Unrelated donor bone marrow transplantation for 100 pediatric patients: a single institute's experience.

In all, 100 unrelated donor bone marrow transplantations (UD-BMT) were performed in our institute between October 1993 and January 2003. Of 93 evaluable patients, 73 patients had hematological malignancy, 13 had nonmalignancy and seven had lymphoproliferative disease. The estimated 9-year event-free survival (EFS) rate was 57.1+/-5.5% in all patients. In the following analyses of the patients with hematological malignancy, the standard group had significantly better EFS than the high-risk group (61.5+/-7.0 vs 35.6+/-9.7%, P=0.02), and the EFS rate of the tacrolimus (FK-506)+methotrexate (MTX)+/-methylprednisolone prophylactic group for graft-versus-host disease was superior to that of the FK-506 without MTX group (75.7+/-8.0 vs 55.8+/-7.6%, P=0.02). When we compared the EFS rates of the FK506+MTX+/-methylprednisolone (mPSL) group and the HLA-matched related donor BMT group in our institute, these were almost similar (75.7+/-8.1 vs 68.4+/-9.3%). Therefore, UD-BMT using FK-506+MTX+/-mPSL is a safe and useful method for children with hematological malignancy who require allogeneic BMT.

Graft-versus-tumor effect in a patient with advanced neuroblastoma who received HLA haplo-identical bone marrow transplantation.

A 5-year-old boy received CD34-positive HLA haplo-identical bone marrow transplantation from his father as treatment for refractory advanced neuroblastoma. He had residual disease in the para-aortic lymph nodes and multiple bones after the transplant. However, all of his residual disease had disappeared completely 3 years later. He developed grade I acute graft-versus-host disease (GVHD) but had no symptoms of chronic GVHD or any other complications. This case demonstrates the possibility of a graft-versus-tumor effect against neuroblastoma by HLA-mismatched allogeneic hematopoietic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation for 27 children with juvenile myelomonocytic leukemia diagnosed based on the criteria of the International JMML Working Group.

Prognostic factors of juvenile myelomonocytic leukemia (JMML) have not been clarified because of its very low incidence and inaccuracy in the diagnosis. The purpose of this study was to evaluate children with JMML given an allogeneic hematopoietic stem cell transplantation (SCT) and the role of different variables potentially influencing outcome in a nationwide survey in Japan based on the newly proposed criteria by the International JMML Working Group. The study patients were 27 children who underwent SCT among 55 JMML patients retrospectively collected in the survey. The source of grafts was HLA-identical siblings in 12 cases, HLA-matched unrelated individuals in 10 and others in five. Total body irradiation was used in 18 cases. Event-free and overall survival (OS) at 4 years after SCT were 54.2 +/- 11.2% (s.e.) and 57.9 +/- 11.0% (s.e.), respectively. Six patients died of relapse and three of complications. Patients with abnormal karyotypes showed a significantly lower OS than those with normal karyotypes (P < 0.001). Patients below 1 year of age showed a significantly higher OS than those of 1 year of age or more (P = 0.02). Patients with grade 0-1 acute graft-versus-host disease (GVHD) or chronic GVHD had a more favorable OS than those without them, although they were not statistically significant (P > 0.05). Other variables studied were not associated with OS. A multivariate analysis of these factors yielded the abnormal karyotype as the only significant risk factor for lower OS (risk ratio: 11.0; 95% CI: 2.7-45.1).

Intensification of chemotherapy using block therapies as consolidation and reinduction therapies for acute lymphoblastic leukemia during childhood.

Between April 1994 and March 1997, 143 children (age range, 1-15 years) with newly diagnosed acute lymphoblastic leukemia (ALL), except for those patients with t(9;22), were treated according to protocol-94 of the Osaka Childhood Leukemia Study Group. In this trial, the intensity of chemotherapy was enforced in the consolidation and reinduction phases by introducing AML-type block therapies consisting of concentrated administration of 4 to 6 drugs during 5 or 6 days. For patients in the higher risk groups, rotational combination chemotherapy was introduced following the early phase. A total of 124 children with B-cell precursor ALL (B-pre ALL) were classified into 3 groups, the ultrahigh-risk group (UHRG) (15 patients), the high-risk group (HRG) (61 patients), or the standard-risk group (SRG) (48 patients), based on age. leukocyte count, immunophenotype, central nervous system leukemia, response to treatment, and selected chromosomal abnormalities. The complete remission rate was 93%, and the 6-year event-free survival (EFS) rate was 79%+/-4%. EFS rates for the UHRG, HRG, and SRG groups were 67%+/-12%, 80%+/-6%, and 81%+/-6%, respectively. Nineteen patients with T-cell ALL were treated with the protocol for the UHRG. Thirteen patients (68%) attained complete remission, and the 6-year EFS rate was 55%+/-12%. Thus, intensification of chemotherapy improved the EFS rate and AML-type block therapies appeared to be effective as the consolidation and reinduction therapies for B-pre ALL.

Kinetics of plasma cytokines after hematopoietic stem cell transplantation from unrelated donors: the ratio of plasma IL-10/sTNFR level as a potential prognostic marker in severe acute graft-versus-host disease.

The plasma levels of a panel of cytokines and cytokine-associated molecules (IL-1alpha, IL-2, IL-4, IL-6, IL-10, IL-12, IL-15, macrophage colony-stimulating factor (M-CSF), interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), soluble IL-2 receptor (sIL-2R), soluble tumor necrosis factor receptor I or II (sTNFRI or II)) were assessed in 56 plasma samples of 13 pediatric patients undergoing hematopoietic stem cell transplantation (HSCT, bone marrow in 12 and cord blood in one) from unrelated donors. Eight patients developed severe (grade III-IV) acute GVHD (aGVHD). The plasma IL-6, IL-10, M-CSF, sTNFRI and II levels were significantly high in the severe aGVHD group compared to the mild aGVHD group (grade 0-II). The plasma IL-15 level increased transiently in the early period following HSCT and remained high in the severe aGVHD group even after 4 weeks following HSCT. Based on analysis of the correlations between the kinetics of the plasma cytokine levels after HSCT and the clinical manifestations of aGVHD, IL-15 and/or M-CSF were involved in the development of aGVHD, following elevation of the plasma IL-10 and sTNFRI or II levels. These kinetics suggest that IL-10 and sTNFRs worked as suppressor cytokines and seemed to suppress clinical manifestations of aGVHD. Furthermore, it seemed that the plasma ratio of IL-10/sTNFRII from 5 to 12 weeks following HSCT was linked to the poor outcome in the patients with severe aGVHD, suggesting that IL-10 plays an important role in protecting hosts from transplantation-related complications, including GVHD.

Chronic graft-versus-host disease in children and adolescents after bone marrow transplantation from HLA-matched donors.

We analyzed 98 pediatric patients who underwent bone marrow transplantation (BMT) from serologically HLA-matched related donors (RD) or unrelated donors (UD) at our institute to clarify the actual status of chronic graft-versus-host disease (cGVHD). There were 36 evaluable cases of RD-BMT and 35 of UD-BMT. cGVHD was observed in 8 RD-BMT cases (22.2%) and in 23 UD-BMT cases (65.7%). In the RD-BMT cases, the limited and extensive types of cGVHD were observed in 4 cases each, whereas in the UD-BMT cases, the limited type was seen in 11 cases and the extensive type in 12. Prior acute GVHD was observed in 6 RD-BMT cases and in 18 UD-BMT cases. Two RD-BMT patients with extensive type cGVHD died of relapse and cytomegalovirus infection, and 4 UD-BMT patients died because of bronchiolitis obliterans, fungal infection, liver failure, and multiple organ failure, respectively. The incidence of cGVHD in these pediatric patients was as high as that in adult patients when UD-BMT was performed. Some UD-BMT patients required long-term immunosuppressive therapy after BMT. These findings suggest that cGVHD is a serious problem in pediatric UD-BMT. Therefore, intensive prophylaxis and treatment of GVHD must always be performed after UD-BMT.

Successful double autografts for patients with relapsed clear cell sarcoma of the kidney.

Although the prognosis of clear cell sarcoma of the kidney (CCSK) has improved, when metastases occur the probability of cure is very low. We have treated two pediatric patients with relapsed CCSK, one with multiple bone metastases and another with brain metastases. After one or two courses of re-induction chemotherapy and radiation therapy to the sites of metastasis, they received double high-dose chemotherapy with autologous bone marrow rescue. Conditioning regimens were ifosphamide plus melphalan for the first autograft and busulfan plus thiotepa for the second. Hematological recovery was prompt, and no severe complications were observed. They are doing well without evidence of recurrence at 19 and 49 months after the second autograft, respectively.

Rapid disappearance of AML1/ETO fusion transcripts in patients with t(8;21) acute myeloid leukemia following bone marrow transplantation and chemotherapy.

To assess the clinical significance of monitoring minimal residual disease in t(8;21)(q22;q22) AML, RT-PCR assay was conducted during the clinical course of 12 patients who had undergone BMT or conventional chemotherapy. Two cases relapsed after BMT and chimeric RNA was detected soon after BMT in their bone marrow cells. The other three cases, in whom chimeric RNA was not detected after BMT, are in CR at 21 to 33 months following BMT. Similarly, four out of 7 cases who showed negative chimeric RNA after completion of chemotherapy have been in CR at 11 to 34 months following completion of chemotherapy. The present findings appear different from other studies which reported the detection of AML1-ETO chimeric RNA in long-term CR patients.

Changes in hemostatic parameters in hepatic veno-occlusive disease following bone marrow transplantation.

Hepatic veno-occlusive disease (VOD) is a major complication after bone marrow transplantation (BMT). Its prediction, diagnosis and treatment remain unclear. Examination was made of changes in hemostatic parameters in patients with or without VOD after BMT. Twenty-seven children were studied following BMT. Eight of them developed VOD. Tissue plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), thrombomodulin (TM), von Willebrand factor (vWF), factor VII, fibrinogen (FBG), FDP, D-dimer (D-D), plasminogen (PLG), thrombin-antithrombin III (TAT), alpha 2-plasmin inhibitor/plasmin complex (PIC), antithrombin III (AT-III), protein C, N-terminal propeptide for type III procollagen (P-III-P), were measured weekly from pre-BMT to day 28 after BMT. In VOD patients, t-PA and PAI-1 significantly increased (P < 0.05) and FBG significantly fell during the post-transplant period (P < 0.05). Significantly low AT-III and PLG were also noted before VOD (P < 0.05). There were no changes in other hemostatic parameters. t-PA, PAI-1 and FBG would thus appear useful markers for the diagnosis of VOD, and AT-III and PLG, predictive markers for VOD. The coagulation-fibrinolysis system following endothelial cell damage may contribute to the onset of VOD.

Results of single and double autografts for high-risk neuroblastoma patients.

Although intensive therapy with autologous bone marrow transplantation (ABMT) has improved the outcome of advanced neuroblastoma, nearly half the patients with this disease still relapse after a single ABMT. In our previous study, 10 of 22 patients relapsed within 16 months post-transplantation. Predictive risk-factors for relapse were the presence of bone lesions at diagnosis, and a minor response or progressive disease at transplantation. In order to improve the outcome of these high-risk patients, we tested the feasibility of double autografts. To date, eight patients have been treated, and no treatment-related deaths were observed. Six remain in CR or with stable disease for 6 to 29 months. Although more cases and longer observation are needed to draw conclusions, these results are encouraging.

Age-related changes in surface antigens on peripheral lymphocytes of healthy children.

The age-related changes in proportion of various subsets within lymphocytes were investigated in cord blood and peripheral blood from healthy children and adults. The percentages of T and B cells did not show age-related changes, whereas natural killer (NK) cells increased significantly with age. Within lymphocytes or the CD3+ T cell population the proportion of CD45RAbright+ lymphocytes decreased and that of CD45RO+ cells increased, while that of CD45RAdim+ cells showed no age-related change. Within lymphocytes, the percentage of CD45RAbright+ CD4+ cells decreased, together with a decline of that of CD4+ cells. The proportions of CD45RAbright+ CD8+ cells and S6F1bright+ CD8+ cells increased with age, and the age-dependent increase of the proportion of CD8+ cells seems to be mainly attributable to the increases in these subsets. The CD45RAdim+ CD4+ and CD45RAdim+ CD8+ cells co-expressing CD45RO at a low level nevertheless showed no age-related changes. In gamma delta T cells, both delta TCS1+ and delta TCS1- T cells increased with age, but the delta TCS1- gamma delta T cells increased more than the delta TCS1+ subset. Among lymphocytes, the percentages of CD20+, CD21+ and CD22+ cells remained similar, with no age-related changes, but the proportion of CD5+ cells within lymphocytes or B cells decreased. The proportions of CD16+ NK cells among lymphocytes increased with age, and this change was attributable to the increase of CD56+ cells.

CD33+ B-cell precursor acute lymphoblastic leukemia in children: a distinct subgroup of B-cell precursor acute lymphoblastic leukemia.

Clinical and laboratory features associated with CD33 expression were analysed in 123 children with B-precursor acute lymphoblastic leukemia (ALL), including 85 at onset, 34 at relapse and four in a refractory state to induction therapy. CD33 was demonstrated in 13 patients (15.3%) at onset, and it was associated with coexpression of T-cell and multipotential hematopoietic cell-associated antigens, i.e. CD2, CD4 and CD7, which were observed in four of 11 analysed patients (P < 0.01). Patients with CD33 expression were older than those without CD33 (P < 0.01). Although CD33 was the strongest predictor of a poor outcome (event-free survival, 44% for CD33+ and 75% for CD33-patients; P = 0.0041) in univariate analysis, multivariate analysis did not demonstrate significance (P = 0.0645). Fourteen of 38 patients (36.8%) at relapse or in a refractory state showed CD33 expression. Analysis of CD33 expression had also been performed at onset in 16 of these patients and showed acquisition of CD33 in six of 13 patients who had been negative for this antigen at onset. Thus, it seems that CD33+ B-precursor ALL is derived from undifferentiated cells minimally committed to B-cell lineage and more homogeneous than so-called My+ B-precursor ALL with regard to the clinical and biological features. The frequent expression of CD33 on the cells which acquired resistance to chemotherapy may have resulted from expansion of a CD33+ original minor clone or clonal evolution.

Phenotypic characteristics of acute megakaryocytic leukemia and transient abnormal myelopoiesis.

By immunophenotyping and ultrastructural cytochemistry, the disorders involving megakaryocytic lineage cells have been clarified. These disorders are termed acute megakaryocytic leukemia (AMKL) and transient abnormal myelopoiesis (TAM). The characteristics of blasts in these disorders have been extensively investigated from various standpoints including cytochemistry, cytogenetics, ultrastructure and in vitro-colony differentiation. The target cells of AMKL and TAM are immature cells close to stem cells which are capable of differentiating into lineage cells such as megakaryocytes, erythrocytes and myeloid cells. Phenotypically, these blasts frequently express antigens appearing at an early stage in the hematopoietic differentiation pathway. They thus often emerge as mixed phenotypes as seen in mixed lineage leukemia of immature cell origin.

Transient abnormal myelopoiesis in Down's syndrome.

Recent data have elucidated the pathogenesis of transient abnormal myelopoiesis (TAM) to a great extent. TAM is a monoclonal disorder which resolves spontaneously and the target cell in this disorder is a multipotent stem cell which is capable of differentiating into megakaryocytes. The pathogeneses of TAM/AMKL (acute megakaryoblastic leukemia) appears to be closely associated with abnormal quality and quantity of a gene located on chromosome 21. AMKL developing after the regression of TAM appears to come from the same clone as the TAM, which apparently experiences some kind of genetic alterations. It seems that the gene responsible for TAM will soon be cloned in the near future. However, the mechanism of spontaneous regression of TAM has as yet not been clarified. The expanding clone in the transient physiological immunodeficient state, during the perinatal period, might be eliminated with the maturation of more mature immunosurveillance. Alternatively, the TAM clone might be destined to undergo spontaneous death, which is called "programmed cell death" (apoptosis). The mechanism of this phenomenon awaits further elucidation.

Mixed phenotype of blasts in acute megakaryocytic leukaemia and transient abnormal myelopoiesis in Down's syndrome.

Blasts from eight cases with acute megakaryoblastic leukaemia (AMKL) and seven with transient abnormal myelopoiesis in Down's syndrome (TAM) were investigated to clarify their phenotypic characteristics. CD41 and CD7 were the most frequently expressed in both disorders. CD41 was positive in six TAM and five AMKL cases, and CD7 was positive in five TAM and five AMKL cases, respectively. CD33 was detected in four TAM and five AMKL cases. Other myeloid-lineage associated antigens such as CD13 and CD11b could not be found in TAM but were expressed in five AMKL cases. Interestingly, CD56, a neural adhesion molecule, was expressed in three of four TAM and one of five AMKL cases. Cytoplasmic CD3 antigen was also noted in three of five examined cases. A short-term culture study was conducted on blasts from two TAM cases and five AMKL cases. In two cases in which CD41 was not expressed before culture, the expression of CD41 was enhanced after culture with or without 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The expression of CD7 remarkably was depressed, while that of CD13 was enhanced after culture with TPA. These findings suggest that blasts of TAM and AMKL originate from very immature cells and represent a mixed phenotype. In the present study, distinction of phenotypical differences between blast in TAM and AMKL was not possible.

Monocytes appearing repeatedly after chemotherapies had an identical rearrangement pattern of immunoglobulin with leukemic blasts in a patient with CD13+ acute lymphoblastic leukemia.

We recently encountered a patient with acute lymphoblastic leukemia (ALL) who showed temporal monocytosis of an unusually high cell count (5,000-30,000 monocytoid cells/microliter) five times after treatment with different chemotherapies. The leukemic cells expressed B-cell-associated antigens, CD19 and CD10, E-rosette receptor, CD2 and monocyte/myeloid antigen, CD13 simultaneously. They were peroxidase-negative. One week after the initiation of conventional chemotherapy for ALL, the leukemic blasts had disappeared. Alternatively, monocytoid cells appeared along with the recovery from nadir status. They showed several features of monocytes; they were weakly dot-positive for nonspecific esterase, reactive with CD14 and CD13 and Fc gamma-receptor-positive. Furthermore, they migrated into a fungally infected joint space. Features incompatible with normal monocytes were the absence of peroxidase reactivity, the expression of B-cell-associated antigens, CD19 and CD10 and E-rosette receptor, CD2. Southern blot hybridization analysis revealed an unexpected result that HindIII digested DNA from both leukemic blasts and monocytoid cells had the same rearranged band of IgH. Thus, an identical clonality of monocytoid cells, temporally appearing after chemotherapies and leukemic lymphoblasts, was determined in this patient with CD13+ ALL.

Clinical significance of CD7-positive stem cell leukemia. A distinct subtype of mixed lineage leukemia.

Ten leukemia cases with mixed phenotype were investigated in terms of clinical characteristics and cellular origin. Three patients were infants and six patients were older children. Six of them had a high leukocyte count and a mediastinal mass was found in three cases. All but one showed hepatosplenomegaly and/or lymphoadenopathy. In spite of intensive chemotherapy, most of them responded poorly. Cytochemical analysis of their leukemic cells revealed a low percentage of positivity for myeloperoxidase reactivity (less than 25%) in two cases and electron microscopic platelet peroxidase reactivity was found in one of three analyzed cases. Phenotypically, these cells all expressed CD7, and other T-lineage-associated, B-lineage-associated, and/or myeloid-associated antigens were also detected to some extent. In addition, three cases expressed CD41 and one case expressed CD56. The T-cell receptor (TCR) genes and immunoglobulin gene were in the germline configuration in seven cases. In three rearranged cases, two showed only the TCR-delta gene rearrangement, and one had both TCR-gamma and delta gene rearrangements. Cell culture studies with 12-0-tetradecanoyl-phorbol-13-acetate (TPA) revealed differentiation to the T-lineage in two cases and to a myeloid lineage in one case. Megakaryocytic differentiation was detected in two cases in culture without TPA. These results suggest that the cells from these cases arose from stem cells capable of both lymphoid and nonlymphoid differentiation. Although the cells were heterogeneous with regard to their potency of differentiation, they have similar clinical characteristics. Because of poor prognosis, it is important to identify this type of leukemia, and allogenic or autologous bone marrow transplantation should be considered.

Differential usage of delta recombining element and V delta genes during T-cell ontogeny.

We analyzed the usage of the delta recombining element (delta Rec) and six V delta genes in cell samples from 15 patients with CD3- and 10 patients with CD3+ T-cell acute lymphoblastic leukemia in an attempt to define the hierarchy of genetic events that is associated with the T-cell receptor (TCR) alpha/delta gene complex during T-cell ontogeny. Based on the deletion patterns of these genes, we surmised their relative order on chromosome 14 to be as follows: 5'-V delta 4, V delta 6, V delta 1, V delta 5, delta Rec, V delta 2, D delta 1-3, J delta 1-3, C delta, V delta 3-3'. In agreement with previous reports, V delta 1 was found to be preferentially rearranged in CD3+ samples. In CD3- samples, V delta 2 and V delta 3 rearrangements were observed at a high frequency. Incomplete V delta D delta rearrangements using V delta 2 or V delta 3, which are closest to C delta, were observed in three patients with CD3- and one patient with CD3+. These results suggest that V delta 2- and V delta 3-(Dn)D delta 3 recombinations are among the earliest recombinational events. Delta Rec was observed to be rearranged to phi J alpha on one allele. In addition, delta Rec rearrangements to J delta 1 and J alpha close to phi J alpha were also demonstrated on three alleles and one allele, respectively. Delta Rec rearrangements to J delta and J alpha other than phi J alpha also inhibit expression of the TCR delta locus. Approximately half of the alleles with J delta rearrangements showed no involvement of known V delta or delta Rec, indicating the existence of other, yet-uncharacterized V delta or delta Rec-like segments.