Interleukin-4 induces proliferation of adult T-cell leukemia cells

Abstract: To evaluate the effect of IL-4 on the growth of leukemic cells from adult T-cell leukemia (ATL) patients (ATL cells) and determine whether the IL-4 autocrine mechanism is involved in the growth of ATL cells, we studied the proliferative response of ATL cells, from 11 patients, cultured in the presence or absence of IL-4 in vitro. Leukemic cells from 10 of the 11 patients examined proliferated in response to both IL-2 and IL-4 in a dose-dependent manner. The proliferative response to IL-4 was higher than that obtained with IL-2 in 8 patients. The expression of the IL-2 receptor (IL-2R) αα-chain in leukemic cells from some patients was also enhanced by IL-4. The IL-4 receptor was demonstrated by flow cytometry on the surface of ATL cells. Neither IL-4-induced proliferation of ATL cells nor IL-4-induced IL-2R expression on ATL cells was inhibited by anti-Tac or anti-IL-2 antibody and, therefore, these effects of IL-4 are considered independent of endogenous IL-2 activity. However, IL-2 and IL-4 were undetectable in the culture supernatants of ATL cells from any patient by enzyme-linked immunosorbent assay. Interferon-γ (IFN-γ) partially inhibited IL-2- or IL-4-induced proliferation of ATL cells. These results suggest that leukemic cells from ATL patients proliferate by an IL-2 or IL-4 paracrine mechanism in lymphoid tissue in vivo and that IFN-γ inhibits IL-2- or IL-4-induced proliferation of ATL cells.     

Characterization and regulation of interleukin-4 receptor in adult T-cell leukemia cells

We studied the expression of the receptor of interleukin (IL)-4, one of the T cell growth factors, on fresh peripheral blood leukemic cells from adult T-cell leukemia (ATL) patients. Flow cytofluorometric analysis with a monoclonal antibody to the IL-4 receptor (IL-4R) were used to investigate whether expression of IL-4R on ATL cells is different from that on normal lymphocytes and other types of leukemic cells. Leukemic cells from acute type ATL patients synthesize IL-4R without stimulation, at levels much higher than normal resting lymphocytes and other types of leukemic cells. Furthermore, leukemic cells from acute type ATL showed higher IL-4R expression than that of chronic type ATL or human T-cell leukemia virus type I carriers. In addition, there was correlation between expression of IL-4R on the cell surface and the proliferative response to IL-4. Both IL-4 and IL-2 induced upregulation of IL-4R on activated normal T cells but not on ATL cells. These results suggest that abnormal expression of IL-4R may display different biological activities in ATL compared with other types of leukemia. Furthermore, the high expression of IL-4R in ATL may be involved in the proliferation of leukemic cells and the leukemogenesis in this disease.     

Interleukin-2 production by primary adult T cell leukemia tumor cells is macrophage dependent.

We have investigated the cellular requirements for IL-2 production by autocrine proliferating tumor cells from four patients with adult T cell leukemia (ATL). Cultures of these ATL cells both produced endogenous IL-2 protein in the absence of added mitogen and proliferated at higher levels when exogenous recombinant IL-2 was added. Depletion of macrophages in the tumor cell cultures resulted in a sharp decline in tumor cell IL-2 production, while re-addition of macrophages reconstituted this response. Macrophage-derived factors including IL-6 and IL-1 also reconstituted IL-2 production in these macrophage depleted cultures. These results raise the possibility that macrophages may play a central role in HTLV-I mediated immortalization of T cells.     

Recombinant human interleukin-4 inhibits the production of granulocyte-macrophage colony stimulating factor by blood mononuclear cells

Summary. The effect of recombinant human (rh) interleukin-4 (rIL-4) on human blood BFU-E was investigated using two populations of cells: platelet-depleted low-density mononuclear cells (FH, Pl⁻ cells), as unpurified cells, and highly purified BFU-E. When FH, Pl⁻ cells were cultured with rherythropoietin (rEp), rIL-4 inhibited BFU-E growth in a dose-dependent manner. However, the addition of rIL-4 did not affect rh-interleukin-3 (rIL-3) supported BFU-E growth. Limiting dilution analysis (LDA) of FH, Pl⁻ cells showed that rIL-4 suppressed endogenous production of burst-promoting activity (BPA) by accessory cells. Highly purified BFU-E were used as target cells to measure BPA in the conditioned medium (CM) that was prepared by FH, Pl⁻ cells. When 100 purified BFU-E were cultured in 0·5 ml clots with 20% (vol/vol) of the CM, the number of BFU-E colonies was increased by the CM. The increase was significantly reduced by the addition of the CM prepared in the presence of rIL-4, but anti-IL-4 blocked the effect of rIL-4. The concentration of IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in CM was determined by an enzyme-linked immunoadsorbent assay (ELISA). The spontaneous production of GM-CSF but not IL-3 was detected, and this was significantly decreased in the presence of rIL-4. Anti-GM-CSF but not anti-IL-3 inhibited CM supported BFU-E growth, indicating that the main BPA in the CM is GM-CSF and that rIL-4 suppresses the spontaneous production of GM-CSF by accessory cells. From these studies, we conclude that rIL-4 has a unique mechanism as a negative regulator on erythropoiesis through the inhibition of BPA production by blood mononuclear accessory cells.     

Interleukin-4 inhibits interleukin-11 production by rheumatoid synovial cells

OBJECTIVE: To examine the effect of interleukin-4 (IL-4) on IL-11 production by rheumatoid synovial cells. METHODS: Freshly isolated rheumatoid synovial cells (FRS) were obtained by collagenase digestion of rheumatoid arthritis (RA) synovial tissue specimens taken at the time of operation. Rheumatoid synovial cells at four to eight passages were used as cultured rheumatoid synovial fibroblasts (RSF). IL-11 concentration was measured by ELISA. RESULTS: IL-4 inhibited the production of IL-11 by FRS in a dose-dependent manner. This inhibition was observed in FRS obtained from six patients, and the mean inhibition was 46.5%. The inhibitory effect of IL-4 on IL-11 production was cancelled by the addition of anti-IL-4 antibody. IL-4 also inhibited IL-11 production by IL-1alpha-stimulated cultured RSF. CONCLUSION: IL-4 inhibited IL-11 production by rheumatoid synovial cells. IL-4 has a protective effect on bone resorption. On the contrary, IL-11 participates in bone resorption via osteoclastogenesis. Therefore, IL-4 may exert its protective effect on bone resorption, at least in part, via inhibition of IL-11 production in rheumatoid joints.     

Granulocyte colony-stimulating factor production by adult T-cell leukaemia cells

We previously demonstrated that, in about 30% of primary adult T-cell leukaemia (ATL) cases, the leukaemic cells proliferated in response to granulocyte colony-stimulating factor (G-CSF). In the present report, we describe five patients with the acute leukaemia type of ATL who showed marked neutrophilia and elevated serum G-CSF concentrations in the absence of infection. We further examined two of these patients for detailed clinical features and cellular characteristics of the tumour cells. The white blood cell counts of both patients were 62 x 10(9)/l, consisting of approximately 90% neutrophils and 10% ATL cells. Serum concentrations of G-CSF in the two patients were 138 pg/ml and 93 pg/ml. The G-CSF concentrations in supernatants of short-term cultures of the patients' peripheral blood T-cells were 2 5 pg/ml and 13 pg/ml respectively. Immunostaining with anti-G-CSF antibody demonstrated G-CSF production by primary ATL cells in both cases. The neutrophil count fluctuated simultaneously with activity of ATL. Primary ATL cells from one patient were shown to proliferate in response to G-CSF in vitro. These results suggest autocrine growth stimulation of primary ATL cells in a subgroup of patients.     

CD8-positive adult T-cell leukemia cells with an integrated defective HTLV-I genome show a paracrine growth to IL-2

We describe a 50-year-old man with adult T-cell leukemia complicated by laryngeal tuberculosis whose tumor cells proliferate in response to IL-2 in a paracrine manner. On admission, the patient's white blood cell count was 17,900/mm³; 73% were abnormal lymphocytes with convoluted nuclel. FACS analysis showed that the tumor cells were CD4-negative, CD8-positive T cells. Southern blot analysis of tumor cells revealed integration of a defective HTLV-I genome lacking gag and pol genes. He was diagnosed with chronic ATL complicated by laryngeal tuberculosis. The primary leukemic cells expressed IL-2Rα and IL-2Rβ detected by FACS and Northern blot analysis and showed marked growth in response to exogenously added recombinant IL-2 in short-term cultures. Northern blot analysis did not show any IL-2 mRNA. We have previously demonstrated that primary leukemic cells from some ATL patients grow in response to IL-2 in an autocrine or paracrine manner. These results suggest that in CD8 ATL, IL-2 may beinvolved in a paracrine manner. © 1994 Wiley-Liss, Inc.     

Elevated soluble CD4 levels in the cerebrospinal fluid in patients with adult T-cell leukemia

Levels of the soluble form of the leukocyte surface antigen CD4 (sCD4) were measured by enzyme linked immunosorbent assay (ELISA) in the cerebrospinal fluid (CSF) of patients with adult T-cell leukemia (ATL) and other malignant and non-malignant diseases. All patients with ATL and meningeal infiltration had markedly elevated levels of sCD4 in the CSF (53.7 ± 34.9 U/ml). ATL patients without CSF pleocytosis often had elevated levels of sCD4 (15.1 ± 9.2 U/ml). Non-ATL patients with CSF pleocytosis had elevated levels of sCD4 (23.3 ± 12.2 U/ml) and those without CSF pleocytosis also showed elevation of sCD4 levels (16.8 ± 9.3 U/ml). However, the mean levels of sCD4 in CSF from these patients were significantly lower than ATL patients with meningeal infiltration. Soluble CD4 in the CSF from healthy volunteers were below the detectable limit. We conclude that meningeal infiltration of CD4(+) ATL cells is strongly associated with elevated sCD4 levels in CSF, and some part of sCD4 in CSF may be originated from the native cells in the CNS as a response of inflammatory stimulations. Therefore, measurement of sCD4 may be useful in the diagnosis of meningeal infiltration and/or meningeal irritation in patients with ATL. © 1994 Wiley-Liss, Inc.     

Clinical significance of serum neuron-specific enolase in patients with adult T-cell leukemia

The present study examines the clinical significance of serum neuron-specific enolase (NSE) in patients with adult T cell-leukemia (ATL). Serum NSE values were measured using a radioimmunoassay in 35 patients (acute type, n = 15; lymphoma type, n = 10; chronic type, n = 10) and in 7 controls carrying T lymphotropic virus type-1 (HTLV-1). Serum NSE values >10 ng/mL were detected in 9 of 15 patients with acute type (60%), 5 of 10 with lymphoma type (50%), and in one of 10 patients with chronic type (10%) ATL, but in none of the HTLV-1 carriers. Contrary to previous findings demonstrating that 20% of patients with non-Hodgkin's lymphoma (NHL) had positive serum NSE, the frequency of a high NSE value in patients with acute and lymphoma type ATL was much higher (60% and 50%, respectively). The serum NSE value positively correlated with serum thymidine kinase activity (TK) and serum soluble interleukin-2 receptor (sIL-2R) levels (P < 0.04 and P < 0.01, respectively). Serum NSE values at the initial diagnosis were adversely related to overall survival time according to the log-rank test (P < 0.02). Pathological examinations demonstrated that both patients with anaplastic large cell lymphoma type ATL had cytoplasmic NSE and CD30 markers on cell membranes. These findings suggest that serum NSE is partially produced by ATL cells and that ATL tumor cells seem preferentially produce NSE compared with other NHL cells. Serum NSE may be a novel marker of disease aggressiveness as well as a prognostic factor for ATL.     

Leukemic cells from some adult T-cell leukemia patients proliferate in response to interleukin-4

The proliferative response of fresh peripheral blood leukemic cells from eight adult T cell leukemia (ATL) patients to interleukin-4 (IL-4) was studied to determine the possibility that the IL-4-mediated T-cell growth pathway is involved in the cell growth of leukemic cells in ATL. Resting lymphocytes from ten normal individuals did not proliferate in response to IL-4. Leukemic cells from two ATL patients did not respond to interleukin-2 (IL-2) or IL-4. Leukemic cells from two patients did respond to IL-2, but not to IL-4. In contrast, a strong proliferative response was observed in the IL-4 culture, but not in the IL-2 culture in the remaining four patients. Chromosome analysis of mitotic cells, performed in one of four patients, confirmed that the cells dividing in response to IL-4 were leukemic cells, but not activated normal lymphocytes. These results indicate the activation of IL-4/IL-4 receptor system in leukemic cells from some ATL patients and suggest the possible involvement of the system in the proliferation of leukemic cells and the leukemogenesis in ATL.     

Granulocyte-colony stimulating factor-induced proliferation of primary adult T-cell leukaemia cells

Granulocyte-colony stimulating factor (G-CSF) is known to induce proliferation and differentiation of granulocyte progenitors, and is widely used to treat neutropenia induced by intensive chemotherapy for malignant lymphoma or adult T-cell leukaemia/lymphoma (ATL). G-CSF is thought not to stimulate malignant lymphoid cells. In the present study we examined the ability of G-CSF to induce in vitro growth of primary ATL cells from 14 patients (nine acute-type, two chronic-type and three lymphoma-type), and we analysed the in vivo counts of ATL cells in patients who received G-CSF for neutropenia. FACS analysis using phycoerythrin-labelled recombinant G-CSF demonstrated that ATL cells from 11/14 patients express some G-CSF receptor (G-CSFR), with a range between 5.4% and 87.3%. Cells expressing G-CSFR also expressed CD4. Reverse polymerase chain reaction (PCR) analysis demonstrated expression of G-CSFR messenger RNA in G-CSFR expressing cells. Leukaemic cells derived from seven (four acute-type, one chronic-type and two lymphoma-type) of the 14 patients proliferated in vitro in response to G-CSF, as measured by [³H]thymidine incorporation; maximum responses were at G-CSF concentrations of 10–100 ng/ml. Nine of 14 patients receiving rG-CSF for neutropenia were analysed retrospectively for ATL cell numbers. Four patients whose primary tumour cells proliferated in response to rG-CSF in vitro showed a significant increase in ATL cell count after administration of rG-CSF ( P  =0.038), whereas five patients whose leukaemic cells did not proliferate in vitro showed no significant increase in ATL cell count. G-CSF can stimulate proliferation of ATL cells which may complicate therapy for this disease.     

Chromosomal abnormalities in adult T-cell leukemia/lymphoma (ATL)

Summary Chromosomal studies were performed on six patients with adult T-cell leukemia (ATL). Structural abnormalities of chromosome 3 were the most common. In one case a complete loss of the short arm of chromosome 10 (10 p-) was noted while in another case a balanced translocation involving chromosome 10 p and 4q was found. These abnormalities have not been previously reported. After reviewing the literature, it was concluded that chromosomes 3, 6, 10, 13, 14, and X were most frequently involved in abnormalities. Specific and consistent chromosomal abnormalities were noted in each study. Therefore, it is hypothesised that the mutation rate for this virus may be higher than first expected. Furthermore, the relative consistency of heterogenous findings in different localities may reflect a geographic clustering of specific chromosomal abnormalities which may in turn be related to specific and geographically associated viral mutations. To support these suggestions not only are more cytogenetic data required but a molecular evaluation of these patients must be carried out to establish a relationship, it any, between genetic abnormalities and the epidemiology of ATL.     

Interleukin-1 in multiple myeloma: producer cells and their role in the control of IL-6 production

We studied the role of interleukin (IL)-1β in patients with multiple myeloma. By in situ hybridization and immunochemistry, myeloid and megakaryocytic cells expressed high levels of the IL-1β gene and produced IL-1β. Myeloma cells less potently expressed the IL-1β gene and IL-1β protein. IL-1β gene expression was not constitutive since it was detected in the bone marrow myeloma cells of two patients, unlike circulating tumoural cells. In addition, nine myeloma cell lines failed to express the IL-1β gene and this expression could not be induced by 12 different cytokines. We demonstrated that IL-1 was mainly responsible for IL-6 production in the tumoural environment through a PGE₂ loop. In fact, an IL-1 receptor antagonist (IL-1RA) blocked PGE₂ synthesis and IL-6 production by 80%; this blockage could be reversed by adding synthetic PGE₂. Similar findings were found with indomethacin, an inhibitor of cyclooxygenase that blocks PGE₂ synthesis. Taken together, these data emphasize the possibility of blocking IL-1 by using IL-1RA or other antagonists in order to block IL-6 production, which is a major tumoural survival and proliferation factor.     

Immune responses and serum levels of cytokines in adult T-cell leukemia patients and human T-cell leukemia virus type-I carriers.

To find predictive parameters for development and progression of adult T-cell leukemia (ATL) in human T-cell leukemia virus type-I (HTLV-I) carriers, we investigated cellular immune responses such as mitogenic responses and natural killer activity of the peripheral blood mononuclear cells (PBMC). And serum or plasma levels of cytokines, including tumor-necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and immunosuppressive acidic protein (IAP), were also measured in patients with ATL, healthy HTLV-I carriers and healthy HTLV-I non-carriers as controls. Results are as follows: (1) increased spontaneous proliferation and decreased mitogenic responses of PBMC already existed in HTLV-I carriers; (2) IAP was significantly higher in patients with acute/lymphoma type ATL than in those with chronic/smoldering type, HTLV-I carriers and HTLV-I non-carriers. These results suggest that spontaneous proliferation or mitogenic responses and IAP may be useful parameters for the development and progression of ATL from the carriers. Since HTLV-I carriers already have various grades of immunosuppression, we should seriously try to prevent further HTLV-I transmission.