Oku N

Effects of lnterleukin-3 and lnterleuki-6 on Peripheral Blood Cells from Multiple Myeloma Patients and Their Clinical Significance

The effects of interleukin-3 (IL-3) and interleukin-6 (IL-6) on nonadherent mononuclear cells (NMC) from the peripheral blood of 28 patients with multiple myeloma (MM), 3 patients with monoclonal gammopathy of undetermined significance (MGUS), and 3 normal controls were investigated. In 15 of 27 evaluable patients with MM, monoclonal-cytoplasmic-immunoglobulin (cIg)-positive plasma cells appeared from the T-cell-depleted NMC after 10 days of culture in the presence of IL-3 and IL-6. These changes were not observed in the T cell fraction of myeloma blood or in the T-cell-depleted NMC obtained from cases of MGUS or from normal controls. The percentage of cIg-positive plasmacytoid cells after 10 days of culture was significantly higher in the presence of both IL-3 and IL-6 than with each interleukin alone or the control medium. Furthermore, these changes were often observed in untreated patients. These findings suggest that myeloma precursor cells exist in the peripheral blood of MM patients, especially at diagnosis, and differentiate into cIg-positive cells in the presence of IL-3 and IL-6. This assay may be useful in discriminating the early stage of myeloma from MGUS.

Detection of minimal residual myeloma cells by dual parameter analysis of DNA and cytoplasmic immunoglobulin.

We demonstrated the utility of dual parameter analysis of DNA and cytoplasmic immunoglobulin for the detection of minimal residual myeloma cells in bone marrow and peripheral blood. This method is sensitive: even 0.1% of contaminating myeloma cells could be detected in peripheral blood of myeloma patients and in the model experiments using cell lines. This method is useful for the selection of patients undergoing high-dose chemotherapy and autologous blood stem cell transplantation.

Mouse anti-human interleukin-6 receptor monoclonal antibody inhibits proliferation of fresh human myeloma cells in vitro.

Interleukin‐6 (IL‐6) is a major growth factor in multiple myeloma. We investigated the effect of mouse anti‐human IL‐6 receptor monoclonal antibody (anti‐IL‐6R mAb) on the in vitro proliferation of freshly isolated myeloma cells from 21 patients to evaluate the therapeutic potential. The addition of anti‐IL‐6R mAb inhibited more than 30% of the spontaneous proliferation of myeloma cells in 9 of 21 cases in a dose‐ (0.1 to 20 /μ/ml) and time‐dependent manner. The inhibitory effects of anti‐IL‐6R mAb did not differ significantly from that of anti‐IL‐6 mAb, and were correlated with the extent of the response of myeloma cells to IL‐6. Flow cytometric analysis showed that all myeloma cells expressed IL‐6R, whose intensity was not correlated with either the extent of response of myeloma cells to IL‐6 or the inhibitory effects of anti‐IL‐6R mAb on proliferation of myeloma cells. Although our study showed heterogeneity in the proliferative responses of myeloma cells to IL‐6 and anti‐IL‐6R mAb, these observations suggest the possibility of using anti‐IL‐6R mAbs for treating some patients with multiple myeloma whose growth depends on IL‐6.

Recombinant Human Granulocyte Colony-Stimulating Factor in Combination with Continuous Infusion of Cytosine Arabinoside for the Treatment of Refractory Acute Myelogenous Leukemia

Because recombinant human granulocyte colony-stimulating factor (G-CSF) has been reported to increase the sensitivity of acute myelogenous leukemia (AML) blast cells to cytosine arabinoside (Ara-C) in vitro, we treated a patient with refractory AML with an Ara-C-based regimen in combination with G-CSF (G-CSF/Ara-C therapy). G-CSF (50 micrograms/m2/day, subcutaneous injection) was administered simultaneously with a continuous intravenous infusion of Ara-C (70 mg/m2/day). Complete remission was achieved, however, severe neutropenia, documented infection, stomatitis, and diarrhea were observed. In vitro studies using 3H-thymidine uptake and dual parameter flow-cytometric analysis of DNA and proliferating cell nuclear antigen showed that leukemic blast cells in S phase were increased after incubation with G-CSF. G-CSF also enhanced expression of the transferrin receptor (CD71) on blast cells in vitro. These observations suggest that G-CSF/Ara-C therapy may be useful in the treatment of high-risk AML.

Novel Type of Clonally Involved Cytoplasmic Immunoglobulin-Negative Cells in Multiple Myeloma: Flow Cytometric Study

In order to identify myeloma cells and their precursor cells, we studied bone marrow samples from 39 patients with multiple myeloma, including 2 with plasma cell leukemia, using dual parameter cytometry of both DNA and cytoplasmic immunoglobulin (Cyt-Ig). Myeloma cells from 25 patients (64.1%) were aneuploid and those from the remaining 14 patients were diploid. In 25 patients with aneuploid myeloma, we found a small component of cells which had aneuploid DNA content without Cyt-Ig in addition to myeloma cells showing aneuploidy with Cyt-Ig. These aneuploid Cyt-Ig-negative cells were considered to be clonally involved because they were aneuploid, and detected predominantly in patients with stage III myeloma. This suggests that these cells may contribute to disease progression. The characteristics of these cells are described and the relationship between these cells and myeloma precursor cells is discussed.

Trilineage Response in Severe Aplastic Anemia Following Long-Term Therapy with Recombinant Human Granulocyte Colony-Stimulating Factor

We investigated the effects of long-term therapy with recombinant human granulocyte colony-stimulating factor (rhG-CSF) in a 69-year-old man with severe aplastic anemia (SAA). The patient was too old to receive a bone marrow transplantation, and high-dose methylprednisolone and antilymphocyte globulin were ineffective. We administered rhG-CSF in combination with metenolone acetate. Trilineage blood cell components were recovered 6 months later. These findings suggest that long-term G-CSF therapy may be beneficial in patients with SAA who are not candidates for bone marrow transplantation.

Chromosome 14 Abnormality with a Breakpoint of p12 in Adult T-cell Leukemia

We describe a patient with adult T-cell leukemia (ATL) with a 14p chromosomal abnormality. Cytogenetic study revealed two clonal populations of leukemic cells in the peripheral blood sample. Both clones were karyotypically related to each other. One of them showed rearrangement of chromosome 14 at break band p 12 (14p12) in addition to + 3, + 7, -X and del(6) (q14q21). The nucleolar organizer region (NOR) is assigned to the band 14p12 and the role of the rearrangement of chromosome 14p12 in the pathogenesis of ATL is discussed.