Atsushi Makimoto

Comparative study of FDG PET/CT and conventional imaging in the staging of rhabdomyosarcoma

ObjectiveThe current study was conducted to compare the diagnostic accuracy between 18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT), and conventional imaging (CI) for the staging and re-staging of patients with rhabdomyosarcomas.MethodsThirty-five patients who underwent FDG PET/CT prior to treatment were evaluated retrospectively. CI methods consisted of 99mTc-hydroxymethylene diphosphonate bone scintigraphy, chest radiograph, whole body CT, and magnetic resonance imaging of the primary site. The images were reviewed and two boardcertified radiologists reached a diagnostic consensus. Tumor stage was confirmed by histological examination and/or follow-up examinations.ResultsInterpretation on the basis of FDG PET/CT, and CI, diagnostic accuracies of the T and N stages were similar. Using FDG PET/CT, the M stage was correctly assigned in 31 patients (89%), whereas the accuracy of CI in M stage was 63%. TNM stage was correctly assessed with FDG PET/CT in 30 of 35 patients (86%) and with CI in 19 of 35 patients (54%). The overall TNM staging and M staging accuracies of FDG PET/CT were significantly higher than that of CI (P < 0.01).ConclusionsFDG PET/CT is more accurate than CI regarding clinical staging and re-staging of patients with rhabdomyosarcomas.

Response-oriented preemptive therapy against cytomegalovirus disease with low-dose ganciclovir : a prospective evaluation

BACKGROUND Preemptive therapy against cytomegalovirus (CMV) disease has succeeded in reducing the incidence of CMV disease, but the toxicity of ganciclovir remains problematic. METHODS We prospectively evaluated the efficacy and toxicity of a preemptive protocol with ganciclovir at a reduced initial dose in 40 patients who achieved engraftment after allogeneic hematopoietic stem cell transplantation. RESULTS Twenty-three (58%) patients had high-risk features, including transplant from an HLA-mismatched or unrelated donor, or associated acute graft-versus-host disease. CMV antigenemia assay was performed weekly, and ganciclovir was started in a risk-adapted manner, in which the initial dose of ganciclovir was fixed at 5 mg/kg/d and then adjusted based on the results of a weekly CMV antigenemia assay. In this protocol, 23 (58%) patients demonstrated positive antigenemia, and 19 (48%) received a preemptive administration of ganciclovir. Only one patient had CMV disease in the gastrointestinal system, which was successfully treated with a regular therapeutic dose of ganciclovir. Consequently, the total dose of ganciclovir was significantly less than that in a previous protocol using the conventional double dose (5 mg/kg twice daily) of ganciclovir (134 mg/kg vs. 190 mg/kg on average, P=0.046). There were no significant toxicities attributed to ganciclovir, except for neutropenia <0.5 x 109/L, which developed in three patients for 3, 4, and 14 days, respectively, with granulocyte colony-stimulating factor support. CONCLUSION Preemptive therapy with a low initial dose of ganciclovir appeared to be effective even in high-risk patients. Further randomized controlled trial is warranted.

The Role of PGE2 in the Differentiation of Dendritic Cells: How Do Dendritic Cells Influence T‐Cell Polarization and Chemokine Receptor Expression?

The role of prostaglandin E2 (PGE2) in the function of dendritic cells (DCs), T‐cell polarization, and expression of chemokine receptors was evaluated in human cells. Immature DCs were generated from peripheral blood CD14+ cells using a combination of GM‐CSF and interleukin‐4 (IL‐4) with or without PGE2. On day 6, maturation of DCs was induced by the addition of tumor necrosis factor alpha with or without PGE2. DCs harvested on day 6 (immature DCs) or day 9 (mature DCs) were examined using functional assays. In the presence of PGE2, immature and mature DCs showed, phenotypically, a lower expression of CD1a and, functionally, a higher allostimulatory capacity at a high DC/T‐cell ratio than control cells cultured in the absence of PGE2. DCs cultured in the presence of PGE2 induced the differentiation of naïve T cells toward a helper T‐cell type 1 (Th1) response, which was independent of IL‐12 secretion in the basal state despite a slightly lower interferon gamma secretion compared with control cells. However, the function of cytotoxicity‐stimulating autologous T cells was not augmented by the addition of PGE2. Immature DCs expressed the inflammatory chemokine receptors, CCR1 and CXCR4, but not CCR6, regardless of the presence or absence of PGE2. Mature DCs expressed CCR7 equally, measured using a migration test and the measurement of calcium flux with macrophage inflammatory protein‐3β and reverse transcription‐polymerase chain reaction assay in all of the groups. All of these findings suggest that PGE2 affects the DC‐promoted differentiation of naïve T cells to a Th1 response in the basal state, without affecting chemokine receptor expression on DCs.

Antithymocyte globulin affects the occurrence of acute and chronic graft-versus-host disease after a reduced-intensity conditioning regimen by modulating mixed chimerism induction and immune reconstitution

Background. There have been no detailed analyses of the induction of donor cell–type chimerism, the onset and incidence of acute and chronic graft-versus-host disease (GVHD), and the immune recovery kinetics after reduced-intensity stem cell transplantation (RIST). Methods. To address these, with particular emphasis on the impact of the use of antithymocyte globulin (ATG) in RIST, we compared 39 consecutively registered patients who underwent RIST from an HLA-matched related donor and 33 patients who underwent conventional marrow-ablative transplantation. Results. The incidences of grades II to IV acute and chronic GVHD tended to be less in RIST with ATG than in either RIST without ATG or conventional marrow-ablative transplantation. In a multivariate analysis, the predictive factors for acute and chronic GVHD included, respectively, ATG and grades II to IV acute GVHD. In a chimerism analysis, the achievement of complete donor chimera in T-cell lineage was delayed in RIST without ATG compared with RIST with ATG (P =0.038), which might explain the observed delayed onset of acute GVHD in RIST with ATG compared with the other two regimens. The ratio of type 1 and 2 dendritic cells did not affect the development of GVHD, whereas the number of naive CD4+ T cells did. No difference was observed in the incidence of clinically definitive infection, including cytomegalovirus, among the three cohorts, regardless of the use of ATG. Conclusions. We suggest that the conditioning regimen and immunosuppressive strategy after RIST should be carefully balanced against the risk of GVHD and of relapse of the basic disorder caused by the lack of a graft-versus-leukemia benefit.

Successful application of nonmyeloablative transplantation for paroxysmal nocturnal hemoglobinuria.

OBJECTIVE Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematopoietic stem cell disorder that manifests as hemolytic anemia, venous thrombosis, and deficient hematopoiesis. Although allogeneic hematopoietic stem cell transplantation is considered the only curative therapeutic measure, transplant-related mortality is not negligible. Several studies supported the use of nonmyeloablative stem cell transplantation (NST) for patients of advanced age or with organ dysfunction. Hence, we used NST in a PNH patient who suffered from acute renal failure due to repeated episodes of hemolysis. MATERIALS AND METHODS We performed NST using a conditioning regimen consisting of cladribine 0.11 mg/kg x 6, busulfan 4 mg/kg x 2, and rabbit anti-thymocyte globulin 2.5 mg/kg x 2. He received peripheral blood stem cells from his human leukocyte antigen-matched brother. Prophylaxis against graft-vs-host disease was performed with cyclosporine A alone. Chimerism of peripheral blood mononuclear cells was evaluated serially using short tandem repeat analysis and flow cytometry. RESULTS No meaningful regimen-related toxicities were documented. Donor chimerism of 90 to 100% was achieved on day 14 and thereafter. The patient is doing well, without any recurrence of hemolysis 6 months after transplant. Follow-up chimerism studies confirmed stable and functioning donor-type hematopoiesis. CONCLUSIONS NST may become a safe and curative approach in patients with PNH. Further studies are needed to establish the role of NST for treatment of PNH.

A multidisciplinary treatment strategy that includes high-dose chemotherapy for metastatic retinoblastoma without CNS involvement

Summary:The prognosis of patients with metastatic retinoblastoma is poor with conventional chemotherapy and radiation. Since retinoblastoma is highly chemosensitive, dose-escalation of chemotherapeutic agents with stem cell support should be promising. We report our experience with high-dose chemotherapy (HDC) and autologous stem cell transplantation (SCT) in patients with metastatic retinoblastoma. Five patients with metastatic retinoblastoma underwent HDC with autologous SCT following conventional chemotherapy and local radiation therapy. Stem cells (bone marrow in four and peripheral blood stem cells in one) were collected after marrow involvement was cleared. Melphalan was a key drug in all patients, and was administered in combination with other agents such as cisplatin, cyclophosphamide, carboplatin or thiotepa. Three patients are currently alive disease-free at 113, 107 and 38 months, respectively, from the time of SCT. They had no central nervous system (CNS) involvement. The two patients who died of disease had CNS involvement. No long-term sequelae of HDC have been noted. Our treatment strategy using HDC appears to be effective for treating metastatic retinoblastoma without CNS involvement.

A prospective trial to evaluate the safety and efficacy of pravastatin for the treatment of refractory chronic graft-versus-host disease.

This prospective study evaluates the safety and efficacy of pravastatin for the treatment of chronic graft-versus-host disease (GVHD). We included 18 patients with refractory chronic GVHD. Oral pravastatin was started at 10 mg/day, and the dose was increased up to 40 mg/day in 4 weeks. This maximum dose was administered over 8 weeks. There were no severe adverse events caused by pravastatin. A clinical response was observed in the skin score in two patients, mouth score in five patients, eye score in two patients, liver score in three patients, platelet count score in one patient, and weight loss in two patients. The overall response rate was 28%. Immunophenotypic analyses showed that T-helper (Th)1 cells were dominant in all but one patient before treatment and that the Th1/Th2 ratio tended to be lower in the responders than in the nonresponders. A randomized controlled trial is warranted to evaluate the efficacy of pravastatin against chronic GVHD.

A study of rasburicase for the management of hyperuricemia in pediatric patients with newly diagnosed hematologic malignancies at high risk for tumor lysis syndrome

Tumor lysis syndrome (TLS), including hyperuricemia, is a frequent serious complication in patients with hematologic malignancies. This study in Japanese patients evaluated the efficacy, safety, and pharmacokinetic profile of rasburicase in pediatric patients with hematologic malignancies. Patients aged <18 years at high risk for TLS, with newly diagnosed hematologic malignancies, were randomized to intravenous rasburicase 0.15 mg/kg/day (n = 15) or 0.20 mg/kg/day (n = 15) for 5 days. Chemotherapy was started 4–24 h after the first rasburicase dose. Response was defined as a reduction in plasma uric acid to ≤6.5 mg/dL (patients <13 years) or ≤7.5 mg/dL (patients ≥13 years) by 48 h after the first administration, lasting until 24 h after the final administration. Response rates were 93.3 and 100% with rasburicase 0.15 and 0.20 mg/kg/day, respectively. Uric acid levels declined rapidly within 4 h of starting rasburicase administration in both groups. Most adverse events were related to the underlying chemotherapy regimens. Two hypersensitivity reactions, including grade 1/2 pruritus, were considered to be related to rasburicase. Rasburicase is effective and well tolerated for the management of hyperuricemia in Japanese pediatric patients at high risk of developing TLS.

Accuracy of 18F fluorodeoxyglucose positron emission tomography/computed tomography in staging of pediatric sarcomas.

The present study was conducted to clarify the diagnostic accuracy of 18F-fluoro-2-deoxy-D-glucose (18FDG) positron emission tomography (PET)/computed tomography (CT) in the staging in pediatric sarcomas. Fifty pediatric patients with histologically proven sarcomas who underwent 18FDG PET/CT before treatment were evaluated retrospectively for the detection of nodal and distant metastases. Diagnostic accuracy of 18FDG PET/CT in detecting nodal and distant metastases was compared with that of 18FDG PET and conventional imaging (CI). The images were reviewed and a diagnostic consensus was reached by 3 observers. REFERENCE standard was histologic examination in 15 patients and confirmation of an obvious progression in size of the lesions on follow-up examinations. Nodal metastasis was correctly assessed in 48 patients (96%) with PET/CT, in contrast to 43 patients (86%) with PET, and 46 patients (92%) with CI. Diagnostic accuracies of nodal metastasis in 3 modalities were similar. Using PET/CT, distant metastasis was correctly assigned in 43 patients (86%), whereas interpretation based on PET alone or CI revealed distant metastasis in 33 patients (66%) and 35 patients (70%), respectively. Diagnostic accuracy of distant metastasis with PET/CT was significantly higher than that of PET (P=0.002) or CI (P=0.008). False negative results regarding distant metastasis by PET/CT in 7 patients (14%) were caused by subcentimetric lesions (n=4), bone marrow lesion (n=2), and soft tissue lesions (n=1). PET/CT is more accurate and probably more cost-effective than PET alone or CI regarding distant metastasis in pediatric sarcomas.

Cryopreservation of mobilized blood stem cells at a higher cell concentration without the use of a programmed freezer

Cryopreservation of peripheral blood stem cells (PBSC) mobilized by chemotherapy combined with or without granulocyte colony-stimulating factor (G-CSF) is an essential part of procedure for anti-cancer strategies. We evaluated whether a higher cell concentration (2×108/ml) without the use of a programmed freezer was acceptable for the storage of mobilized PBSC in an autologous setting. Mobilized PBSC were enriched to mononuclear cells (MNC) by Percoll separation and then frozen at cell concentrations of 2–5×107/ml (group I, n=20) or 2×108/ml (group II, n=44) without the use of a programmed freezer using 5% DMSO, 6% hydroxy ethyl starch, and 4% autologous serum or human albumin. CD34+ cells purified by ISOLEX300 were frozen at 2×107/ml (group III, n=22) using the same method. The median recovery rates of CD34+ cells and CFU-GM were, respectively, n.d. (not determined) and 88% in group I, 103 and 64% in group II, and 98 and 53% in group III. There was a statistical significance between the recovery rate of CFU-GM in group III and that in group I (p=0.02). The median percentage of cell viability after thawing in each group was 89, 87, and 75%, respectively. The median numbers of days after PBSCT to achieve a WBC of >1.0×109/l, an absolute neutrophil count of >0.5×109/l, and a platelet count of >50×109/l were, respectively, 11, 11 and 15 in group I; 12, 12 and 16 in group II; and 12, 12 and 27 in group III. These results suggest that enriched MNC from mobilized PBSC could be frozen at a higher cell concentration (2×108/ml) without the use of a programmed freezer, leading to reduction of the toxicities associated with infusion of thawed cells and of costly space required for cell storage.