume 66 fl, and reticulocytes 0.5/1000. Serum iron was 433 micrograms/dl and exocrine pancreatic dysfunction was not observed. Examination of bone marrow revealed prominent erythroid hyperplasia; 18% of the erythroblasts were distinct ringed sideroblasts. Electron microscopic studies found intramitochondrial iron deposits in the erythroblasts. The patient was given a diagnosis of sideroblastic anemia and responded to oral pyridoxine (50 mg/day) with an immediate increase of reticulocytes to 97/1000, resulting in an improved hemoglobin concentration. He has maintained remission for more than 1 year following discontinuation of pyridoxine, which was administered for 2 months. Congenital sideroblastic anemia is relatively rare and mostly occurs in males, suggesting an X-linked recessive mode of inheritance. Recently, X-linked sideroblastic anemia has been shown to be caused by missense mutations in the delta-aminolevulinic acid synthase (ALAS) gene. A point mutation in exon 5 of the ALAS gene was found in this patient. Iron-deficiency anemia is the most common hematologic disease of infancy and childhood, resulting from lack of sufficient iron for synthesis of hemoglobin. It is therefore mandatory to differentiate sideroblastic anemia from iron-deficiency anemia and other common anemias.

A randomised dose-comparison trial of granisetron in preventing emesis in children with leukaemia receiving emetogenic chemotherapy

This randomised study was performed to assess the anti-emetic efficacy and tolerability of two-dose regimens of granisetron in children with leukaemia. 49 children with leukaemia were treated with three consecutive courses of high-dose methotrexate or cytarabine regimen. During the first course, patients were evaluated regarding the emetogenicity of each regimen. They were randomised in a crossover manner to receive 20 or 40 micrograms/kg of granisetron before the second and third course of chemotherapy. Neither emesis nor severe appetite loss were observed in over 80% of patients within the first 24 h in all treatment groups. There was no significant difference in the anti-emetic efficacy between the two-dose regimens of granisetron. However, complete protection was achieved less frequently on days 2 and 3. Older children and girls appeared to be less well protected. No adverse events attributable to granisetron were observed. Granisetron dose regimens of 20 and 40 micrograms/kg are, comparably, well tolerated and effective in controlling chemotherapy-induced emesis in the first 24 h, though this protection fails thereafter, particularly in older patients and girls.

Treatment of infant acute lymphoblastic leukemia in Japan. Childhood Leukemia Study Group of the Ministry of Health and Welfare (Kouseisho)

Although current chemotherapeutic regimens cure as many as 70% of children with acute lymphoblastic leukemia (ALL), infants continue to show a poor outcome. In this paper, we describe the outcome in 37 ALL infants treated between 1989 and 1995 in Japan. Patients had characteristic findings of infant ALL, including hyperleukocytosis > 100 x 10(9)/l (15/37, 41%), blast cells with a CD10-negative phenotype (30/37, 81%), and 11q23/MLL involvement (21/37, 57%). Seven were treated according to Aggressive Treatment Research Group protocol, 15 according to the Ministry of Health and Welfare protocol, and 15 according to protocols of other institutions. The 3-year overall event-free survival (EFS) was 33%. The EFS was 13% for infants aged < 26 weeks at diagnosis and 43% for infants aged > 26 weeks. Infants who had blast cells with CD10 negative phenotype with 11q23/MLL involvement were also associated with poor prognosis. However, infants with CD10 positive blasts without 11q23/MLL involvement had a better outcome (EFS 75%). These results suggest that intensive chemotherapy is effective for patients with good prognostic factors, but for infants with poor prognostic factors a more aggressive approach such as stem cell transplantation might be necessary.

Alterations of the p53, p21, p16, p15 and RAS genes in childhood T-cell acute lymphoblastic leukemia

We investigated the alterations of the p53, p21, p16, p15 and RAS genes in childhood T-cell acute lymphoblastic leukemia (T-ALL) and T-ALL cell lines by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing. Mutations of the p53 gene were found in three of 57 (5%) patients at diagnosis, one of 14 (7%) patients at relapse and in 12 of 18 (67%) cell lines. In these 12 cell lines, four had more than two mutations of the p53 gene. The p53 mutations were found in four of five cell lines whose original fresh leukemic cells were simultaneously examined original fresh leukemic cells. However, only one of the four fresh leukemic cells had the same mutation. All patients with p53 mutations in the course of disease died. Mutations of the p21 gene were not identified in 71 fresh samples and in 18 cell lines. N-RAS mutations were found in two of 57 (4%) fresh T-ALL patients at diagnosis, and four of 18 cell lines (22%), whereas no mutations were detected in any samples at relapse. Alterations of the p16 gene were found in 18 of 47 (38%) patients at diagnosis and in seven of 14 (50%) at relapse. These differences were not statistically significant. There were no differences in the frequency of alteration of the p16 and p15 genes between event-free patients and the remaining patients. Furthermore, we found the methylation of p16 gene in three of seven patients lacking homozygous deletions, suggesting higher frequency of p16 inactivation than previous reports in T-ALL. Interestingly, we found that one allele is inactivated by methylation and another allele had nonsense mutation in one cell line (KOPT-KI), resulting in loss of protein expression of p16. This type of p16 inactivation has not been so far reported in leukemia. We conclude that, (1) p53 mutations are infrequent at diagnosis but tend to be associated with poor clinical outcome; (2) RAS and p21 mutations may not be involved in the pathogenesis of T-ALL; (3) not only frequent alterations of p16 and p15 genes but also methylation of p16 gene are involved in initiating the leukemogenesis of T-ALLs, and (4) these 5 genes are independently involved in T-ALL.

Veno-occlusive disease of the liver after allogeneic bone marrow transplantation in children with hematologic malignancies: incidence, onset time and risk factors

One hundred and forty children with hematologic malignancies undergoing allogeneic BMT were reviewed in order to clarify the incidence, onset time, and risk factors for veno-occlusive disease (VOD) of the liver. Thirty-eight patients (27.1%) developed VOD diagnosed according to the Seattle clinical criteria. Seventeen patients developed VOD within 20 days of transplantation (early-onset) and in 21 patients developed after day 20 (late-onset) including eight patients with histological confirmation. Late-onset VOD occurred from day 21 to day 508 (median day 39). Moderate or severe VOD developed in 11 early-onset and 13 late-onset patients. Death occurred in eight early-onset and 10 late-onset patients. Serum albumin and cholinesterase levels prior to the start of pretransplant conditioning were significantly lower in early-onset VOD than in late-onset VOD. Multivariate analysis showed that low serum albumin levels (< or =3.7 g/dl) prior to the start of pretransplant conditioning was most strongly associated with the development of VOD. Donor mismatch (other than HLA-matched relatives), use of minocycline, and a long interval (> or =13 months) between diagnosis and BMT were also significantly associated with the development of VOD. In contrast, use of fosfomycin was associated with a decreased risk. Our data suggest that hepatic function reserve is important in the development and onset time of VOD. Veno-occlusive disease of the liver is a complication which may occur a long time after transplantation.

Enhancement of in vitro and in vivo anti-tumor activity of anti-GD2 monoclonal antibody 220-51 against human neuroblastoma by granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor

We have evaluated the anti-tumor effect of anti-GD2 mouse monoclonal antibody (mAb) 220-51 against human neuroblastoma cell line TGW in vitro and in vivo. The mAb 220-51 was able to mediate complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) using human effector cells. In the presence of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte ADCC was significantly augmented in vitro. When mAb 220-51 was administered to tumor-bearing nude mice, tumor growth was significantly inhibited as compared with untreated controls. Administration of recombinant murine GM-CSF in combination with mAb 220-51 significantly enhanced the anti-tumor effect of mAb in vivo. Recombinant human granulocyte colony-stimulating factor (G-CSF) combined with mAb 220-51 was also able to enhance it, although granulocyte ADCC was not affected by the presence of recombinant human G-CSF in vitro. Moreover, GM-CSF and G-CSF work additively to enhance the anti-tumor effect of mAb 220-51 in vivo. The GM-CSF and G-CSF may have a clinical potency in immunotherapy with anti-GD2 mAb for the treatment of neuroblastoma.

Continuous monitoring of blood volume in double filtration plasmapheresis

A continuous hematocrit (HCT) monitor, Crit-Line, was introduced to examine the change in patients' blood volume (BV) due to albumin loss during double filtration plasmapheresis (DFPP) treatments. Nine patients with autoimmune diseases or ABO incompatible renal transplantation received 15 DFPP treatments under Crit-Line monitoring. In these patients, plasma albumin concentration (C(P)) changed from 3.7 +/- 0.6 g/dl to 3.5 +/- 0.5 g/dl and HCT from 28.7% +/- 3.3% to 31.3% +/- 4.3% (change ratio [CR] of BV = -8.1%) during treatment with albumin concentrations (C(S)) of 9.5 +/- 1.0 g/dl and 500 ml volumes (V(S)) of supplementation fluid. Although the apparent CR value of C(P) was -5.3%, on average, the CR of albumin in the patients' plasma (M(P)) was -16.1%, which means a corrected CR value of C(P) by the HCT value to eliminate the influence of the patient's blood volume contraction during treatment. Albumin loss usually occurred in DFPP treatments. The decrease in BV was induced by an oncotic pressure drop due to albumin loss, and often resulted in a blood pressure drop. The amount of albumin loss during DFPP treatments strongly depends on sieving coefficients of the plasma separator (SC(PS)) and the plasma fractionator (SC(PF)), the filtration fraction of the plasma fractionator (FF(PF)), pretreatment C(P) value, and C(S) and V(S) values of the supplementation fluid. To determine the optimum C(S) and V(S) values for each patient, the authors introduced a variable blood volume model for albumin transport in DFPP. In this model, changes in C(P), HCT, and BV values could be estimated during treatment. For example, a patient with an HCT of 31.2%, body weight of 61.1 kg, and pretreatment C(P) of 4.4 g/dl received a DFPP treatment using a plasma separator, OP-05 (SC(PS) of 0.99), and a plasma fractionator, Evaflux 2A (SC(PF) of 0.40), under FF(PF) of 0.8 with a V(S) of 500 ml. A value for C(S) of about 10 g/dl is required for the patient to maintain a normal C(P) level during treatment by an estimation from the model. As a result of the treatment with a C(S) of 10 g/dl, the patient had no adverse reactions, such as a blood pressure decrease, during treatment under these conditions.

Etoposide-related acute promyelocytic leukemia

The development of therapy-related acute myeloid leukemia (t-AML) has become a growing concern over the past decade, because of the increase in the percentage of long-term survivors of primary malignancy. We reviewed 17 cases with etoposide-related acute promyelocytic leukemia (APL) reported in the literature. The close association between treatment with etoposide for Langerhans cell histiocytosis (LCH) and the development of etoposide-related APL was demonstrated among Japanese and Italians. Our data on the breakpoints (b/ps) of the PML and RARalpha genes are presented. It is suggested that chromatin structure might be more important than specific consensus sequence in the distribution of b/ps in etoposide-related APL.

Treatment of hepatoblastoma: less extensive hepatectomy after effective preoperative chemotherapy with cisplatin and adriamycin

BACKGROUND

Although the prognosis of hepatoblastoma was improved by the introduction of cisplatin and doxorubicin (Adriamycin) for adjuvant chemotherapy, extensive hepatectomy continues to be the usual practice. We retrospectively reviewed our recent experience with hepatoblastoma to determine whether the new modality of intensive chemotherapy could change the resectability, extent of hepatectomy, operative complications, and prognosis.

METHODS

The clinical features of 15 children with hepatoblastoma treated between 1985 and 1995 were reviewed. Intensive chemotherapy was added before surgical resection not only when a tumor was unresectable but also when it was large enough to increase the risk of operative morbidity.

RESULTS

There was 100% resectability, and the overall mortality rate was only 6.7%. Fourteen patients have been free of disease for 2 to 12 years. Preoperative chemotherapy enabled resection of six previously unresectable hepatoblastomas. Moreover, hepatic resection tended to be less invasive in several patients whose tumors had been much reduced after preoperative chemotherapy. Intraoperative and postoperative complications were minimal, with a short operative time and small amount of blood loss, especially in the group with delayed primary operation.

CONCLUSIONS

The preoperative administration of cisplatin and Adriamycin reduced the tumor size so that a safe hepatectomy could be performed with less blood loss and minimal technical complications. Unnecessary sacrifice of the normal hepatic tissue was avoided by performing the less extensive hepatectomy.

Prognostic significance of TEL/AML1 fusion transcript in childhood B-precursor acute lymphoblastic leukemia

PURPOSE

A retrospective study was conducted to investigate the prognostic significance of TEL/AML1 fusion resulting from a cryptic t(12;21) in Japanese patients with childhood B-precursor acute lymphoblastic leukemia (ALL).

MATERIALS AND METHODS

Leukemic samples from 144 children with newly diagnosed ALL (104 with CD10-positive B-precursor ALL, 11 with CD10-negative B-precursor ALL, 5 with B-ALL, and 24 with T-ALL) were analyzed by reverse-transcription polymerase chain reaction.

RESULTS

The frequency of patients with TEL/AML1 was 16% (23 of 144) and all patients with TEL/AML1 also had CD10-positive B-precursor ALL. TEL/AML1 was not found in any samples from the patients with T-ALL, B-ALL, or CD10-negative B-precursor ALL. Among patients with CD10-positive B-precursor ALL, age, initial white blood cell count, and immunophenotype did not differ with TEL/AML1 positivity, although the patients were predominantly male (p < 0.01). Clinical outcomes of 94 patients treated with recent protocols were analyzed. Five of the 21 (23.8%) patients with TEL/AML1 relapsed and 4 of these relapsed > 24 months after diagnosis. Although the overall 5-year survival rate was better among patients with TEL/AML1 fusion transcript than among those without it (87.3 +/- 8.7% versus 75.9 +/- 5.8%, respectively), the 5-year disease-free survival (DFS) rates of patients with TEL/AML1 fusion transcript and those without it were similar (64.0 +/- 13.5% versus 69.1 +/- 6.3%, respectively). However, for 57 patients treated with the latest intensive protocol, the 4-year DFS rate was much higher for the patients with TEL/AML1 fusion transcript than for those without it (100.0% v.s. 69.6 +/- 8.4%, respectively, p = 0.1472).

CONCLUSIONS

This study confirmed that TEL/AML1 gene fusion is the most common genetic event in pediatric ALL in Japan and is restricted to CD10-positive B-precursor ALL. Moreover, it was associated with an improved survival rate among patients treated with intensive therapy. Therefore, these data suggest that the patients with TEL/AML1 may not necessarily be candidates for less aggressive treatment.

Treatment of hepatoblastoma: less extensive hepatectomy after effective preoperative chemotherapy with cisplatin and adriamycin

BACKGROUND

Although the prognosis of hepatoblastoma was improved by the introduction of cisplatin and doxorubicin (Adriamycin) for adjuvant chemotherapy, extensive hepatectomy continues to be the usual practice. We retrospectively reviewed our recent experience with hepatoblastoma to determine whether the new modality of intensive chemotherapy could change the resectability, extent of hepatectomy, operative complications, and prognosis.

METHODS

The clinical features of 15 children with hepatoblastoma treated between 1985 and 1995 were reviewed. Intensive chemotherapy was added before surgical resection not only when a tumor was unresectable but also when it was large enough to increase the risk of operative morbidity.

RESULTS

There was 100% resectability, and the overall mortality rate was only 6.7%. Fourteen patients have been free of disease for 2 to 12 years. Preoperative chemotherapy enabled resection of six previously unresectable hepatoblastomas. Moreover, hepatic resection tended to be less invasive in several patients whose tumors had been much reduced after preoperative chemotherapy. Intraoperative and postoperative complications were minimal, with a short operative time and small amount of blood loss, especially in the group with delayed primary operation.

CONCLUSIONS

The preoperative administration of cisplatin and Adriamycin reduced the tumor size so that a safe hepatectomy could be performed with less blood loss and minimal technical complications. Unnecessary sacrifice of the normal hepatic tissue was avoided by performing the less extensive hepatectomy.

Hemolytic uremic syndrome after allogeneic or autologous hematopoietic stem cell transplantation for childhood malignancies

Of 193 children who underwent hematopoietic stem cell transplantation (HSCT) for various malignancies, 10 developed hemolytic uremic syndrome (HUS) 1 1/2-5 months later. All 10 had microangiopathic hemolytic anemia, thrombocytopenia and impaired renal function. Six of 10 presented with pericardial effusion, while three presented with hypertension. No child required plasma exchange, and all patients have survived without life-threatening long-term sequelae. By univariate analysis, the underlying diagnosis of neuroblastoma and a history of cisplatin (CDDP) administration were significantly associated with the development of HUS (P < 0.0001). By multivariate analysis using logistic regression, neuroblastoma and use of total body irradiation (TBI) as a conditioning regimen were significant contributing factors for HUS (P = 0.0001 and 0.036, respectively). Although CDDP administration could not be evaluated because of its strong correlation with the underlying diagnosis, we speculate that CDDP may enhance the nephrotoxicity of TBI, leading to a high incidence of HUS in patients with neuroblastoma.

Calcium-dependent Ret activation by GDNF and neurturin

Glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) define a new family of neurotrophic factors that play crucial roles in survival and differentiation of various neurons. Recent studies demonstrated that GDNF and NTN use a multicomponent receptor system in which glycosyl-phosphatidylinositol (GPI)-linked cell surface proteins and Ret receptor tyrosine kinase function as the ligand-binding and signalling components, respectively. In the present study, we investigated the role of Ca2+ ions for biochemical and biological activities of Ret because Ret has a unique structure of the extracellular domain with the cadherin-like motif. The results demonstrated that Ca2+ ions might be required for the complex formation of Ret and GDNF or NTN that induces Ret oligomerization and autophosphorylation. Full morphological differentiation of neuroblastoma cells by these neurotrophic factors was also Ca2+-dependent. These findings thus suggested that, in addition to GPI-linked cell surface proteins, Ca2+ ions are components of the signal transducing complex formed by Ret and GDNF protein family.