Allogeneic peripheral blood stem cell transplantation (Allo-PBSCT) has been performed as an alternative to bone marrow transplantation (BMT). Here we report poor mobilization with granulocyte-colony stimulating factor (G-CSF) and engraftment kinetics in Allo-PBSCT. Sixteen patients (aged 6-61 yr, median 34 yr) received allogeneic peripheral blood stem cells from related donors (aged 15-68 yr, median 37 yr) after myeloablative therapy. Nine of the patients had standard-risk disease and 7 had high-risk disease. The donors received G-CSF at a dose of 10 micrograms/kg/day by subcutaneous injection for 4 to 6 days. Peripheral blood stem cells were subsequently collected in 1 to 3 aphereses and infused immediately. All patients received G-CSF after transplantation. Fifteen patients underwent Allo-PBSCT and one underwent Allo-PBSCT plus BMT. The mean number of CD34+ cells infused in the 15 Allo-PBSCT patients was 6.32 x 10(6)/kg (range 1.28-14.20). The outcomes were compared with 9 identically treated patients who underwent Allo-BMT. The median times until engraftment for neutrophils > 500/microliter and platelets > 20,000/microliter were 14 (range 10-17) and 15 (range 11-50) days in the Allo-PBSCT group and 17 (range 13-29) and 20 (range 16-160) days in the Allo-BMT group, respectively (p = 0.0177 and p = 0.003). Three donors were considered to have poor mobilization (< 2 x 10(6) CD34+ cells/kg of the recipient); two of them yielded 1.28 and 1.78 x 10(6) CD34+ cells/kg in 3 apheresis procedures. The patients who received cells from these donors showed prompt neutrophil engraftment, but one showed delayed platelet engraftment and another died of grade IV acute GVHD before reaching 20,000 platelets/microliter. An additional bone marrow harvest was necessary from one donor because of poor mobilization(0.17 x 10(6) CD34+ cells/kg). Thus, Allo-PBSCT results in more rapid engraftment. It will be necessary to clarify the minimum CD34+ cell dose for complete engraftment in a larger series of trials.

Chemotherapy plus granulocyte colony-stimulating factor (G-CSF) induced mobilization of peripheral blood stem cells (PBSC) was performed in patients with limited stage small-cell lung cancer. Chemotherapy consisted of cisplatin/etoposide or cisplatin/adriamycin/etoposide. The amounts of CD34 positive cells and granulocyte-macrophage colony forming units (CFU-GM) collected during 2-3 courses of apheresis were 3.1 +/- 2.9 x 10(6)/kg (n = 10) and 3.1 +/- 1.5 x 10(5)/kg (n = 8), respectively. Adequate amounts of PBSC were also harvested even in patients treated with concurrent chemoradiotherapy. Eight patients were successfully treated with high-dose chemotherapy consisting of ifosfamide, carboplatin and etoposide with PBSC transfusion. The patients'-bone marrow reconstruction was rapid and no treatment-related death was observed.

Myeloablation and immunosuppression were considered to be the two major roles of the conditioning regimens for allogeneic stem cell transplantation to facilitate engraftment. It has turned out, however, that immunosuppression is more important and myeloablation is not necessary for engraftment. At the same time, it is considered that the major anti-tumor effect of allogeneic stem cell transplantation depends on the graft-versus-leukemia effect, not on the conditioning regimen itself. In patients with CML who relapsed after allogeneic transplantation, for example, infusion of donor lymphocytes can induce a second complete remission. Non-myeloablative stem cell transplantation (NST) was developed in the late 90s based on these theories. Low-dose, less toxic, so-called "non-myeloablative" preparative regimens have been designed not to eradicate the malignancies, but to provide sufficient immunosuppression to allow donor cells to engraft, while the graft-versus-malignancy effects eradicate the tumor. This strategy permits allogeneic transplantation to be used in patients who are not eligible for conventional, often myeloablative, transplantation because of advanced age or organ dysfunction. Non-myeloablative preparative regimens contain purine analogs, such as fludarabine or cladribine. The NST regimen being used at the National Cancer Center Hospital, Tokyo, Japan, consists of cladribine (0.11 mg/kg x 6 days), busulfan (4 mg/kg x 2 days) and rabbit anti-thymocyte globulin (2.5 mg/kg x 4 days). We enrolled 6 patients in this NST protocol so far: 1 with severe aplastic anemia (sibling-PBSCT), 2 with MDS-RA (1 for sibling-PBSCT and 1 for matched uBMT), 1 with AML-CR2 (matched uBMT), 1 with AML-CR3 (sibling-PBSCT), and 1 with relapsed AML (mismatched related PBSCT). All patients achieved engraftment within 14 days with complete donor chimerism. In addition to leukemias, a graft-versus-malignancy effect was also reported in allogeneic NST of solid tumors, such as renal cell carcinoma and malignant melanoma. The long-term efficacy of NST remains to be determined, and further clinical trials are warranted.

Neural stem cells (NSCs) are multipotential progenitor cells that have self-renewal activities. A single NSC is capable of generating various kinds of cells within the CNS, including neurons, astrocytes, and oligodendrocytes. Because of these characteristics, there is an increasing interest in NSCs and neural progenitor cells from the aspects of both basic developmental biology and therapeutic applications for damaged brain. By understanding the nature of NSCs present in the CNS, extracellular factors and signal transduction cascades involved in the differentiation and maintenance of NSCs, population dynamics and localization of NSCs in embryonic and adult brains, prospective identification and isolation of NSCs, and induction of NSCs into particular neuronal phenotypes, it would be possible to develop a feasible strategy to manipulate cells in situ to treat damaged brain.

Bone marrow abnormalities have been found to play a role in the pathogenesis of rheumatoid arthritis (RA). Recent studies have also confirmed the presence of undifferentiated hematopoietic progenitor cells as well as the expression of stem cell factor in the synovial membranes in RA. The present study investigates whether RA synovial fluids contain factors that can induce differentiation of CD 14 positive/HLA-DR positive cells from undifferentiated hematopoietic cells. Synovial fluid specimens from 18 patients with RA and from 10 control patients, including patients with osteoarthritis and Behcet's disease, were studied. Human promyelocytic leukemia cell line HL 60 (5 x 10(4)/well) were cultured in the presence or absence of the synovial fluids for 5 days, after which the expression of CD 14 and HLA-DR was examined by flow cytometry. The induction of differentiation of CD 14 positive/HLA-DR positive cells or HLA-DR positive cells from HL 60 cells was significantly enhanced more in the presence of synovial fluids from RA patients than in the presence of those of control patients. However, the sera from the RA patients could not induce the differentiation of CD 14 positive/HLA-DR positive cells or HLA-DR positive cells from HL 60 cells. Most cytokines found in RA synovial fluid could not induce the differentiation of HL 60 cells. Of note, treatment of synovial fluids with hyaluronidase significantly decreased or abrogated their capacity to induce the differentiation of HLA-DR positive cells from HL 60. There was no significant difference in the concentration of hyaluronic acid in the synovial fluid between the RA patients and the control patients. These results indicate that there are factors that can induce differentiation of HLA-DR positive cells from undifferentiated hematopoietic cells in the synovial fluid of RA. The data also suggest that such differentiation factors might be related with qualitative abnormality of hyaluronic acid.

A 39-year-old man was admitted with massive ascites. Specimens of ascitic fluid contained numerous cells with a FAB-L3 appearance, and small noncleaved cell lymphoma morphology. These cells expressed CD10, CD19, CD20, CD38, CD45, HLA-DR, and IgM antigens, and were positive for IgM and c-myc protein in cytoplasmic immunostaining tests. Clonal rearrangements of IgH and c-myc genes were detected by Southern blot analysis. No mass lesions were found by physical examination, and systemic computed photography did not reveal enlargement of lymph nodes, spleen, or liver. Bone marrow aspiration showed no infiltration of malignant cells. Ga scintigraphy indicated hot lesions only in the abdomen. These findings suggested that Burkitt's lymphoma had developed in the peritoneal cavity as a primary lymphomatous effusion. Chemotherapy with methotrexate, cyclophosphamide, vincristine, doxorubicin, etoposide, and dexamethasone was effective, and the patient has been free from the disease for 1 year since completion of consolidation treatment with autologous peripheral blood stem cell transplantation.

Gene therapy is a promising strategy for cancer treatment. The strategy is categorized to some fields based on the anti-cancer mechanism. p53 gene therapy and antisense therapy exert the cytotoxic effect on cancer cells by apoptosis induction. In suicide gene therapy, expressed suicide gene product kills the cancer cells in combination with prodrug which metabolite is cytotoxic agent. Oncolytic virus replicates in the tumor selectively and destroys the cancer cells. Immunogene therapy potentiates the antigenicity of cancer cells or activate the immune effector cells. In antiangiogenesis gene therapy, neovascularization is inhibited with antiangiogenic molecule gene such as angiostatin. On the other hand, bone marrow stem cells are protected from high dose anti-cancer agents by the transfer of multi-drug resistant gene.

Autoimmune diseases such as systemic lupus erythematosus (SLE) are known to be causative disorders of reactive hemophagocytic syndrome (HPS). We recently encountered a case of HPS associated with the presence of antiphospholipid antibodies (aPL). This patient showed severe thrombocytopenia (0.2 x 10(4)/microliter) and moderate anemia (Hb; 7.6 g/dl). Bone marrow smears showed normal cellularity and an increase in mature-looking histiocytes scattered among the hematopoietic cells, which accounted for approximately 3% of all nucleated cells and were distributed unevenly. These cells showed marked phagocytosis of hematopoietic cells, including megakaryocytes, erythroblasts, and a few neutrophils. In this patient, there is no possible causative factor of HPS (such as viral infection, lymphoma, and systemic lupus erythematosus) except the presence of aPL. There have been no previously reported cases describing the relationship between aPL and HPS. This case indicate that attention should be given to the possibility that certain patients with aPL-associated cytopenia may display accompanying intramedullary hemophagocytic phenomena.

The efficacy and safety of high-dose lenograstim on CD34 positive (CD34+) cell mobilization into peripheral blood were investigated in 18 healthy male volunteers. The volunteers were divided into 3 lenograstim dose groups of 6 subjects each. Lenograstim was administered at a dose of 2, 5, or 10 micrograms/kg/day, b.i.d. by subcutaneous injection for a total of 5 days. The median peak number of CD34+ cells/microliter of blood was 16.3, 53.9, and 96.6 in the 2, 5, and 10 micrograms/kg/day groups, respectively. A positive correlation was observed between the peak CD34+ level and dose of lenograstim (P = 0.002). The percentage of volunteers achieving more than 50 CD34+ cells/microliter of blood was significantly higher in the 10 micrograms/kg/day group (83.3%, P = 0.010) than in the 2 micrograms/kg/day group (0%). On the subject of safety, at least 1 adverse drug reaction (ADR) was observed in each of the volunteers, and a total of 12, 33, and 45 ADRs were observed in the 2, 5, and 10 micrograms/kg/day groups, respectively. A dose-dependent increase in the number of ADRs was also observed, including an elevation of LDH (P < 0.001), bone pain (P < 0.001), and fatigue (P = 0.008). However, no volunteers required symptomatic treatment or discontinuation of lenograstim. We concluded that administration of lenograstim at a dose of 10 micrograms/kg/day for 5 days is highly effective for CD34+ cell mobilization into peripheral blood and tolerable in healthy volunteers.

The present therapy for malignant lymphoma including stem cell transplantation, has been greatly developed. However, treatments still remain ineffective for many patients. Gene therapy is providing new strategies for the treatments of malignant lymphoma. There are three major approaches; 1) killing the tumor cell itself by introducing anti-sense genes against oncogene, tumor suppressor genes or drug-sensitive genes. 2) modifying the immune response by introducing genes that will trigger anti-tumor response or tumor specific genes to antigen presenting cell. 3) decreasing the sensitivity of hemopoietic cells by introducing drug resistance genes. We describe here the current and future applications of gene therapy for malignant lymphoma.

The objective of our study was to obtain a predictor of the timing for peripheral blood stem cell (PBSC) collection using routine blood cell counts. For that purpose, we compared recovery kinetics of peripheral blood cells and CD34+ cells in non-Hodgkin's lymphoma patients who were given granulocyte-colony stimulating factor for PBSC collection after CHOP therapy. Peaks in the monocyte/WBC ratio and reticulocyte high fluorescence ratio (HFR) were observed 2 to 3 days prior to the peak CD34+ cell count. In addition, the appearance of immature granulocytes in peripheral blood correlated well with increases in CD34+ PBSC number. These findings suggested the peak monocyte/WBC ratio, HFR, and immature granulocyte count can be used as predictors of the timing for PBSC harvests.

Thiazolidinedione (TZD), a new class of anti-diabetic agents, is known to promote adipocytic differentiation by activating peroxisome proliferator-activated receptor-gamma (PPAR gamma). In the bone marrow, osteoblasts and adipocytes are derived from common mesenchymal stem cells or stromal cells, which also play crucial roles in the generation of osteoclasts from their progenitor hematopoietic cells. Recent in vitro studies demonstrated that TZDs promote adipocytic differention of the stromal cells. However, whether or not this affects osteoblastic differentiation is unclear. On the other hand, TZDs clearly inhibit osteoclast-like cell formation and bone resorption in vitro. These results indicate that TZDs have direct effects on bone cells. However, little is known about their in vivo effects on bone. Our recent study demonstrated that troglitazone, a TZD, decreased bone resorption markers before it affected glycemic indices in type2 diabetics, suggesting TZDs affects bone in vivo and may be beneficial for bone health in type2 diabetics.

Myelosuppression is a major dose-limiting factor in cancer chemotherapy. Introduction of drug-resistance genes into bone marrow cells of cancer patients has been proposed to overcome this limitation. In theory, any gene whose expression protects cells against the toxic effects of chemotherapy should be useful in vivo for this purpose. Among such genes, human multidrug-resistance gene (MDR1) has been studied most extensively for this purpose, and clinical trials of drug-resistance gene therapy have been started in the US for cancer patients who undergo high-dose chemotherapy with autologous hematopoietic stem cell transplantation. In Japan, our clinical protocol of MDR1 gene therapy "A clinical study of drug-resistance gene therapy to improve the efficacy and safety of chemotherapy against breast cancer" has been submitted to the government. To improve the efficacy and safety of this drug-resistance gene therapy, we have constructed a series of MDR1-bicistronic retrovirus vectors using a retrovirus backbone of Harvey murine sarcoma virus and internal ribosome entry site (IRES) from picornavirus to co-express a second gene with the MDR1 gene. MDR1-MGMT bicistronic vectors can be used to protect bone marrow cells of cancer patients from combination chemotherapy with MDR1-related anticancer agents and nitrosoureas. In addition, MDR1-bicistronic retrovirus vectors can be designed to use the MDR1 gene as an in vivo selectable marker to enrich the transduced cells which express therapeutic genes, if disease is curable by the expression of a single-peptide gene in any types of bone marrow cells or peripheral blood cells.

The possibility of gene therapy for inherited diseases with a single gene mutation in Figure 1 had been verified by the successful treatment with bone marrow transplantation. As the gene therapy method and theory has been progressing rapidly, it is expected that gene therapy will overcome the complications of bone marrow transplantation. Of these inherited diseases, chronic granulomatous disease (CGD) is the one of the most expected disease for gene therapy. CGD is an inherited immune deficiency caused by mutations in any of the following four phox genes encoding subunits of the superoxide generating phagocyte NADPH oxidase. It consists of membranous cytochrom b558 composed of gp91 phox and p22 phox, and four cytosolic components, p47 phox, p67 phox, rac p21 and p40 phox, which translocate to the membrane upon activation. In our group study, more than 220 CGD patients has been enrolled. The incidence of CGD patients was estimated as 1 out of 250,000 births. The expected life span of the CGD patients is 25 to 30 years old by the Kaplan Meier analysis. Comparing with the ratio of CGD subtype in US and Europe, that with p47phox deficiency is lower (less than 10%/o vs. 23%) and that of gp91 phox deficiency is higher (more than 75% vs. 60%). Prophylactic administration of ST antibiotics and IFN-gamma and bone marrow transplantation have been successfully employed in our therapeutic strategy. However, it is necessary to develop the gene therapy technology for CGD patients as more promising treatment. In the current study we constructed two retrovirus vectors; MFGS-gp91/293 SPA which contains only the therapeutic gp91 phox gene, a bicistronic retrovirus pHa-MDR-IRES-gp91/PA317 which carries a multi drug resistant gene (MDR1) and the gp91phox gene connected with an internal ribosome entry site (IRES). We demonstrate high efficiency transduction of gp 91 phox to CGD EB virus established cell line with high levels of functional correction of the oxidase by MFGS-gp91 and by pHa-MDR-IRES-gp91, respectively. We also demonstrate sufficient transduction of gp91 phox to CD34+ hematopoietic stem cell from the patients with gp91 phox deficiency by MFGS-gp91/293 SPA. Our current studies suggest that the combination of the 293-SPA packaging system and the bicistronic retrovirus system inserted MDR1 gene make our CGD gene therapy more feasible for clinical application.