Izumi Masamoto

Reduced Frequency, Diversity, and Function of Human T Cell Leukemia Virus Type 1-Specific CD8+ T Cell in Adult T Cell Leukemia Patients

Human T cell lymphotropic virus type 1 (HTLV-1)-specific CTL are thought to be immune effectors that reduce the risk of adult T cell leukemia (ATL). However, in vivo conditions of anti-HTLV-1 CTL before and after ATL development have yet to be determined. To characterize anti-HTLV-1 CTL in asymptomatic HTLV-1 carriers (AC) and ATL patients, we analyzed the frequency and diversity of HTLV-1-specific CD8+ T cells in PBMC of 35 AC and 32 ATL patients using 16 distinct epitopes of HTLV-1 Tax or Env/HLA tetramers along with intracellular cytolytic effector molecules (IFN-γ, perforin, and granzyme B). Overall frequency of subjects possessing Tax-specific CD8+ T cells was significantly lower in ATL than AC (53 vs 90%; p = 0.001), whereas the difference in Env-specific CD8+ T cells was not statistically significant. AC possessed Tax11–19/HLA-A*0201-specific tetramer+ cells by 90% and Tax301–309/HLA-A*2402-specific tetramer+ cells by 92%. Some AC recognized more than one epitope. In contrast, ATL recognized only Tax11–19 with HLA-A*0201 and Tax301–309 with HLA-A*2402 at frequencies of 30 and 55%. There were also significant differences in percentage of cells binding Tax11–19/HLA-A*0201 and Tax301–309/HLA-A*2402 tetramers between AC and ATL. Anti-HTLV-1 Tax CD8+ T cells in AC and ATL produced IFN-γ in response to Tax. In contrast, perforin and granzyme B expression in anti-HTLV-1 CD8+ T cells of ATL was significant lower than that of AC. Frequency of Tax-specific CD8+ T cells in AC was related to proviral load in HLA-A*0201. These results suggest that decreased frequency, diversity, and function of anti-HTLV-1 Tax CD8+ T cell clones may be one of the risks of ATL development.

Augmentation of the activity of an immunotoxin, anti-Tac(Fv)-PE40KDEL, in T cell lines infected with human T cell leukemia virus type-I.

Therapy with an immunotoxin, anti-Tac(Fv)-PE38, which is a conjugate of the variable domains of an anti-Tac monoclonal antibody and Pseudomonas exotoxin, was reported to be useful for adult T cell leukemia (ATL) patients but a considerable amount of the immunotoxin is needed for the therapy and some side effects were also observed. We have previously demonstrated that an immunotoxin, anti-Tac(Fv)-PE40KDEL, showed strong cytotoxic effects on malignant cells from ATL patients. Therefore, we searched for agents that enhance the effects of the immunotoxin. PAK-200, FK-506, quinidine, cepharanthine and cyclosporine A (CsA) augmented the ability of the immunotoxin to inhibit protein synthesis in two human T cell leukemia virus type-I infected T cell lines, KUT-1 and KUT-2. CsA was the most potent agent in both the cell lines. Augmentation of the cytotoxic effect of the immunotoxin by these agents, especially CsA, may be useful in the immunotoxin therapy of ATL.

Aggressive NK cell leukaemia after splenectomy: association with CD95‐resistant memory T‐cell proliferation and recalcitrant clinical course of haemophagocytic syndrome

We describe a 44‐yr‐old Japanese woman with persistent polyclonal T‐cell proliferation and recalcitrant clinical course of haemophagocytic syndrome (HPS). T cells bearing αβ T‐cell receptors (TCR) expressed increased amounts of CD95 and of CD45RO, which are phenotypically memory T cells. The TCR repertoire was broad and diverse. Regardless of CD95 expression, these cells were resistant to CD95‐mediated apoptosis. Aggressive natural killer cell leukaemia (ANKL) without an association with Epstein–Barr virus was detected 1 month after therapeutic splenectomy that followed 3 yr of immunosuppressive therapy against HPS. The immunophenotype of these leukaemia cells was CD56, CD16dim, CD7, CD45RA and they expressed some CD2, CD8 and HLA‐DR. Moreover, hyperdiploid clones with complex chromosomal abnormalities were also detected. Latent NK‐cell malignancy seemed to cause the CD95‐resistant memory T‐cell proliferation and splenectomy resulted in overt ANKL progression. There should be careful consideration of the risks versus benefits of splenectomy in HPS, in light of the possibility of fatal leukaemia/lymphoma progression.

Successful bone marrow transplantation for children with aplastic anemia based on a best‐available evidence strategy

Okamoto Y, Kodama Y, Nishikawa T, Yamaki Y, Mougi H, Masamoto I, Tanabe T, Shinkoda Y, Kawano Y. Successful bone marrow transplantation for children with aplastic anemia based on a best‐available evidence strategy.
Pediatr Transplantation 2010: 14:980–985.

Clinical significance of CD70 expression on T cells in human T-lymphotropic virus type-1 carriers and adult T cell leukemia/ lymphoma patients

Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma (ATL). Miscellaneous host immune surveillance systems control T-cell growth/leukemogenesis during HTLV-1 infection. We characterized CD70 and CD27 expression on lymphocytes of HTLV-1 carriers and patients with ATL (study approved by the local Medical Ethical Committee). High CD70 expression was observed on CD4 + CD25+ T cells from patients with acute-type ATL, while patients with smoldering- or chronic-type ATL and HTLV-1 carriers exhibited lower expression. Furthermore, significantly higher CD27 expression was observed on HTLV-1-specific CTLs. We found an association between CD70 expression on CD4 + T cells and HTLV-1 infection; increased CD70 expression was observed after exposure to Tax. Moreover, addition of anti-CD70 antibodies enhanced the CD107a surface mobilization of HTLV-1 Tax-specific CTLs following Tax-peptide stimulation in the PBMCs of carriers. These data demonstrate the important role of the CD70/CD27 axis in immune responses in HTLV-1 carriers and ATL patients.

An unusual, CD4 and CD8 dual-positive, CD25 negative, tumor cell phenotype in a patient with adult T-cell leukemia/lymphoma

Nicholas Casey , Hiroshi Fujiwara, Taichi Azuma, Yuichi Murakami, Makoto Yoshimitsu, Izumi Masamoto, Yuichiro Nawa, Jun Yamanouchi, Hiroshi Narumi, Yoshihiro Yakushijin, Takaaki Hato and Masaki Yasukawa Department of Hematology, Clinical Immunology, and Infectious Diseases, Ehime University Graduate School of Medicine, Toon, Japan; Department of Hematology and Immunology, Kagoshima University Hospital, Kagoshima, Japan; Clinical Laboratory, Kagoshima University Hospital, Kagoshima, Japan; Division of Hematology, Ehime Prefectural Central Hospital, Matsuyama, Japan; Cancer Center of Ehime University Hospital, Ehime University Graduate School of Medicine, Toon, Japan; Department of Blood Transfusion and Cell Therapy, Ehime University Graduate School of Medicine, Toon, Japan

Sézary syndrome in an anti-human T-cell lymphotropic virus type 1 seropositive carrier

Dear Editor, An 84-year-old man, seropositive for human T-cell lymphotropic virus type 1 (HTLV-1), was referred to our clinic because of erythroderma (Fig. 1a,b). Multiple enlarged lymph nodes (≤2 cm) were palpable in the axilla and inguinal area. A skin biopsy specimen from his back showed perivascular infiltration of atypical lymphoid cells in the upper dermis (Fig. 1c, d). Immunohistochemical examination revealed that most cells were strongly CD3and CD4-positive with partial CD25 positivity, and a few were CD8(Fig. 1e–h) and CD20-positive. Inguinal lymph node biopsy showed dermatopathic lymphadenopathy. Serological tests using enzyme-linked immunoassay and western blotting yielded positive results for anti-HTLV-1 antibody. The leukocyte count was 10 023/lL, with 53% abnormal lymphoid cells with cerebriform nuclei, containing 84% CD4-positive cells, and the CD4/CD8 ratio was elevated (31). CD4CD7 and CD4CD26 cells constituted 90% and 93% of lymphoid cells, respectively. Southern blot analysis revealed a monoclonal T-cell receptor-Cb1 rearrangement in peripheral blood mononuclear cells (PBMC) but not in enlarged lymph nodes. Albumin-adjusted calcium (9.3 mg/dL) and blood urea nitrogen (21.9 mg/dL) were within normal limits. Serum lactate dehydrogenase and albumin levels were elevated (403 IU/L; normal, 124–222) and slightly below normal (3.9 g/dL; normal, 4.1–5.1), respectively. Serum soluble interleukin-2 receptor was elevated (2318 U/mL; normal, 127–582). On flow cytometry, CD4/CD25 double-positive cells comprised 44% of lymphoid cells, whereas the CD25 fluorescence intensity was medium (Fig. 1i), and cells positive for cell adhesion molecule 1, a cell surface marker for adult T-cell leukemia/lymphoma (ATLL), accounted for only 1% of lymphocytes. These findings excluded a diagnosis of ATLL. Furthermore, monoclonal HTLV-1 integration was not detected on Southern blot, and HTLV-1 proviral DNA copy number was 0.1/1000 PBMC. Therefore, we arrived at a diagnosis of S ezary syndrome (SS, T4N1M0B2, stage IVA1) in a HTLV-1 carrier without ATLL, and started treatment with 200 mg/day vorinostat, which was reduced to 100 mg after a month because of adverse effects such as fatigue, diarrhea and thrombocytopenia. Because the reduced-dose vorinostat showed limited effectiveness, the patient was started on bexarotene and his symptoms were well controlled at 24 months from his first visit. Distinguishing SS in HTLV-1 seropositive patients from ATLL with erythroderma is critical because, despite having similar clinical symptoms, they have markedly different prognosis and treatment strategies. With an ATLL diagnosis, the present case would have been classified as chronic type ATLL with poor prognosis; moreover, erythrodermic ATLL has poor outcomes. Hence, the patient would have been treated with combination chemotherapy with cytotoxic agents. In SS cases, chemotherapy decreases the median time to next treatment, and multi-agent chemotherapy often induces immunosuppression, increasing the risk of serious infection and poor tolerance. Therefore, chemotherapy should only be used when other treatment options have been tried and become ineffective. We were able to treat SS in this HTLV-1 seropositive patient successfully without combination chemotherapy. This case highlights the importance of the precise diagnosis of lymphoma in HTLV-1 seropositive patients by performing molecular biological examination to evaluate HTLV-1 monoclonal integration into the genomic DNA of host T cells.