Anti-lymphoma effect of naproxen and indomethacin in a patient with relapsed diffuse large B-cell lymphoma.

A 77-year-old man with relapsed non-Hodgkin's lymphoma, diffuse large B-cell type, was treated with naproxen, a nonsteroidal anti-inflammatory drug (NSAID), for paraneoplastic fever. A dramatic disappearance of not only the fever but also generalized lymphadenopathy was observed. Naproxen was continued, and he maintained remission for 10 months. When relapse of lymphoma occurred in spite of continuous naproxen administration, indomethacin, another type of NSAID, was tried. Surprisingly, rapid regression of lymphoma occurred again and was maintained for almost 1 year. These results indicate that NSAIDs are effective in some patients with non-Hodgkin's lymphoma.

K-252a-induced polyploidization and differentiation of a human megakaryocytic cell line, Meg-J: transient elevation and subsequent suppression of cyclin B1 and cdc2 expression in the process of polyploidization.

Megakaryocytes are unique haemopoietic cells which undergo DNA replication, giving rise to polyploid cells. However, little is known about the mechanism of megakaryocytic polyploidization. To address this issue, we used the human megakaryocytic cell line Meg-J. In the presence of K-252a (an indolocarbasole derivative), Meg-J cells stopped proliferation and exhibited additional megakaryocytic features, including morphological changes, polyploidization, and increases in the levels of surface expression of platelet glycoprotein (GP) IIb/IIa and GPIb. Thrombopoietin (TPO) promoted the K-2 52a-induced polyploidization and megakaryocytic differentiation. In the process of K-252a-induced polyploidization, levels of expression of both cdc2 and cyclin B1 were elevated transiently and subsequently decreased. This suggested that the polyploidization process in Meg-J cells was at least in part associated with a transient elevation and subsequent decrease in the expression of cdc2/cyclin B1 complex, a critical kinase involved in G2/M cell cycle transition.

Control of retinoblastoma protein-independent hematopoietic cell cycle by the pRB-related p130.

The retinoblastoma tumor suppressor protein (pRB) is a potent inhibitor of mammalian cell growth and the functional inactivation of pRB is widely presumed to be essential for progression of the cell cycle from G1 phase. In this work, the generality of pRB-based cell cycle control in mammalian cells was addressed by conditionally expressing pRB in cytokine-dependent hematopoietic cells. We show herein that these cells are able to progress through the cell cycle in response to cytokine despite the continued presence of supraphysiological amounts of wild-type pRB or phosphorylation-resistant pRB mutants. However, their growth was strongly blocked by ectopic expression of the pRB-related pocket protein, p130. This growth inhibition required the E2F-binding pocket domain but not the cyclin-binding domain of p130. Furthermore, increased amounts of the p130-controlled E2F, termed E2F-4, potentiated the mitogenic response of the cells to cytokine and the constitutive overexpression of E2F-4 rendered the cells cytokine-independent. Our results indicate the existence of a non-pRB-based cell cycle whose operation depends primarily on the interplay between p130 and E2F-4 in certain hematopoietic cells.

Transcription factor NF-E2 is essential for the polyploidization of a human megakaryoblastic cell line, Meg-J.

Transcription factors regulating the process of megakaryocyte development remain largely unclarified. To clarify them further, we used a human megakaryoblastic cell line, Meg-J, which showed prominant polyploidization and augmented platelet glycoprotein (GP) Ib expression after incubation with thrombopoietin (TPO, c-mpl ligand) and K252a (an indolocarbasole derivative). Under these conditions, we analyzed the expression of the transcription factors and observed that the expression of NF-E2 p45, but not those of GATA-1, GATA-2, Tal-1/SCL, Evi-1, and MafK, was increased after TPO and K252a stimulation. Gel-shift assay confirmed the enhanced binding activity to the NF-E2 site. The abolishment of NF-E2 p45 with NF-E2 antisense oligomers inhibited TPO plus K252a-induced polyploidization. These findings suggest that NF-E2 p45 is essential for the polyploidization of megakaryocytic cells.

Effect of thrombopoietin (c-Mpl ligand) alone and in combination with other hematopoietic growth factors on human megakaryocytopoiesis in serum-free cultures.

The effect of human recombinant (hr) thrombopoietin (TPO) on human megakaryocytopoiesis was studied in a serum-free system. hrTPO induced megakaryocyte colony formation by purified CD 34-positive cells and polyploidization of megakaryocytes by purified CD41a-positive cells. hrTPO gave rise to much smaller colonies which appeared at an earlier time compared to the use of human recombinant interleukin-3 (hrIL-3), suggesting that hrTPO predominantly affects the population of megakaryocyte progenitor cells in the late stage. hrIL-3 additively increased the hrTPO-induced megakaryocyte colony formation by CD34-positive cells. The hrTPO-induced megkaryocyte colony formation was also increased by the presence of hrIL-6, hrIL-11, human recombinant erythropoietin (hrEpo) or human recombinant stem cell factor (hrSCF), none of which stimulated megakaryocyte colony growth when added alone. The combined addition of hrTPO, hrIL-3 and hrSCF to CD34-positive cells markedly stimulated megakaryocyte colony formation and produced large numbers of megakaryocytes. hrTPO stimulated the polyploidization of CD34-positive cell-derived megakaryocytes in liquid culture. However, the addition of hrIL-6, hrIL-11 or hrEpo to hrTPO did not further enhance the hrTPO-induced polyploidization. These findings indicate that at the megakaryocyte progenitor cell level, the effect of hrTPO can be promoted by the presence of various hematopoietic growth factors involved in human megakaryocytopoiesis.

Mechanism of action of antithymocyte globulin in the treatment of aplastic anaemia: in vitro evidence for the presence of immunosuppressive mechanism.

Antithymocyte globulin (ATG) is one of the effective drugs used in the treatment of aplastic anaemia (AA). Although it has been speculated that the mechanism of action of ATG is mediated by its immunosuppressive effect on lymphocytes which might have an inhibitory effect on haemopoietic stem and progenitor cells, no definite evidence of the presence of such a mechanism has been demonstrated. In this study we investigated whether such a mechanism is truly operating in ATG therapy for AA. In five patients who responded to ATG, bone marrow cells were obtained after haematological recovery and CD34-positive cells were separated by immunobeads. Autologous CD34-positive cells were mixed with autologous peripheral CD4- or CD8-positive cells obtained before ATG therapy and after haematological recovery, liquid-cultured for 12h, and then cultured in methylcellulose for 14d in the presence of haemopoietic growth factors. In all five cases studied, only the CD8 cells obtained before ATG therapy suppressed the colony forming unit-granulocyte-macrophage (CFU-GM)- and burst forming unit-erythroid (BFU-E)-derived colony formation. This result is definite evidence that one of the mechanisms of action of ATG in AA is an inhibitory effect on CD8-positive cells which have suppressive activity for the growth of haemopoietic progenitor cells.

Effect of interleukin 11 on normal and pathological thrombopoiesis.

Interleukin 11 (IL-11) is a stromal cell-derived cytokine that has multiple effects on hematopoietic and nonhematopoietic systems. In vitro, it enhances the growth of early progenitors and promotes megakaryocytopoiesis and erythropoiesis. In healthy animals, IL-11 administration stimulates megakaryocyte maturation and increases peripheral platelet counts. IL-11 accelerates the recovery of peripheral neutrophil, erythrocyte, and platelet counts in mice that have undergone cytoablative treatment. Therefore, IL-11 may be useful clinically as an agent promoting recovery from hematopoiesis. However, its clinical use in patients with hematological malignancies may be restricted because IL-11 has been reported to stimulate some leukemia and myeloma cells. In the United States, phase I trials have shown that IL-11 accelerates recovery from chemotherapy-induced or bone-marrow transplantation (BMT)-induced thrombocytopenia. In Japan, phase II trials studying the thrombopoietic effect of IL-11 in patients with solid tumors postchemotherapy, in patients undergoing BMT, and in patients with aplastic or refractory anemia are now under way. Recently, thrombopoietin (TPO) has been cloned, and its thrombopoietic effect and accelerating effect on platelet count recovery in thrombopoietic states have been demonstrated in animal models. The physiological effect of TPO is restricted to hematopoiesis; therefore, it may have fewer side effects than IL-11. However, in addition to its hematopoietic effect, IL-11 administration to mice that have undergone cytoablative therapy significantly decreases morbidity and mortality due to chemotherapy-related endogenous infections caused by gut microorganisms. Therefore, IL-11 can be used in patients postchemotherapy and post-BMT not only to promote platelet recovery but also to prevent life-threatening infections. The use of in-vitro-expanded hematopoietic stem cells for BMT or as target cells for gene therapy is one of the most exciting areas in the field of medicine. Since IL-11 can expand hematopoietic progenitor-cell populations when used in combination with other cytokines, it may be useful as an ex vivo hematopoietic progenitor-cell-amplifying agent.

Hypereosinophilic syndrome in Hodgkin's disease with increased granulocyte-macrophage colony-stimulating factor.

We report a patient with eosinophilia accompanied by Hodgkin's disease who showed remarkable increase in granulocyte-macrophage colony-stimulating factor (GM-CSF) in plasma but no increase in interleukin-5 (IL-5). The plasma GM-CSF level normalized as eosinophilia and lymphadenopathy disappeared after chemotherapy. Immunohistochemical study with immunoperoxidase staining technique showed a positive stain in lymph node cells by monoclonal anti-GM-CSF antibody. Eosinophilia is often accompanied by Hodgkin's disease, and several cases have been reported to show high levels of plasma IL-5. To our knowledge, this is the first report to show a high level of plasma GM-CSF in Hodgkin's disease with eosinophilia.

Rapidly progressive pulmonary alveolar proteinosis in a patient with chronic myelogenous leukemia.

A 46-year-old man with chronic myelogenous leukemia (CML) was admitted to our hospital because of high fever. The chest radiographs showed bilateral groundglass-like infiltrates in the perihilar region. Transbronchial lung biopsy (TBLB) and autopsy revealed PAS-positive granular materials characteristic of pulmonary alveolar proteinosis (PAP). He had received interferon-alpha since the time of CML diagnosis. Busulfan had never been administered. Altered cell-mediated immunity was thought to be closely related to the development of PAP.

[Hypoplastic leukemia successfully treated by oral administration with cytarabine ocfosfate].

A 73-year-old man was admitted to our hospital with pancytopenia in December, 1992. The data of his peripheral blood were as follows: WBC 1,100/microliters (stab 9.0, seg 11.5, eosin 3.5, mono 1.0, lymph 75.0), RBC 176 x 10(4)/microliters, Hb 6.6 g/dl, platelet 4.6 x 10(4)/microliters. Bone Marrow was hypocellular (cell count 1.4 x 10(4)/microliters) and consisted of 30% blasts (peroxidase positive). He was diagnosed as having hypoplastic leukemia. Oral administration of cytarabine ocfosfate (50 mg/day) was begun from the 5th of January, 1993. The dose of cytarabine ocfosfate was increased to 100 mg/day since the 13th of January, 1993, and he was discharged from the hospital on the 23rd of January, 1993. Since then, he has been treated with cytarabine ocfosfate alone in the outpatient clinic. Pancytopenia began to improve in one month, and the data on the 7th of May, 1993 were as follows: WBC 3,500/microliters (stab 2.0, seg 37.5, eosin 1.5, baso 1.0, mono 16.5, lymph 41.5), RBC 249 x 10(4)/microliters, Hb 10.4 g/dl, platelet 15.4 x 10(4)/microliters. Bone marrow became normocellular (cell count 22.0 x 10(4)/microliters) and blasts decreased to 3.0%, and complete remission was confirmed. There were no adverse effects.