T-cell lymphoblastic leukemia/lymphoma syndrome with eosinophilia and acute myeloid leukemia

This case represents an example of an unusual T-cell lymphoblastic leukemia/lymphoma syndrome associated with eosinophilia and myeloid malignancy in a young boy. This case is one of only five reported "leukemic" variants of the disease and demonstrates the importance of considering this poor prognostic diagnosis in pediatric acute lymphoblastic leukemia. This case also illustrates the importance of an interactive multidisciplinary approach to the laboratory evaluation of a leukemia patient.

Identification of two new HLA-A*1101-restricted tax epitopes recognized by cytotoxic T lymphocytes in an adult T-cell leukemia patient after hematopoietic stem cell transplantation

We previously reported that Tax-specific CD8(+) cytotoxic T lymphocytes (CTLs), directed to single epitopes restricted by HLA-A2 or A24, expanded in vitro and in vivo in peripheral blood mononuclear cells (PBMC) from some adult T-cell leukemia (ATL) patients after but not before allogeneic hematopoietic stem cell transplantation (HSCT). Here, we demonstrated similar Tax-specific CTL expansion in PBMC from another post-HSCT ATL patient without HLA-A2 or A24, whose CTLs equally recognized two newly identified epitopes, Tax88-96 and Tax272-280, restricted by HLA-A11, suggesting that these immunodominant Tax epitopes are present in the ATL patient in vivo.

Construction of a minimal HIV-1 variant that selectively replicates in leukemic derived T-cell lines: towards a new virotherapy approach

T-cell acute lymphoblastic leukemia is a high-risk type of blood-cell cancer. We analyzed the possibility of developing virotherapy for T-cell acute lymphoblastic leukemia. Virotherapy is based on the exclusive replication of a virus in leukemic cells, leading to the selective removal of these malignant cells. We constructed a minimized derivative of HIV-1, a complex lentivirus encoding multiple accessory functions that are essential for virus replication in untransformed cells, but dispensable in leukemic T cells. This mini-HIV virus has five deletions (vif, vpR, vpU, nef, and U3) and replicated in the SupT1 cell line, but did not replicate in normal peripheral blood mononuclear cells. The stripped down mini-HIV variant was also able to efficiently remove leukemic cells from a mixed culture with untransformed control cells. In contrast to wild-type HIV-1, we did not observe bystander killing in mixed culture experiments with the mini-HIV variant. Furthermore, viral escape was not detected in long-term cultures. The mini-HIV variant that uses CD4 and CXCR4 for cell entry could potentially be used against CXCR4-expressing malignancies such as T-lymphoblastic leukemia/lymphoma, natural killer leukemia, and some myeloid leukemias.

[Graft-versus-ATLL effect induced by abrupt discontinuation of immunosuppression following allogeneic bone marrow transplantation]

A 46-year-old man was admitted to our hospital with swelling of a neck lymph node in June, 2002, and was diagnosed with adult T-cell leukemia/lymphoma (ATLL). As ATLL cells were detected in the peripheral blood after two courses of multi-agent chemotherapy (LSG 15), the treatment was changed to biweekly CHOP therapy. After two courses, hematological remission was achieved. Allogeneic bone marrow transplant (allo-BMT) from HTLV- negative and HLA-matched sibling donor was performed (conditioned with cyclophosphamide 60 mg/kg x 2 and total body irradiation 12 Gy). Cyclosporine A (CsA) and short-term methotrexate (MTX) were used for graft-versus-host disease prevention. Though the HTLV- provirus DNA (Southern blot) disappeared, HTLV-I provirus DNA (real-time PCR) T-cell receptor ygammachain gene rearrangement DNA (Southern blot) were detected in bone marrow after allo-BMT. MRD disappeared after the withdrawal of CsA. After the allo-BMT transplant, a graft-versus-ATLL (GVATLL) effect may be induced by abrupt discontinuation of immunosuppression.

Allogeneic stem-cell transplantation with reduced conditioning intensity as a novel immunotherapy and antiviral therapy for adult T-cell leukemia/lymphoma

Sixteen patients with adult T-cell leukemia/lymphoma (ATL) who were all over 50 years of age underwent allogeneic stem cell transplantation with reduced-conditioning intensity (RIST) from HLA-matched sibling donors after a conditioning regimen consisting of fludarabine (180 mg/m2), busulfan (8 mg/kg), and rabbit antithymocyte globulin (5 mg/kg). The observed regimen-related toxicities and nonhematologic toxicities were all found to be acceptable. Disease relapse was the main cause of treatment failure. Three patients who had a relapse subsequently responded to a rapid discontinuation of the immunosuppressive agent and thereafter achieved another remission. After RIST, the human T-cell leukemia virus type 1 (HTLV-1) proviral load became undetectable in 8 patients. RIST is thus considered to be a feasible treatment for ATL. Our data also suggest the presence of a possible graft-versus-ATL effect; an anti-HTLV-1 activity was also found to be associated with this procedure.

Tumor immunity against adult T-cell leukemia

Human T-cell leukemia virus type-I (HTLV-I) causes adult T-cell leukemia (ATL) in a small population of infected individuals after a long incubation period. Although the process of clonal evolution of ATL cells may involve multiple steps, ATL cells from half of the ATL cases still retain the ability to express HTLV-I Tax, a key molecule of HTLV-I leukemogenesis. A recent finding of reactivation of Tax-specific cytotoxic T lymphocytes (CTL) in ATL patients after hematopoietic stem cell transplantation suggests the presence of Tax expression in vivo and potential contribution of the CTL to antitumor immunity. This is consistent with the results of a series of animal experiments indicating that Tax-specific CTL limit the growth of HTLV-I-infected cells in vivo, although the animal model mimics only an early phase of HTLV-I infection and leukemogenesis. Establishment of an insufficient HTLV-I-specific T-cell response and an increased viral load in orally HTLV-I-infected rats suggests that host HTLV-I-specific T-cell response at a primary HTLV-I infection can be a critical determinant of persistent HTLV-I levels thereafter. These findings indicate that Tax-targeted vaccines may be effective for prophylaxis of ATL in a high-risk group, and also for therapy of ATL in at least half the cases.

Infection à BK Virus après allogreffe de celluleshématopoïétiques. A propos d'un cas

Polyomavirus hominis 1, better known as BK virus (BKV), infects up to 90% of the general population. Significant clinical manifestations can be seen in immunocompromised patients. We report a case of haemorragic cystitis likely due to BKV in a child after allotransplantation of hematopoietic stem cells. A 10-year old boy with poor-prognosis acute T lymphoblastic leukaemia underwent cord blood allogeneic stem cell transplantation while in his first relapse. Macroscopic haematuria and low back pain occurred by day 95, in the context of acute graft versus host disease and pulmonary aspergillosis. Histopathologic examination showed a cytopathogenetic effect consistent with the diagnosis of BKV infection. Urinary PCR was positive for BKV. Treatment with cidofovir was followed by a marked improvement of urinary symptoms. The current understanding, diagnosis, and treatment of BKV-associated infection is discussed.

Allogeneic hematopoietic stem cell transplantation provides sustained long-term survival for patients with adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is a distinct peripheral T-cell neoplasm that is highly resistant to chemotherapy. Several groups, including ours, have reported encouraging results of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with ATLL. To confirm our previous report and to establish the basis for a phase II clinical study, we analyzed 40 allo-HSCT for acute and lymphoma types of ATLL in seven institutions in Japan between 1997 and 2002. All evaluable cases entered complete remission (CR) after allo-HSCT and the median survival time was 9.6 months for all patients. The estimated 3-year overall and relapse-free survival, and disease relapse were 45.3, 33.8 and 39.3%, respectively. Among 10 cases with ATLL relapse, five cases achieved CR again: three by the reduction or cessation of immunosuppressive agents, which suggested a graft-versus-ATLL (GvATLL) effect. However, univariate or multivariate analysis did not show any benefit of graft-versus-host disease (GVHD) on the prevention of relapse. These results suggested that allo-HSCT was effective for some patients with aggressive ATLL, and that the GvATLL effect could be achieved even without GVHD. A new phase II trial to test the efficacy of allo-HSCT for ATLL is warranted.

Targeting promiscuous signaling pathways in cancer: another Notch in the bedpost

The chromosomal translocation t(7;9)(q34;q34.3) in human T-cell acute lymphoblastic leukemia results in the constitutive activation of Notch (Nic). Reported mutations in Ikaros cause the loss of DNA-binding, which in turn leads to a loss of repressive activity. Recently, these two mutations have been shown to cooperate in leukemogenesis. The current model proposes that the combination of the loss of Ikaros activity and the gain of constitutive Notch activity disrupts the normal balance between repression and activation at common regulatory elements. Furthermore, the model is extended to suggest that multiple transcription factors coordinate transcriptional repression and activation through these common regulatory elements. In leukemogenesis, the breakdown of this coordinate regulation underlies one of the pathophysiological mechanisms. Finally, using Notch as a template, potential points of interdiction by designer therapeutics are discussed.

[Eradication of adult T-cell leukemia cells and maintenance of remission by the graft-versus-leukemia effect after allogeneic bone marrow transplantation]

A 44-year-old man was referred to Hakodate Chuo Hospital because of progressive fatigue in April 2001, and was diagnosed as having adult T-cell leukemia (ATL; acute type). Complete remission was not obtained even with the application of multiple anti-leukemic agents including CHOP-V-MMV. The patient received an allogeneic bone marrow transplant from his HLA-identical, HTLV-I antibody-negative sibling donor in June 2002. The conditioning regimen consisted of cyclophosphamide, etoposide and total body irradiation. Cyclosporine A and a short course of methotrexate were given as prophylaxis for graft-versus-host disease (GVHD). Engraftment was achieved on day 16, while ATL cells were detected in the peripheral blood throughout the transplantation. ATL cells were also detected in bone marrow on day 20. Withdrawal of the immunosuppressant induced the eradication of the residual ATL cells in the peripheral blood on day 24 and in the bone marrow on day 40. Grade III of acute GVHD developed in the bowel on day 40, which lasted for over 5 months and was gradually resolved by administration of prednisolone and tacrolimus. The patient remains in complete remission 23 months after the transplantation. The clinical consequence of our case clearly shows that a graft-versus-leukemia (GVL) effect combined with graft-versus-host disease (GVHD) plays a curative role even in an early phase after bone marrow transplantation for patients with adult T-cell leukemia.

Activating Fc Receptors Are Required for Antitumor Efficacy of the Antibodies Directed toward CD25 in a Murine Model of Adult T-Cell Leukemia

We previously showed therapeutic efficacy of humanized anti-Tac (HAT), murine anti-Tac (MAT), and 7G7/B6 monoclonal antibodies, which recognize CD25, for human adult T-cell leukemia (ATL) in a murine model. In this study, we investigated the mechanism underlying the tumor-killing action mediated by these antibodies on an ATL model in nonobese diabetic/severe combined immunodeficient (SCID/NOD) wild-type mice that lack effective T and natural killer (NK) cells and in SCID/NOD Fc receptor common γ chain knockout (FcRγ−/−) mice. The ATL model was established by i.p. injection of human ATL cells (MET-1) into SCID/NOD wild-type or SCID/NOD FcRγ−/− mice. HAT, MAT, and 7G7/B6 were given to the leukemia-bearing mice at a dose of 100 μg weekly for 4 weeks. The three antibodies inhibited the leukemia growth significantly in SCID/NOD wild-type mice, as monitored by serum levels of human β2-microglobulin (P < 0.01), and prolonged survival of the leukemia-bearing SCID/NOD wild-type mice (P < 0.01) as compared with the control group. However, none of the antibodies manifested efficacy on the leukemia growth and survival of the SCID/NOD FcRγ−/− mice bearing MET-1 leukemia. In a pharmacokinetics study, the blood concentrations of the radiolabeled antibodies decreased with time similarly in SCID/NOD wild-type and SCID/NOD FcRγ−/− mice. Although NK cells may play a role in humans, in this murine model FcRγ receptors on non-NK cells, such as polymorphonuclear leukocytes or monocytes, are required for the tumor-killing action of the antibodies directed toward CD25.

Immunological risks of adult T-cell leukemia at primary HTLV-I infection

A small percentage of human T-cell leukemia virus type-I (HTLV-I)-infected individuals develop adult T-cell leukemia (ATL). In animal experiments, inoculation of HTLV-I via the oral route, which is the main route of mother-to-child viral transmission in humans as a result of breastfeeding, induced host HTLV-I-specific T-cell unresponsiveness and resulted in increased viral load. This strongly suggested that the known epidemiological risk factors for ATL (i.e. vertical HTLV-I infection and elevated viral load) are linked by an insufficient HTLV-I-specific T-cell response. Recent findings on the anti-tumor effects of Tax-targeted vaccination in rats and the reactivation of Tax-specific T cells in ATL patients as a result of hematopoietic stem cell transplantation imply promising immunological approaches for the prophylaxis and therapy of ATL.

Graft-versus-Tax response in adult T-cell leukemia patients after hematopoietic stem cell transplantation

Adult T-cell leukemia (ATL) caused by human T-cell leukemia virus type I (HTLV-I) is characterized by poor prognosis after chemotherapy. Recent clinical trials have indicated, however, that allogeneic but not autologous hematopoietic stem cell transplantation (HSCT) for ATL can yield better clinical outcomes. In the present study, we investigated cellular immune responses of ATL patients who obtained complete remission after nonmyeloablative allogeneic peripheral blood HSCT from HLA-identical sibling donors. In the culture of peripheral blood mononuclear cells (PBMCs) from a post-HSCT but not pre-HSCT ATL patient, CD8(+) CTLs proliferated vigorously in response to stimulation with autologous HTLV-I-infected T cells that had been established before HSCT in vitro. These CTLs contained a large number of monospecific CTL population directed to a HLA-A2-restricted HTLV-I Tax 11-19 epitope. The frequency of Tax 11-19-specific CD8+ CTLs in this patient markedly increased also in vivo after HSCT, as determined by staining with HLA-A2/Tax 11-19 tetramers. Similar clonal expansion of HTLV-I Tax-specific CTLs exclusively directed to a HLA-A24-restricted Tax 301-309 epitope was observed in the PBMCs from another ATL patient after HSCT from a HTLV-I-negative donor. Among four post-HSCT ATL patients tested, HTLV-I-specific CTLs were induced in the PBMC culture from three patients but not from the remaining one who had later recurrence of ATL. These observations suggested that reconstituted immunity against antigen presentation in ATL patients after HSCT resulted in strong and selective graft-versus-HTLV-I response, which might contribute to graft-versus-leukemia effects.

Adult T cell leukemia lymphoma

Adult T cell leukemia lymphoma (ATLL) is a CD4+ lymphoproliferative malignancy resulting from human T-cell leukemia virus type 1 (HTLV-1) infection. It includes differing clinical forms classified as smoldering, chronic, lymphomatous, and acute ATLL. The Tax protein of HTLV-1 has been implicated as a viral oncoprotein which enhances virus replication and alters cellular gene expression, including activation of nuclear factor kappa B (NF kB), to result in lymphoid transformation. Chemotherapy for ATLL has had limited efficacy with median survivals of about 1 yr. Antiviral therapy employing zidovudine and interferon has shown promising results, as have antibody-based therapies to the interleukin 2 (IL2) receptor. Novel approaches employ a combination of chemo/antiretroviral therapy, hematopoietic stem cell transplantation, or inhibitors of NF kB activation.

Gene expression profile of adult T-cell acute lymphocytic leukemia identifies distinct subsets of patients with different response to therapy and survival

Gene expression profiles were examined in 33 adult patients with T-cell acute lymphocytic leukemia (T-ALL). Nonspecific filtering criteria identified 313 genes differentially expressed in the leukemic cells. Hierarchical clustering of samples identified 2 groups that reflected the degree of T-cell differentiation but was not associated with clinical outcome. Comparison between refractory patients and those who responded to induction chemotherapy identified a single gene, interleukin 8 (IL-8), that was highly expressed in refractory T-ALL cells and a set of 30 genes that was highly expressed in leukemic cells from patients who achieved complete remission. We next identified 19 genes that were differentially expressed in T-ALL cells from patients who either had a relapse or remained in continuous complete remission. A model based on the expression of 3 of these genes was predictive of duration of remission. The 3-gene model was validated on a further set of T-ALL samples from 18 additional patients treated on the same clinical protocol. This study demonstrates that gene expression profiling can identify a limited number of genes that are predictive of response to induction therapy and remission duration in adult patients with T-ALL.