Foxp3 expression on normal and leukemic CD4+CD25+ T cells implicated in human T-cell leukemia virus type-1 is inconsistent with Treg cells

Foxp3 is a master gene of Treg cells, a novel subset of CD4⁺ T cells primarily expressing CD25. We describe here different features in Foxp3 expression profile between normal and leukemic CD4⁺CD25⁺ T cells, using peripheral blood samples from healthy controls (HCs), human T-cell leukemia virus type-1 (HTLV-1)-infected asymptomatic carriers (ACs), patients with adult T-cell leukemia (ATL), and various hematopoietic cell lines. The majority of CD4⁺CD25⁺ T cells in HCs were positive for Foxp3, but not all CD4⁺CD25⁺ T cells in ACs were positive, indicating that Foxp3 expression is not always linked to CD25 expression in normal T cells. Leukemic (ATL) T cells constitutively expressing CD25 were characteristic of heterogeneous Foxp3 expression, such as intra- and inter-case heterogeneity in intensity, inconsistency with CD25 expression, and a discrepancy in the mRNA and its protein expression. Surprisingly, a discernible amount of Foxp3 mRNA was detectable even in most cell lines without CD25 expression, a small fraction of which was positive for the Foxp3 proteins. The subcellular localization of Foxp3 in HTLV-1-infected cell lines was mainly cytoplasmic, different from that of primary ATL cells. These findings indicate that Foxp3 has two facets: essential Treg identity and molecular mimicry secondary to tumorigenesis. Conclusively, Foxp3 in normal T cells, but not mRNA, is basically potent at discriminating a subset of Treg cells from CD25⁺ T-cell populations, whereas the modulation of Foxp3 expression in leukemic T cells could be implicated in oncogenesis and has a potentially useful clinical role.     

Functional diversity within the suppressor phenotype as defined by monoclonal antibody in T-cell prolymphocytic leukemia

A patient with T-cell prolymphocytic leukemia (T-PLL) is described. The malignant T-cells from the patient were predominantly Leu-2-positive, indicating a suppressor phenotype. The cells were then tested to determine their functional capabilities. The patient's Leu-2-positive cells initially suppressed B-cell proliferation, as predicted by their phenotype but later functioned as T helper cells in the pokeweed mitogen system without a change in phenotype. The cells also responded inadequately to alloantigen and mitogen despite addition of exogenous T-cell growth factor (TCGF). Leu-2-positive prolymphocytes from the spleen of the patient were constitutive producers of TCGF. Surface phenotype using monoclonal antibody was inadequate to predict T-cell function of the cells from this patient with T-PLL. In addition, these data suggest there may be functional subpopulations within the OKT8+ phenotype. Constitutive TCGF production by malignant post-thymic T-cells may represent a mechanism by which these cells sustain their own growth.     

The time-sequential changes of risk factors for adult T-cell leukemia development in human T-cell leukemia virus-positive patients with rheumatoid arthritis: a retrospective cohort study

Abstract

Objective: This study aimed to investigate the time-sequential changes of risk factors for adult T-cell leukemia (ATL) development in human T-cell leukemia virus type 1 (HTLV-1)-positive rheumatoid arthritis (RA) patients.

Methods: HTLV-1 infection was screened using particle agglutination assay and confirmed via western blotting in 365 RA patients. Twenty-three HTLV-1-positive RA patients were included in the study cohort. Blood samples were obtained from these patients at each observation time point. The values of HTLV-1 proviral load (PVL) and serum soluble IL-2 receptor (sIL2-R), which are risk factors for ATL development, were measured using real-time PCR and enzyme immunoassay, respectively.

Results: The study cohort comprised 79 person-years. The median HTLV-1 PVL and sIL2-R values of the HTLV-1-positive RA patients were 0.44 copies per 100 white blood cells (WBCs) and 406?U/mL, respectively. Three HTLV-1-positive RA patients showed a high PVL value. No remarkable changes were observed in the PVL and sIL2-R values during the observation period. However, one elderly HTLV-1-positive RA patient who had a high PVL value developed ATL during treatment with methotrexate and infliximab.

Conclusion: A thorough clinical assessment of the risk factors for ATL development may be necessary in daily clinical practice for RA patients in HTLV-1-endemic areas in Japan.     

Therapy with CD7 monoclonal antibody TH-69 is highly effective for xenografted human T-cell ALL

Human T-cell acute lymphocytic leukaemia (ALL) was established in athymic nude or severe combined immunodeficient (SCID) mice by injecting CEM or MOLT-16 cells. When nude mice bearing approx. 2 g of tumour were treated with a single injection of CD7 antibody TH-69, 82.6% reached complete remission within 10 d whereas 13.0% showed partial remission. Similarly, in SCID mice with advanced disease a significant prolongation of survival was seen. The therapeutic effects were dependent upon dose and affinity of the antibody. TH-69 is a high-affinity antibody (7.6 × 10⁹  M ⁻¹) that rapidly induced modulation during treatment. The Fc-portion of the antibody was required for effective tumour cell killing. Complement deposition was found on tumour sections after TH-69 treatment and in part may account for tumour destruction. There was no evidence for antibody-dependent cellular cytotoxicity (ADCC). The kinetics of tumour disappearance suggested the initiation of a programmed cell death (PCD), despite the lack of significant DNA fragmentation. Unmodified high-affinity antibodies to the T-cell antigen CD7 have potential for T-cell ALL therapy.     

Immunoelectron microscopic demonstration of antigenic sites on lymphoid cells using a human monoclonal antibody (Ha6D3)

The reactivity of a human monoclonal antibody directed against human B and T lymphocytes was tested for the first time at the ultrastructural level. The antigenic sites detected by this antibody were localized on the surface membrane of lymphocytes and, to a lesser extent, in the cytoplasm on membranes of the endoplasmic reticulum and perinuclear envelop of some centroblasts and immunoblasts. Ultrastructural demonstration of target antigen detected by human monoclonal antibodies may be important prior to therapeutic application of these antibodies.     

Flow cytometric analysis of T and Tn epitopes on chronic lymphocytic leukemia cells

Immunophenotyping of peripheral blood lymphocytes from six patients with B-cell chronic lymphocytic leukemia (B-CLL) and five normal volunteers was done and their T and Tn epitopes analyzed using specific monoclonal antibodies and flow cytometry. Lymphocytes from all patients showed strong Tn expression as compared to normal control lymphocytes. By contrast, T antigen was not expressed. The Tn expression may be a useful diagnostic and prognostic marker for B-CLL. © 1996 Wiley-Liss, Inc.     

Diffuse panbronchiolitis as a pulmonary complication in patients with adult T-cell leukemia

Forty-three cases of adult T-cell leukemia (ATL) admitted to our hospital between 1982 and 1987 were studied. Three of those were found to be complicated with diffuse panbronchiolitis (DPB). The incidence of DPB is considered to be significantly higher in patients with ATL. The three DPB-complicated cases composed one case each of the smoldering, chronic, and acute type of ATL. In each type, DPB preceded overt ATL and Candida albicans was found in sputa following detection for bacteria. The DPB complication apparently worsened the prognosis of the ATL patients. We have discussed a possible relationship between ATL and DPB.     

Association of human T-cell leukemia virus type 1 with prevalent rheumatoid arthritis among atomic bomb survivors: A cross-sectional study

Previous studies have suggested that human T-cell leukemia virus type 1 (HTLV-1) might act as a pathogen in rheumatoid arthritis (RA), but epidemiological evidence of an association is scarce. We measured anti-HTLV-1 antibodies among Nagasaki atomic bomb survivors to determine whether HTLV-1 is related to RA and whether radiation exposure is associated with HTLV-1 and RA prevalence.This is a cross-sectional study among atomic bomb survivors who participated in biennial health examinations from 2006 to 2010. Serum levels of anti-HTLV-1 antibodies were measured using a chemiluminescent enzyme immunoassay and confirmed by Western blotting. Association between HTLV-1 and RA was analyzed by a logistic regression model.Of 2091 participants (women 61.5%; median age, 73 years), 215 (10.3%) had anti-HTLV-1 antibodies. HTLV-1 prevalence was higher among women (13.1% vs 5.8%; P < .001). Twenty-two participants (1.1%) were diagnosed with RA. HTLV-1 prevalence among RA participants was significantly higher than that among non-RA participants (27.3% vs 10.1%; P = .020). After adjustment for age, sex, and hepatitis C virus infection, HTLV-1 was significantly associated with prevalent RA (odds ratio, 2.89; 95% confidence interval, 1.06, 7.03). There was no association between radiation dose and either the prevalence of HTLV-1 or RA.This study, among a well-defined group of atomic bomb survivors, suggests that HTLV-1 is associated with RA.     

Frequent lack of antibodies against human T-cell leukemia virus type I gag proteins p24 or p19 in sera of patients with adult T-cell leukemia

Summary Specificities of antibodies against human T-cell leukemia virus type I (HTLV-I) in sera of 27 patients with adult T-cell leukemia (ATL) were studied. All sera were positive for HTLV-I antigens by immunofluorescence assay using cells expressing HTLV-I antigens; sera from five ATL patients, however, did not react or hardly reacted with p19 or p24 gag proteins of HTLV-I upon immunoprecipitation assay. Therefore, the relationships among antibody specificities against HTLV-I, the proviral structures of HTLV-I genomes in leukemic cells, and the expression of viral antigens by leukemic cells after cultivation in vitro for a few days were examined. Analyses of the genomic structures of the proviruses revealed deletions in at least seven cases. However, we could not detect deletions in the proviral genomes of four out of the five ATL patients who lacked antibodies against gag proteins. Furthermore, expression of p19 and p24 was detected in these patients' peripheral blood lymphocytes (PBL) cultured in vitro for a few days. Thus, some ATL patients could not or could hardly raise antibodies against gag proteins, although they harbored complete HTLV-I genomes and their PBL expressed gag proteins in vitro. All patients harboring deleted proviruses, so far tested, raised antibodies not only against viral proteins that should be encoded by the integrated proviruses, but also against viral proteins that should be encoded by the deleted regions. Antibodies against viral proteins were detected also in sera of ATL patients whose PBL did not express viral proteins after in vitro cultivation. Specificities of antibodies against viral proteins in ATL patients could not be predicted by the structures of proviruses in leukemic cells or by expression of viral proteins in vitro. Immune responses to HTLV-I antigens were weak or lost in some ATL patients.Abbreviations used HTLV-I human T-cell leukemia virus type I - ATL adult T-cell leukemia - PBL peripheral blood lymphocytes - PAGE Polyacrylamide gel electrophoresis - kb kilobases Supported in part by a grant-in-aid from the Ministry of Health and Welfare of Japan for a comprehensive 10-year strategy for cancer control, and a grant-in-aid from the Ministry of Education, Science and Culture of Japan     

Treatment of adult T-cell leukemia/lymphoma: past, present, and future

Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell malignancy caused by human T-cell lymphotrophic virus type I. Clinical manifestations of ATLL range from smoldering to chronic, lymphoma and acute. Patients with acute and lymphoma type ATLL require therapeutic intervention. Conventional chemotherapeutic regimens used against other malignant lymphoma have been administered to ATLL patients, but the therapeutic outcomes of acute and lymphoma type ATLL remain very poor. Promising results of allogeneic stem cell transplantation (SCT) for ATLL patients have recently been reported and the treatment outcome might be improved for some ATLL patients. Besides conventional chemotherapy and SCT, interferon, zidovudine, arsenic trioxide, targeted therapy against surface molecule on ATLL cells, retinoid derivatives, and bortezomib have been administered to ATLL patients in pilot or phase I/II studies. Further studies are required to confirm the clinical benefits of these novel therapeutics. This article reviews the current status and future directions of ATLL treatment.     

Adult T-cell leukemia/lymphoma with two distinct clones in the peripheral blood and lymph node

A case of adult T-cell leukemia/lymphoma (ATL) with two different clones in the peripheral blood and lymph nodes is reported here. When cellular DNA from the lymph node was digested with EcoRI, one band larger than 9 Kb was detected. Digestion of the cellular DNA with PstI resulted in one clear band in addition to three internal fragments. In contrast, when cellular DNA from malignant peripheral blood lymphocytes (PBL) was digested with the same endonucleases, distinct bands at positions different from those observed in the lymph node were detected, indicating two separate malignant clones in the patient. Monoclonality of the tumor cells was shown by T-cell receptor-β (TCR-β) gene rearrangement in both PBL and lymph node. Furthermore, there was a difference in the surface phenotype between tumor cells taken from peripheral blood (CD4+, CD8–) and lymph node (CD4+, CD8+). These findings suggest the presence of two different ATL clones in PBL and lymph node in a single patient simultaneously, which is distinguishable by the integration pattern of human T-cell leukemia virus type I (HTLV-I) proviral DNA.     

Dual rearrangement of immunoglobulin and T-cell receptor gene in a case of T-cell hairy-cell leukemia.

We report a case of T-cell hairy-cell leukemia with a dual rearrangement of Ig- and T-cell receptor genes. The cytochemical, transmission electron microscopy, and surface antigens data (CD3+, CD8+, CD11+, HLA-DR+, CD19-, CD20-) were consistent with a T-cell hairy-cell leukemia. Molecular analysis according to Southern revealed a dual rearrangement of immunoglobulin heavy-chain (JH) and T-cell receptor beta (TcR beta) chain genes. Our findings suggest that the coexistence of JH and TcR gene rearrangements, frequently detected in acute leukemia, may also be observed in hematologic malignancies derived from more differentiated cells.     

Major prognostic factors of Japanese patients with lymphoma-type adult T-cell leukemia

Fifty-three Japanese patients with the lymphoma-type adult T-cell leukemia (ATL) were analyzed to study the prognostic value of various clinical findings recorded at the time of diagnosis. All patients were positive for human T-cell leukemia virus type I (HTLV-I) antibody and demonstrated monoclonal integration of HTLV-I proviral DNA in their malignant cells. The important individual variables detected in a previous univariate analysis were placed in a multiple regression model to identify the major prognostic factors for survival. This analysis showed that serum lactate dehydrogenase (LDH), calcium, and total protein levels had a strong predictive relationship with the length of survival (in descending order of importance). Among the 53 patients, 46 were dead at the time of analysis. The cause of death in relation to the duration of survival is also reviewed in this article.     

A novel monoclonal antibody specific for human pre-B cell leukemia/lymphoma

A novel monoclonal antibody, designated WH14-antibody (WH14-Ab), was produced by using a non-T ALL cell line (HBL-3) as an immunogen. 35S-labelled immunoprecipitate revealed that the antigen reacting with WH14-Ab was estimated to be 30 Kd. Immunoglobulin isotype of WH14-Ab was IgG1. In the normal hematopoietic tissue, WH14-Ab reacted with a small number of monocytes (less than 30%) in the peripheral blood, but neither with the lymphocytes nor granulocytes. WH14-Ab reacted with HBL-3 and REH, but not with other B-cell leukemia/lymphoma and EBV-transformed cell lines. In addition, WH14-Ab reacted with most non-T ALL and pre-B lymphoblastic lymphoma. WH14-Ab did not react with all T-cell lymphomas. These findings indicate that the WH14-Ab may recognize the cell surface determinant shared by immature B cells, especially pre-B cells, in the B-cell lineage. WH14-Ab may be useful not only for the detection of pre-B cell leukemia/lymphomas but also for the investigation of maturation and differentiation of B-cell lineage.     

Transient response of pure red cell aplasia to anti-thymocyte globulin in a patient with T-cell chronic lymphocytic leukemia

Pure red cell aplasia (PRCA) is an unusual complication of chronic lymphoproliferative disorders. A patient with T-cell chronic lymphocytic leukemia (T-CLL) had severe anemia and neutropenia. Initial in vitro studies demonstrated no evidence of T-cell suppression of erythropoiesis. Sequential bone marrow examinations demonstrated progressive red cell aplasia. In vitro studies showed that the T-cells from the patient suppressed allogeneic but not autologous BFU-E. Treatment with antithymocyte globulin (ATG) reduced circulating leukemic cells and produced a definite but transient improvement in erythropoiesis.     

A human T-cell antigen defined by xenoantiserum to Sézary leukemic cells: immunochemical and functional studies

Xenoantiserum to Sézary cell leukemia cells (ASS) was developed by immunizing rabbits with those cells and was absorbed with human red cells, liver, tonsil B cells, and cultured Raji cells. This reagent reacted by immunofluorescence with virtually all human thymus and T cells. In the thymus, medullary cells reacted more strongly with ASS than did cortical thymocytes. When immunoprecipitates that formed between ASS and 125I-labeled lymphocyte surface glycoproteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was found that ASS precipitated a 72K molecular weight (MW) glycoprotein from T cells but not from B cells. On the one hand, it was shown by functional studies that T cells sensitive to the cytotoxic effect of ASS contained T cells that could aid the immunoglobulin synthesis of B cells induced by pokeweed mitogen. On the other hand, suppressor T cells induced by concanavalin A resided in those cells rather resistant to its cytotoxic effect. These data support the idea that the 72K MW glycoprotein on human thymus and T cells might be homologous to mouse Lyt-1 antigens.