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Thrombopoietin (TPO) is a ligand for c-mpl that promotes both proliferation and differentiation of megakaryocytes in vivo and in vitro. We investigated the expression of c-mpl transcripts and the effects of recombinant human TPO (rhTPO) on the proliferation and differentiation of human leukemic cell lines or fresh samples obtained from 32 patients with transient abnormal myelopoiesis (TAM) or acute myeloblastic leukemia (AML). Cells were cultured with TPO alone or combined with rh interleukin-3 (IL-3) or stem cell factor (SCF). Expression of c-mpl was verified in 6 of 13 cases tested. All but one of the cases that showed c-mpl expression responded to TPO. Blasts from all cases of TAM or French-American-British (FAB) subtype M7 showed growth responses to TPO with higher sensitivity than cells of other FAB subtypes and these responses were increased by addition of rhIL-3 or rhSCF in some cases. Responses of cells of other FAB subtypes varied. In addition, increased expression of platelet-specific surface antigens on MO7E cells after incubation with rhTPO was observed. These data suggest that TPO may be involved in the abnormal proliferation and differentiation of human leukemic cells, especially of M7 and TAM cells, considered to be of megakaryocytic lineage.

Recent reports of myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML) developing after treatment with immunosuppressants and granulocyte colony-stimulating factor (G-CSF) has raised the question of whether previously unrecognized myelodysplastic features had been present or whether actual transformation had occurred. We undertook a multi-institutional study of 112 children with aplastic anemia diagnosed between 1976 and 1996 and then treated with immunosuppressants with or without G-CSF. In each case, bone marrow specimens were tested at study entry and every 6 months for 3 years to detect t-MDS/AML as defined by morphologic and molecular/cytogenetic criteria. As of December 2001, all eligible patients had been followed for a median of 3 years. Morphologic abnormalities were found in 17 cases. The patients in 4 of these cases had clonal cytogenetic abnormalities and received MDS diagnoses. The morphologic features of the patients with and without clonal cytogenetic abnormalities were indistinguishable. However, the mast cell content was lower in cases with cytogenetic abnormalities than in cases without them. An elucidation of the role of mast cells may provide information about the differences between aplastic anemia and MDS or about the transition of aplastic anemia to MDS.

To determine useful prognostic factors in treating childhood acute lymphoblastic leukemia (ALL), we correlated conventional risk factors and bone marrow response 14 days after induction chemotherapy. Our study included 116 precursor B-cell (n = 104) and T-cell (n = 12) ALL patients treated with our protocol between 1988 and 1999. The patients were classified into 3 initial risk groups on the basis of conventional risk factors (56 in the low-risk, 33 in the high-risk, and 27 in the very high-risk groups). All patients received similar systemic chemotherapy regimens before the evaluation of their bone marrow on day 14. We evaluated the marrow of 69 patients as M1 (less than 5% blasts), 25 as M2 (5%-25% blasts), and 22 as M3 (more than 25% blasts). Although all patients attained an initial complete remission (CR), relapse was noted in 33 of the 116 patients, and 15 patients died. All of the M1 marrow patients, irrespective of the initial risk group, showed the best event-free survival rate (85.1% +/- 3 4.4%), the lowest relapse rate (14.5%), and the highest attainment of a second CR (100%); they were defined as the new R1 prognostic group. The low-risk patients with M2 or M3 marrow (R2 group) had a relatively high relapse rate, but all of these relapsed patients were treated successfully with subsequent therapy. High- or very high-risk patients with M2 or M3 marrow (R3 group) had the worst prognosis. Our new prognostic definition (R1, R2, R3) incorporating day 14 marrow findings is useful to tailor early-phase treatments for better therapeutic results in childhood ALL.

Hemoglobin (Hb) Bristol-Alesha is caused by a GTG --ATG mutation at codon 67 in the Hb beta chain, resulting in abnormal beta globin chains with mutated molecules from normal beta67 valine (Val) to beta67 methionine (Met) or beta67 aspartate (Asp). We describe a Japanese child with this rare hemoglobinopathy and a very unstable Hb molecule phenotype. The diagnosis of hemolytic anemia was made when the patient was 6 months of age. Development of marked splenomegaly necessitated red blood cell transfusions twice a month. After splenectomy when the patient was 4 years of age, laboratory findings of hemolytic anemia became more prominent. Specific abnormal Hb molecules initially were not detected, and the alpha/beta globin synthesis ratio was abnormal at 2.22. After splenectomy, we identified the presence of abnormal beta-globin chains with a beta67Val:beta67Met:beta67Asp molecule ratio of 74:11:15. We speculate that the high fraction of the beta67Met molecule in this patient, compared with that in previously reported cases, caused extreme Hb instability, which resulted in thalassemic hyperunstable hemoglobinopathy and very severe clinical findings.

Of the several kinds of therapy-related leukemia, therapy-related acute promyelocytic leukemia (t-APL) is most closely associated with topoisomerase II inhibitor administration for treatment of malignancies in adults. Although rare in children, the majority of therapy-related malignancies have been etoposide-related APL associated with Langerhans cell histiocytosis. The authors describe the development of t-APL after chemotherapy administered for non-Hodgkin's lymphoma (NHL) in an 8-year-old girl. One month after cessation of the 3-year chemotherapy regimen of doxorubicin and other agents but not etoposide or radiotherapy, the patient was diagnosed with t-APL with positive PML-RARA molecular abnormality. The patient attained a complete remission following treatment with all-trans retinoic acid-containing chemotherapy. Thereafter, she successfully received hematopoietic stem cell transplantation from an HLA-matched sibling donor. Development of t-APL associated with NHL in children appears to be rare.

The most common nonrandom translocation found among childhood pre-B acute lymphoblastic leukemias (ALL) is t(1;19)(q23;p13), which frequently results in fusion of E2A with PBX1. However, rare cases of childhood ALL and various other hematological diseases with t(1;19) lack the E2A-PBX1 fusion. Analyzing a cell line with pre-B-cell phenotype, TS-2, that carries t(1;19)(q23;p13) but lacks the E2A-PBX1 fusion, we successfully cloned the breakpoints, which fell within introns of MEF2D and DAZAP1. Both chimeric transcripts, MEF2D-DAZAP1 and DAZAP1-MEF2D, whose sequences indicated in-frame fusions between MEF2D and DAZAP1, were expressed in TS-2 cells and in bone-marrow cells of the patient from whom the TS-2 was established. MEF2D-DAZAP1 and DAZAP1-MEF2D proteins were both located in the nucleus, and MEF2D-DAZAP1 was able to form dimers with MEF2D and HDAC4. In addition, exogenous expression of MEF2D-DAZAP1 and DAZAP1-MEF2D promoted the growth of HeLa cells. Given the frequency of t(1;19) without the E2A-PBX1 fusion in hematological malignancies, we suggest that MEF2D / DAZAP1 rearrangements might be involved in the pathogenesis of those diseases.

Background Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH), also known as EBV-associated hemophagocytic syndrome, develops mostly in children and young adults and may be fatal. Early etoposide treatment has been confirmed to be effective in children. However, it is unclear whether the same treatment is useful in adults. Procedure To assess whether etoposide is effective in treating young adult cases, we retrospectively studied the therapeutic measures taken and outcomes in 20 young adult cases of EBV-HLH. Eleven cases were registered in our HLH study center in Kyoto and nine derived from the literature. The patients were between 17 and 33 years old and eight were males. The influence of gender, cell lineage (T- or natural killer-), EBV serology pattern, jaundice and treatment on the outcome was assessed. Results and Conclusions Patients receiving etoposide within four weeks after diagnosis had a good prognosis as five of the seven patients survived compared to one of 13 not treated with etoposide or treated late (chi-square test for survival, P = 0.0095). The Kaplan–Meier analysis showed the 2.5-year survival of 85.7 ± 13.2% in the early etoposide-treated patients, compared to 10.3 ± 9.4% in the remaining patients (log-rank test, P = 0.0141). Thus, early etoposide treatment is effective in treating EBV-HLH in young adults as well as in children. Med Pediatr Oncol 2003;41:103–109. © 2003 Wiley-Liss, Inc.

Perforin gene (PRF1) mutations appear to occur in about 30% of patients with haemophagocytic lymphohistiocytosis (HLH). We tested perforin expression and gene mutations in 14 HLH patients and six patients with Epstein-Barr virus-associated HLH (EBV-HLH) in Japan. Five of the 14 HLH patients had perforin abnormalities. The presence of PRF1 genetic abnormality correlated well with the lack of perforin expression as determined by flow cytometry. Sequencing showed that four patients had a compound heterozygous mutation while the fifth patient had a homozygous mutation. Three of the mutations we detected were novel. In contrast, none of the six EBV-HLH patients showed perforin abnormalities. Our data, combined with the PRF1 mutations in three previously reported Japanese patients, suggest that the 1090-1091delCT and 207delC mutations of the perforin gene are frequently present in Japanese HLH patients (62.5% and 37.5% respectively). Examination of the geographical origins of the ancestors in the perforin-mutant HLH patients revealed that they mostly came from the Western part of Japan, suggesting that the present-day cases may largely derive from a common ancestor.

In this study, we examined a pediatric case of therapy-related myelodysplastic syndrome (tMDS). The symptoms developed 17 months after treatment for acute myeloblastic leukemia (AML, M2 subtype according to the French-American-British [FAB] classification) involving a chromosome abnormality at t(8;21)(q22;q22). Upon diagnosis of tMDS, spectral karyotyping analysis detected a new chromosomal translocation at t(2;8)(p23;p11.2). In addition, fluorescence in situ hybridization analysis suggested a rearrangement in the monocytic leukemia zinc finger (MOZ) gene, located in the 8p11 region of chromosome 8. However, no partner gene on 2p23 could be identified. To our knowledge, this is the first report of tMDS associated with a rearrangement of the MOZ gene. MOZ-linked fusion proteins such as MOZ-CBP (CREB binding protein), MOZ-TIF2 (transcriptional intermediary factor 2), and MOZ-p300 (adenoviral E1A-associated protein) are associated with AML chromosomal abnormalities at t(8;16)(p11;p13), inv(8)(p11q13), and t(8;22)(p11;q13), respectively, and are thought to account for leukemogenesis occurring through the aberrant regulation of histone acetylation. Through a similar mechanism, we believe that MOZ, fused to an unidentified partner gene at 2p23, may have caused an alteration in histone acetylation, resulting in the development of tMDS in this patient.

We studied the effectiveness of risk-directed therapy for infants younger than 13 months of age with acute lymphoblastic leukaemia (ALL). Fifty-five infants were assigned to different treatment programs (from December 1995 to December 1998) on the basis of their MLL gene status at diagnosis. Forty-two cases (76.3%) had a rearranged MLL gene (MLL+) and were treated with remission induction therapy followed by sequential intensive chemotherapy, including multiple genotoxic agents (MLL9601 protocol). Haematopoietic stem cell transplantation (HSCT) was attempted if suitable donors were available. Thirteen infants (23.7%) were classified as MLL- and treated for 2.5 years with intensive chemotherapy for high-risk B-ALL (MLL9602 protocol). Complete remission was induced in 38 of the 42 infants (90.5%) with MLL+ ALL and in all 13 patients (100%) with MLL- disease. In the MLL+ subgroup, the estimated event-free survival (EFS) rate at 3 years post diagnosis was 34.0% +/- 7.5%, compared with 92.3% +/- 7.4% in the MLL- subgroup (overall comparison, P = 0.001 by log-rank analysis). Both age less than 6 months (hazard ratio = 6.87, 95% CI = 0.91-52.3; P = 0.013) and central nervous system (CNS) involvement at diagnosis (hazard ratio = 2.92 95% CI = 1.29-6.63; P = 0.015) were significant independent predictors of an inferior outcome. These findings indicate a strategic advantage in classifying infant ALL as either MLL+ or MLL- early in the clinical course and selecting therapy accordingly. Standard chemotherapy for high-risk B-lineage ALL appeared adequate for MLL- cases. Novel therapeutic initiatives are warranted for infants with MLL+ disease, particularly those with initial CNS leukaemic involvement or age less than 6 months, or both.

A rare association of Epstein-Barr virus-associated T- and B-lymphoproliferative disease (EBV(+) T- and EBV(+) B-LPD) in a patient with WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is reported. A 26-year-old Japanese female, who had been treated for WHIM syndrome since early childhood, developed hemophagocytic syndrome associated with EBV(+) T-LPD at the lymph nodes and spleen. The disease rapidly resolved in response to prednisolone therapy. However, 6 weeks later, fatal EBV(+) B lymphoma unresponsive to chemotherapy occurred in the intestine and other organs. Caution must be exercised that the patient with WHIM syndrome may be at risk for EBV-LPD.

The clinical outcome of childhood aplastic anaemia (AA) with aberrant cytogenetic clones at diagnosis was surveyed. Among 198 children with newly diagnosed AA registered with the AA Committee of the Japanese Society of Paediatric Hematology between 1994 and 1998, cytogenetic studies of bone marrow (BM) cells were completed in 159 patients. Apart from one Robertsonian translocation, seven patients (4.4%) showed clonal chromosomal abnormalities in hypoplastic BM without myelodysplastic features. The patients included six girls and one boy with a median age of 11 years (range 5-14 years). Six patients had del(6), del(5), del(13), del(20), or -7, and one showed add(9). Four patients responded to the first immunosuppressive therapy (IST: cyclosporin A plus anti-thymocyte globulin) and one obtained a spontaneous remission. Cytogenetic abnormalities remained in two patients with an IST response. On the other hand, two patients showed no IST response. One did not respond to repeat IST and died of acute graft-versus-host disease after an unrelated-BM transplant. Another obtained a complete response after a successful BM transplant. No haematological findings at diagnosis predicted the treatment response. No significant morphological changes developed during the course of the illness. A literature review revealed that half of 24 AA patients with chromosomal abnormalities responded to the first IST, and that +6 was the sole predictable marker for IST unresponsiveness. These results suggest that IST can be applied as the initial therapy for AA with cytogenetic abnormalities in the absence of completely matched donors.

The Ikaros (Ik) gene family, which includes Ik, Aiolos (Ai), and Helios (He), is a primary regulator of lymphocyte differentiation, and is involved in the development of acute lymphoblastic leukaemia (ALL). We analysed the expression of the Ik gene family isoforms in 97 ALL cases, consisting of 64 childhood and 33 infant ALL cases, using reverse transcription-polymerase chain reaction (RT-PCR). Expression of Ik was detected in all cases, 87 of which expressed either Ik1 or Ik2, or both, five of which expressed Ik1/Ik2 and Ik6, and another five of which expressed only Ik6. Therefore, the dominant negative isoform of Ik6 was expressed in 10 of the 38 cases of childhood precursor B ALL, but was absent in other types of childhood ALL (26.3%, chi2-test, P = 0.0001). In terms of Aiolos and Helios expression, 49 (65.3%) out of the 75 and 40 (50%) out of the 80 ALL cases tested showed non-spliced Ai1 and He1 respectively. Only one case of T lineage ALL expressed a small-sized isoform of Helios (designated as He6). It was also found that the expression of Ai1 and He1 was low in Ik6-positive patients (Fisher's exact test; Ai1 P = 0.005, Hel P = 0.035).

While studying Ikaros proteins in childhood acute myeloid leukemia (AML), Ikaros isoform 6 (Ik6) expression was detected in 7 of 10 cases of M4 and M5 leukemia, but in none of the remaining French-American-British subtypes (M2, 8 cases; M7, 6 cases). The spliced Ikaros isoforms 4 to 8 (Ik4-8) suppress the function of full-length Ik1 or Ik2 in a dominant-negative manner, owing to their reduced numbers of DNA binding sites. Thus, dominant-negative Ikaros isoforms may inhibit the normal transcriptional regulation of hematopoietic cell development. To clarify the function of Ik6 in developing blood cells, this isoform was transiently transfected into an Ik2+, interleukin-3 (IL-3)–dependent 32D murine myeloid precursor cell line and studied the expression of Bcl-2 family proteins in relation to in vitro cell growth, using a tetracycline-inducible TREx system. The possibility of aberrant cell regulation due to Ikaros functional changes was examined by cotransfecting both Ik2 and Ik6 into Ikaros/Aiolos/Helios triple-negative Cos-7 cells. The results demonstrated IL-3–independent growth by Ik6-transfected 32D clones coincident with up-regulation of the antiapoptotic protein Bcl-XL. Up-regulation of Bcl-XL, but not of other Bcl-2 family proteins, was associated with the suppression of functional Ik2 by Ik6 in a dominant-negative fashion. Thus, the pathogenesis of myelomonocytic/monocytic AML may involve aberrant regulation of apoptosis due to unscheduled expression of the Ik6 isoform.

A 5-month-old boy with X-linked severe combined immunodeficiency (SCID) and aspergillus pneumonia was successfully transplanted. Before and during transplantation, the patient received O2 administration, systemic amphotericin B, and itraconazole. The transplant was performed with a conditioning regimen of busulfan/cyclophosphamide and 2.9 x 10(6)/kg of CD34+ selected bone marrow cells from his HLA haploidentical mother. Acute grade II graft-versus-host disease (GvHD) was well controlled. Neutrophil counts reached >0.5 x 10(9)/L by day 15 and platelet counts reached > 50 x 10(9)/L by day 48. The T-cell subset (counts) in peripheral blood increased to 42.2% (0.31 x 10(9)/L) by day 46. The pneumonia improved by day 54. The patient has been doing well with limited chronic GvHD of the gut with a follow-up of longer than 40 months after BMT. Conquest of aspergillus pneumonia in SCID infants could be achieved by CD34+ bone marrow cell transplantation together with appropriate anti-fungal treatment.

In hepatitis-associated aplastic anaemia (HAA), an immune-mediated mechanism is solely responsible for the development of pancytopenia. We retrospectively analysed the clinical outcome of 61 children with HAA, diagnosed between 1988 and 1996. Of 61 patients, 41 did not receive bone marrow transplantation (BMT) and their survival rate at 7 years was 61.4 +/- 9.3%(+/- SE). Five of these 41 patients developed myelodysplastic syndrome (MDS) or acute myelogenous leukaemia (AML) 7-57 months after the diagnosis of HAA. The incidence of MDS/AML in severe HAA patients who did not receive BMT (n = 30, 27.0 +/- 10.8%) appeared to be similar to that of severe idiopathic AA patients (n = 155, 14.7 +/- 3.7%) treated in the same period.

This study analyzed data on 35 infants with acute myeloid leukemia (AML) who were treated with intensive chemotherapy between 1995 and 1998 in Japan. The incidence of boys, younger age (< 6 months old), and hyperleukocytosis at onset was high in patients with the M4/M5 subtype (n = 23) in the French-American-British classification, compared with the non-M4/M5 subtype (n = 12). Thirteen (56%) and 16 (70%) patients with the M4/M5 subtype also showed 11q23 translocations and MLL gene rearrangements, respectively, whereas only one patient with the non-M4/M5 subtype had this rearrangement. All 35 patients were treated with the ANLL91 protocol consisting of etoposide, high-dose cytarabine, and anthracyclines. Overall survival and the event-free survival (EFS) rates at 3 years of all patients were 76% (95% confidence interval [CI], 61.3%-90.7%) and 72% (95% CI, 56.4%-87.9%), respectively. EFS showed no significant difference between 2 subgroups divided by age, gender, presence of the MLL gene rearrangements, and white blood cell count at onset; EFS in patients with the M4/M5 subtype tended to be better than those with the non-M4/M5 subtype. Although all 6 patients who underwent allogeneic stem cell transplantation (SCT) have been in complete remission, no benefit of SCT was confirmed. These findings suggest that the intensive chemotherapy with the ANLL91 protocol might have been responsible for the observed good outcome of infant AML, even without SCT. The presence of the MLL gene rearrangements or the age at onset had no impact on the outcome of infant AML.

Two cases of cytomegalovirus (CMV) retinitis following bone marrow transplantation (BMT) from unrelated donors are reported. 1 patient had been treated for severe aplastic anemia (SAA) and the other for hypoplastic myelodysplastic syndrome (MDS). Because first line therapy with antithymocyte globulin (ATG) and cyclosporin A (CsA) had failed, BMT was performed following a conditioning regimen of ATG, cyclophosphamide, and total lymphoid irradiation. Treatment for CMV retinitis was successfully carried out with gancyclovir (systemic and intraocular injection), foscarnet, and photocoagulation (Case 1) and gancyclovir and foscarnet (Case 2). Both patients also developed Epstein-Barr virus-associated lymphoproliferative disease (EBV-LPD). We compared these 2 cases with 14 SAA patients who did not develop CMV retinitis after BMT using marrow from either HLA-identical siblings (n = 9) or from unrelated donors (n = 5). Unlike the retinitis patients, the latter 5 patients received ATG only once. The retinitis patients had significantly lower CD4+ T-cell levels in their peripheral blood than the 14 patients who did not develop CMV retinitis. We believe that repeated treatment with ATG and transplantation from unrelated donors may lead to immune dysfunction that could increase the likelihood of CMV retinitis, as well as LPD. For such BMT patients, regular ophthalmic examinations and careful testing for CMV antigenemia are recommended.

We report a retrospective analysis of children with myelodysplastic syndrome (MDS) diagnosed between 1990 and 1997 in Japan. In total, 189 patients were enrolled: 122 cases of primary MDS (26 RA, 18 RAEB, 25 RAEBt, 53 CMML/JMML), 24 cases with constitutional predisposition to MDS, and 43 cases of therapy-related MDS (t-MDS). The frequency of pediatric MDS was estimated to be 7.7% of all leukemias. Cytogenetic abnormalities were observed in 41% of primary MDS and 90% of t-MDS cases. The 4-year survival rate, estimated by Kaplan-Meier analysis, for primary RA was 78.9%, while other types of MDS and JMML had rates lower than 40%, and t-MDS showed an even more unfavorable prognosis. In primary MDS, the survival rate of patients with cytogenetic abnormalities was significantly lower. Among prognostic variables by IPSS, only the cytogenetic pattern was useful for predicting outcome in childhood MDS. There was no apparent advantage to chemotherapy for RA, and the survival rate in patients with primary RA, JMML, or t-MDS receiving stem cell transplantation was significantly higher. More precise designs of our diagnostic and classification systems, as well as therapeutic trials in large-scale prospective studies, are necessary for further improvements in MDS outcome.

Over the past two decades, the underlying pathophysiology of haemophagocytic lymphohistiocytosis (HLH) (synonyms: haemophagocytic syndrome, macrophage activation syndrome) has been well recognised. Cytokine storm plays a major role, which derives from an inappropriate immune reaction caused by proliferating and activated T-cell or natural killer (NK) cells associated with macrophage activation and inadequate apoptosis of immunogenic cells. Many biological parameters reflecting activity of disease or response to treatment have been identified, in particular, serum ferritin has been confirmed to be one of the markers for HLH. The common types of HLH consist of non-hereditary (acquired) infection-associated disease such as Epstein-Barr virus (EBV)-haemophagocytic lymphohistiocytosis (HLH) and hereditary (familial) disease such as FHL, in which, at the molecular level, dysfunctional perforin was clarified. Regarding the therapeutic strategies, prompt differential diagnosis of underlying disease is essential and choice of treatment should be based on the risk (low or high) of prognosis, where either cyclosporin A, steroids or iv. immunoglobulin (IVIG) may be indicated as initial treatment for low-risk patients, with etoposide-containing regimens for high-risk patients. Significant improvement of prognosis has been obtained by incorporating intensive supportive care at the disease onset and prompt introduction of immunosuppressants to control cytokine storm. Subsequent immunochemotherapy and haemopoietic stem cell transplantation have contributed significantly to further improve survival of hereditary and refractory HLH patients.

We performed the immunophenotyping of 101 patients with B-cell non-Hodgkin's lymphoma (B-NHL) using two-colour flow cytometry (FCM) and found that lymphoma cells coexpressed at least one kind of T-cell-associated antigen (T-Ag; CD2, CD5, CD7) in 25 patients (24. 8%). Among these three T-Ags, CD5 was the most frequently expressed, in 21 patients (20.8%), followed by CD7, expressed in five patients (5.0%), and CD2, which was expressed in two patients (2.0%). Two kinds of T-Ag were simultaneusly expressed in three patients (CD2/CD5, CD2/CD7, and CD5/CD7, each expressed in one patient). Concerning the expression pattern of T-Ag, there were no significant differences between lymph nodes and extranodal organs in the three patients with T-Ag-positive B-NHL (T-Ag(+) B-NHL) who were analysed. When comparing the clinical features between T-Ag(+) B-NHL and T-Ag-negative B-NHL (T-Ag(-) B-NHL), extranodal involvement and higher International Prognostic Index (H and H.I.) were significantly frequent in the former subgroup (P = 0.0119 and P = 0. 0302 respectively).

The pathogenesis of haemophagocytic lymphohistiocytosis (HLH) in children without a known familial pattern of inheritance is often difficult to establish. Splenic enlargement, one of the main clinical findings in this disorder, has led to the use of splenectomy for uncontrollable coagulopathy, persistent cytopenia or both. This procedure is also thought to be a useful tool in making a differential diagnosis in cases of the immunochemotherapy-resistant HLH. We report here five cases of splenectomized childhood HLH, in which subsets of mononuclear spleen cells were analysed either by flow cytometry or immunohistochemistry, and the results were compared with those from cases of hereditary spherocytosis (controls). There was a statistically significant depletion of CD19+ B cells in the HLH cases (3.8 ± 3.2% vs. 52.6 ± 4.5%, P

FK506-related leukoencephalopathy has been reported to be reversible and readily treated by discontinuation or reduction of FK506. We describe two pediatric cases of FK506-related leukoencephalopathy following allogeneic bone marrow transplantation, which could not be readily controlled. These cases show that FK506-related leukoencephalopathy is not always reversible, and patients may develop epilepsy. Bone Marrow Transplantation (2000) 25, 331-334.

Latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) is considered to be an oncoprotein because it is crucial for B-lymphocyte transformation. Since a 30 base pair (bp) deletion in the carboxy-terminal portion of the LMP1 gene was found in a CAO cell line derived from nasopharyngeal carcinoma containing EBV, an association between EB viral genetic alteration and tumorigenicity has been postulated. In this study we have analyzed LMP1 DNA isolated from 10 Japanese patients with EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH). In all HLH patients, we found the 30 bp deletion and 4-8-tandem repeats of the sequence DNGPQDPDNTD in the LMP1 gene. Furthermore, detailed amino acid (aa) sequence analysis revealed that 7 aa substitutions identical to those found in CAO-LMP1 but not in B95.8 cell line-LMP1 were found in all the HLH cases. NF-kappaB assay revealed that HLH-LMP1 activated NF-kappaB significantly more than that of B95.8-LMP1 (p=0.032). We conclude that EBV from all of our HLH cases shared common genetic characteristics with EBV obtained from the CAO cell line, which is distinct from the wild-type EBV isolated from the B95.8 cell line. These data suggest that the mutational changes of the LMP1 gene may play an important role in the pathogenesis of these fatal EBV-related disorders.

We report A case of Sjögren's syndrome complicated with MALT (mucosa-associated lymphoid tissue lymphoma) in childhood. Additionally, Helicobacter pylori infection into the gastric mucosa was highly suspected in this case. A 13-year-old girl suffering from multiple joint pain had received treatment as Juvenile Rheumatic Arthritis with no clinical improvement until introduction to our hospital. On admission to our hospital, high levels of serum anti-SSA and anti-SSB (80.2 and 16.1 holds, respectively) were detected. Minor salivary gland biopsy showed a typical histological finding for Sjögren's syndrome as infiltrating lymphocytes around the excretory ducts. Computed tomography and 67Gallium scintigraphy showed a gastric tumor, and it was diagnosed as primary gastric B-cell MALT lymphoma by the histopathological findings. Additionally, Helicobacter pylori infection into the gastric mucosa was highly suspected. Recently it is emphasized that infection of Helicobacter pylori is related with gastric MALT lymphoma. There has been no reports of children who have Sjögren's syndrome associated with malignant lymphoma. Taken together, Helicobacter pylori infection superimposed with Sjögren's syndrome might accelerate clinical course in our particular case.

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, immunodeficiency and eczema. X-linked thrombocytopenia (XLT) is a mild form of WAS with isolated thrombocytopenia. Both phenotypes are caused by mutation of the Wiskott-Aldrich syndrome protein (WASP) gene. In this study we investigated the role of WASP in the differentiation of CD34-positive (CD34+) cells isolated from the bone marrow of patients with WAS (n = 5) or with XLT (n = 4). Megakaryocyte colony formation was significantly decreased in patients with WAS when compared with normal controls. The formation of granulocyte-macrophage colonies and erythroid bursts were also decreased in WAS patinets. In contrast, in XLT patients, formation of all these colonies was normal. However, in vitro proplatelet formation of megakaryocytes induced by thrombopoietin was markedly decreased in both XLT and WAS. Electron microscopic examination revealed that megakaryocytes obtained from WAS or XLT patients grown in vitro had abnormal morphologic features, which seemed to be caused by defective actin cytoskeletal organization, including labyrinth-like structures of the demarcation membrane system and deviated distribution of the alpha-granules and demarcation membrane system. These observations indicate that WASP is involved in the proliferation and differentiation of CD34+ haemopoietic progenitor cells probably by its participation in signal transduction and in the regulation of the cytoskeleton.

The current status of hemophagocytic lymphohistiocytosis (HLH) in infants and children has been studied.Eighty-two cases of pediatric HLH, for which there was no confirmed familial inheritance, were comparatively studied between 36 patients less than 2 years of age and 46 patients more than 2 years of age.In all cases, persistent fever, cytopenia, liver dysfunction, and hepatosplenomegaly were the most frequently noted symptoms. Hyperferritinemia (1000 micrograms/L) and elevated blood levels of lactate dehydrogenase (1000 IU/L) were observed in 90% and 89.7%, respectively. These figures were considerably higher than for either hypertriglyceridemia (2 mmol/L) (50%) or hypofibrinogenemia (1.5 gm/L) (57.4%), indicating that increased serum ferritin and lactate dehydrogenase concentrations might be good diagnostic parameters for HLH. These parameters are nonspecific but are of follow-up and prognostic value in these HLH cases. No differences were found in clinical signs and symptoms or other laboratory findings for the two age groups. Immunochemotherapy was administered in the similar regimens to patients in both groups. Of the 82 patients, 13 (15.9%) succumbed to a fatal course within 2 months after diagnosis, and Kaplan-Meir analysis for all cases predicted the overall disease-free patient survival at 4 years from the onset of disease to be 57.2% (95% confidence interval (CI), 45.1% to 69.3%). There was a slightly, but not statistically significant, poorer prognosis for the younger patients: 44.2% (95% CI, 26.0% to 62.4%) survival for the infant group versus 67.2% (95% CI, 51.8% to 82.6%) survival for the older group (p = 0.0569).Refinement of the treatment is mandatory to improve the outcome of HLH in both infants and older pediatric patients.

Clinical features in patients with haemophagocytic lymphohistiocytosis (HLH) have been demonstrated to be characterized by hypercytokinaemia. Previously, we reported the impact of high serum levels of interferon (IFN)-gamma and soluble IL-2 receptor (sIL-2R) on patient outcome; however, it was not known if serum levels of interleukin (IL)-6 also could be a prognostic factor. In a study during the active phase of disease in 25 cases of HLH in children and young adults (median age 3 years, range 0.1-23 years), we noted 12 cases which showed serum IL-6100 (normal4.0) pg/ml. Five of these cases showed hyper-IL-6-naemia alone without hyper-IFN-gamma-naemia (group A) whereas seven cases showed both hyper-IL-6- and IFN-gamma-naemia (group B). Patient outcome did not differ between the patients with IL-6100 pg/ml and those with IL-6100 pg/ml, suggesting that high serum concentrations of IL-6 alone do not necessarily indicate poor prognosis in patients with HLH. Among the cases with hyper-IL-6-naemia (100 pg/ml), underlying disorders causing haemophagocytosis were found to be different between groups A and B.

BACKGROUND Previous reports suggesting a correlation between lymphoproliferative disease and serum levels of beta-2-microglobulin (beta-2M) and in vitro data indicating a role of cytokines in the production of beta-2M prompted a study of serum and urine beta-2M concentration in patients with hemophagocytic syndrome (HPS), because no data were previously available for HPS, a pathologic state associated with excessive cytokines secreted from activated reactive/malignant lymphocytes and histiocytes. METHODS Serum and urine beta-2M levels were measured in six children with HPS during active and convalescent phase and in other diseases. RESULTS Serum and urine beta-2M levels during active phase HPS were significantly high not only in serum (median, 7.5 mg/l; range, 2.3-16.0 mg/l; P 31,650 micrograms/gram Creatinine (gCr); range, 8179-236,333 micrograms/gCr; P < 0.01), compared with levels during convalescent phase HPS (median, 2.0 mg/l; range, 0.9-2.5 mg/l in serum and median, 338 micrograms/gCr; range, 223-585 micrograms/gCr in urine) and in control subjects with diseases such as acute lymphocytic leukemia (median, 2.3 mg/l; range, 1.0-2.8 mg/l in serum and median, 327 micrograms/gCr; range, 48-2684 micrograms/gCr in urine), infectious mononucleosis (median, 2.9 mg/l; range, 2.5-5.5 mg/l in serum and median, 348 micrograms/gCr; range, 80-1325 micrograms/gCr in urine), and Kawasaki disease (median, 2.8 mg/l; range, 1.5-3.3 mg/l in serum and median, 1016 micrograms/gCr; range, 214-4500 micrograms/gCr in urine). Noteworthy was the observation that urine beta-2M levels correlated closely with HPS disease activity. CONCLUSIONS Urine beta-2M appears to be a useful marker for assessing disease activity in patients with HPS.

Summary. We studied the expression of HoxA9 and Meis1 by reverse transcriptase-polymerase chain reaction analysis in leukaemic cells from cases of infant acute lymphoblastic leukaemia (ALL, n = 27) and childhood ALL (n = 29). These two genes were co-expressed significantly more frequently in infant ALL than in childhood ALL (19/27 vs0/29 cases, P

Activated ras genes are often associated with human myeloid leukemias with a monocytic differentiated phenotype. To investigate the role of the activated ras gene in leukemogenesis, a myeloid nontumorigenic cell line (FDC-P1) was infected with a selectable retroviral vector carrying the v-Ha-ras gene (H1neo). Infected FDC-P1 cells were not only tumorigenic, but also showed increased monocytic differentiation in vitro. Monocytic differentiation and tumorigenicity in vivo were correlated with several-fold increased levels of activated ras gene expression. Tumorigenic cells were arrested with respect to monocytic marker expression at a much later stage of macrophage differentiation than the parental noninfected FDC-P1 cells. These data thus suggest a model of how activated ras genes could be involved in the preferential induction of hematopoietic malignancies with a myelomonocytic phenotype.

The hemophagocytic lymphohistiocytoses (HLH) comprise a heterogeneous group of disorders characterized by dysregulated activation of T cells and macrophages. Although some patients with HLH harbor perforin gene mutations, the cause of the remaining cases is not known. The phenotype of HLH bears a strong resemblance to X-linked lymphoproliferative disease (XLP), an Epstein-Barr virus (EBV)-associated immunodeficiency resulting from defects in SH2D1A, a small SH2 domain-containing protein expressed in T lymphocytes and natural killer cells. Here it is shown that 4 of 25 male patients with HLH who were examined harbored germline SH2D1A mutations. Among these 4 patients, only 2 had family histories consistent with XLP. On the basis of these findings, it is suggested that all male patients with EBV-associated hemophagocytosis be screened for mutations in SH2D1A. Patients identified as having XLP should undergo genetic counseling, and be followed long-term for development of lymphoma and hypogammaglobulinemia.

CD7 antigen was found to be expressed on malignant mesothelioma arising from the right pleura in a 15-year-old girl not only by immunostaining using monoclonal antibodies, but also by Northern blot analysis. The level of expression in this tumor was comparable to those in T-cell lines, Jurkat and CCRF-CEM. Cytogenetic analysis of the tumor showed hypodiploidy (n = 43). CD7 has been regarded as one of the hematopoietic cell markers selectively expressed on the majority of T cells and multipotential stem cells. To our knowledge, this is the first report of a non-hematopoietic tumor expressing CD7.

A 28-month-old girl with acute lymphoblastic leukemia (ALL) showing a t(4;11)(q21;q23) karyotype successfully underwent allogeneic bone marrow transplantation (BMT) at relapse. The chimeric MLL-AF4 message on her bone marrow (BM) specimens, examined by reverse transcriptase-polymerase chain reaction, was detectable at diagnosis, relapse, and just before BMT but became undetectable following BMT. She has since maintained complete remission. This observation suggests that detection of the chimeric message in BM may be useful to predict clinical outcome in patients with t(4;11) ALL.

Fourteen patients with stage III–IV neuroblastoma were treated with alternating combination chemotherapy consisting of (a) VP16/cisplatin and (b) doxorubicin/vincristine/cyclophosphamide. The initial response to induction chemotherapy, especially to VP16/cisplatin was evaluated by determining t 1/2 for urinary vanillylmandelic acid (VMA), homovanillic acid and serum neuron specific enolase (NSE). The period prior to normalization of these parameters was also determined. The patients could be classified as 7 rapid responders, with less than 3 weeks oft 1/2 VMA, or t 1/2 NSE, and 7 slow responders longer than 4 weeks of t 1/2 VMA. An analysis of the data indicates that an initial rapid response correlated with subsequent high complete response rate, but did not necessarily predict better prognosis in these patients.

Ikaros is an essential regulator of lymphocyte differentiation. Mice transgenic for the Ikaros dominant negative (DN) mutation rapidly develop lymphoid malignancies. Various human leukemias have also been reported to express Ikaros DN isoforms, but its role in leukemogenesis is yet to be defined. We demonstrate that overexpressed Ikaros DN (Ik6) prolonged the survival of two different murine pro-B cell lines in cytokine deprived condition, and this was associated with increased expression of Bcl-xl. A survey of the upstream controller(s) of Bcl-xl expression revealed Ik6 overexpression enhanced the phosphorylation of JAK2 and STAT5. Interestingly, the Ik6 expressing cell lines showed reduced expression of B-cell differentiation surface marker CD45R (B220), which is also known as a JAK2 inhibitor. Although further evaluation with human clinical materials are required, these results propose a putative role of Ik6 in the development of B-lineage acute lymphoblastic leukemia, by activating the JAK2-STAT5 pathway and thus stimulating the production of Bcl-xl.

A 21-year-old woman developed immune thrombocytopenia (ITP), subclinical Graves disease and peripheral neuropathy without typical chronic graft-versus-host disease (GVHD) 5 years following an allogeneic bone marrow transplantation from an HLA-identical sibling. She received high-dose intravenous immunoglobulin (IVIG) and prednisolone (PSL), which resulted in transient recovery of platelet numbers and muscle weakness. A combination of cyclosporine and PSL induced a durable response against not only the thrombocytopenia but also her high levels of thyroid stimulating antibody (TSAb), muscle weakness and sensory abnormality. The level of thyroglobulin in the donor, who had not developed Graves disease, was also elevated, indicating that late onset-subclinical Graves disease was caused by donor lymphocytes that were autoreactive to the thyroid glands.

The prognosis of patients with acute lymphoblastic leukemia (ALL) and central nervous system (CNS) relapse has historically been very poor. Although chemo-radiotherapy has improved outcomes, some patients still have a poor prognosis after CNS relapse. Therefore, allogeneic hematopoietic stem cell transplantation (allo-SCT) has recently become an option for treatment of CNS leukemia; however, information, particularly on the long-term outcome of transplant recipients, is limited. We performed allo-SCT in eight pediatric patients with ALL (n=7) or T-cell type non-Hodgkin's lymphoma (n=1), who had isolated CNS relapse. All patients survived for a median of 70.5 (range, 13-153) months after SCT. Sequelae developed late in some patients: mental retardation (IQ=47) in one patient, severe alopecia in two patients, limited chronic graft-versus-host-disease in three patients, and amenorrhea and/or hypothyroidism in three patients. Except for a pre-school child with post transplant CNS relapse, six out of seven patients show normal school/social performance. Our results clearly indicate a high cure rate of isolated CNS relapse by allo-SCT in pediatric lymphoid malignancies; however, there needs to be further studies to determine which are the appropriate candidates for transplantation and what is the best transplant regimen to achieve high cure rate and maintain good quality of life.

We report here the first case with Diamond-Blackfan anemia (DBA) who responded to rituximab. The patient is an 8-yr-old Japanese girl with refractory DBA accompanied by complex congenital heart disease. She received two doses of rituximab, 375 mg/m(2)/wk. She became transfusion independent 6 months after the treatment without any serious side effect. However, after 8 months of transfusion-free period, her condition returned to the pretreatment level with recovery of peripheral B cells. Rituximab may be a successful therapy for refractory DBA where B cells play a crucial role in the pathogenesis of the severe anemia.

A young female patient in a second remission of acute lymphoblastic leukemia underwent bone marrow transplantation after total body irradiation and high-dose cytarabine from her HLA-matched brother. Following successful engraftment, mixed chimerism was seen 75 days post transplant. The karyotype contained numerous abnormalities in residual recipient cells. Chromosomes 1, 7, 13, and X were significantly more affected than other chromosomes. The high-frequency breakpoints identified were 1p22.2, 5q31.2, and 13q14.2. Some karyotypes specific for leukemia, such as t(9;22)(q34.1;q11.2) and t(8;21)(q22.2;q22.2), not seen with the original disease, were also present. As the frequency of aberrant chromosomes increased markedly with time, donor leukocytes were infused 14 months after BMT, which effectively eradicated the abnormal karyotypes.

Secondary lymphoid malignancy, particularly acute lymphoblastic leukemia (ALL), is rare. We report one case of ALL and another case of mediastinal lymphoblastic lymphoma developed after treatment for neuroblastoma. The secondary ALL characterized by short latency period and an 11q23 translocation apparently was induced by etoposide treatment. The pathogenesis of the secondary lymphoma is less certain and may be related to previous treatment with cyclophosphamide and radiotherapy, host susceptibility, or chance occurrence. One child died of progressive lymphoma and the other remains in remission 1 year following allogeneic bone marrow transplantation. Additional studies are needed to determine the risk, pathogenesis, and optimal treatment for secondary lymphoid malignancy.

The occurrence of adenopathy in patients with myelodysplastic syndrome-associated extramedullary myeloid cell tumors has rarely been reported. We describe a 7-year-old girl with juvenile myelomonocytic leukemia who showed the novel chromosomal abnormality t(9;12)(p22;q24.1) and who developed severe adenopathy of the cervical lymph nodes, tonsils, and adenoids that was manifested as granulocytic sarcoma. Following chemotherapy, the patient underwent a conditioning regimen of busulfan, cyclophosphamide, and total body irradiation followed by successful allogeneic bone marrow transplantation from her single HLA locus-mismatched mother at 6 months after her diagnosis. The patient continues to be well and in remission 3 years after stem cell transplantation.

Although immunochemotherapy has been reported to be an effective initial treatment for patients with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH), the long-term outcome of these patients remains unknown. The main purpose of this study was to determine the outcome of the EBV-HLH patients treated between 1992 and 2001.During this period, a total of 78 EBV-HLH patients were consecutively registered in 3 separate studies. The rates of initial response, reactivation, and survival as well as causes of death were analyzed. The outcome of the patients who received hematopoietic stem cell transplantation was also studied.With a median follow-up of 43 months, clinical reactivation was noted in 13 patients (19.4%) and a total of 12 patients needed hematopoietic stem cell transplantation, of whom 9 are alive and well. There had been 19 deaths: early deaths were due to hemorrhages and infections (n=11), while late deaths were related to late reactivation (n=4), transplant-associated causes (n=3) and secondary leukemia (n=1). Overall, after a median follow-up of 43 months, 59 (75.6%) of the 78 patients are alive and well.The majority of successfully treated EBV-HLH patients have a good outcome and remain disease-free.

Based on recent fetomaternal microchimerism/tolerance theory, two children with acute lymphoblastic leukemia underwent non-T-cell-depleted hematopoietic stem cell transplants (SCT) from haploidentical HLA 2 loci-mismatched family donors (one from a sibling, one from the mother). Engraftment was achieved in two patients. In two recipients, acute graft-versus-host disease was limited to grade II or less, and no chronic graft-versus-host disease developed. Both of these patients have maintained complete remission for more than 8 months post-SCT. Non-T-cell-depleted SCT from haploidentical HLA 2 loci-mismatched family donors seems feasible if microchimerism is detectable.