Decade-long WT1-specific CTLs induced by WT1 peptide vaccination.

INTRODUCTION: The peptide-based cancer vaccine targeting Wilms' tumor 1 (WT1) is a promising immunotherapeutic strategy for hematological malignancies. It remains unclear how long and to what extent the WT1-specific CD8 + cytotoxic T cell (CTL) persist after WT1 peptide vaccination. METHODS: The WT1 peptide vaccine was administered with written consent to a patient with CML in the chronic phase who did not respond well to imatinib, and the patient was followed for 12 years after vaccination. Immune monitoring was performed by specific amplification of WT1-specific CTLs using a mixed lymphocyte peptide culture. T-cell receptors (TCRs) of amplified WT1-specific CTLs were analyzed using next-generation sequencing. This study was approved by the Institutional Review Board of our institution. RESULT: WT1-specific CTLs, which were initially detected during WT1 peptide vaccination, persisted at a frequency of less than 5 cells per 1,000,000 CD8 + T cells for more than 10 years. TCR repertoire analysis confirmed the diversity of WT1-specific CTLs 11 years after vaccination. CTLs exhibited WT1 peptide-specific cytotoxicity in vitro. CONCLUSION: The WT1 peptide vaccine induced an immune response that persists for more than 10 years, even after cessation of vaccination in the CML patient.

[Effective combination chemotherapy with rituximab for acute lymphoblastic leukemia with bone relapse after bone marrow transplantation].

A 26-year-old woman with acute lymphoblastic leukemia (ALL) relapsed three times after HLA-matched related bone marrow transplantation. Initially, ALL relapsed in the central nervous system (CNS) 1 year after transplantation. Then, ALL relapsed as a single bone tumor involving the CNS and pelvis 4 years after transplantation. Finally, multiple bone tumors in the pelvis and lumbar bones were found as well as spread to the bone marrow 5 years after transplantation. Bone marrow aspiration also showed ALL relapse. Flow cytometry analyses detected CD20-positive cells in the bone tumor. Though the initial bone tumor was resistant to hyper CVAD, radiation was effective and this patient achieved complete remission. At that time, the total radiation dose had already reached the upper limit. After the third relapse, bone marrow achieved complete remission with the administration of pirarubicin, vincristine, prednisolone, and L-asparaginase (arranged DVP-L), though this combination chemotherapy itself was not effective in multiple bone tumors. Thereafter, arranged DVP-L plus rituximab was administered, which resulted in significant tumor reduction. Biweekly rituximab administration as maintenance therapy has completely prevented the regrowth of bone tumors. Rituximab for relapsed CD20-positive ALL patients after stem cell transplantation could be beneficial.

Identification of an overexpressed gene, HSPA4L, the product of which can provoke prevalent humoral immune responses in leukemia patients.

OBJECTIVE: To identify leukemia-associated antigens, we applied the serological identification of antigens by the recombinant expression cloning (SEREX) method to a chronic myelogenous leukemia (CML) patient who achieved a cytogenetic response to interferon-alpha. MATERIALS AND METHODS: Immunoscreening of the cDNA library was performed with sera from a CML patient. Two isolated antigens were used to evaluate the expression pattern using Northern blot analysis and quantitative reverse transcriptase polymerase chain reaction. Western blotting and enzyme-linked immunosorbent assay were also performed for serological analysis. RESULTS: We identified 14 positive clones, representing five different antigens. Of these, two genes were further validated. One (clone 70) was the human polyribonucleotide nucleotidyltransferase 1 (PNPT1), which is the type I interferon (alpha/beta-responsive gene). The mRNA of clone 70 was ubiquitously expressed in normal human tissues. The other gene (clone 57) was the heat shock 70-kDa protein 4-like (HSPA4L), which is a member of the heat shock protein 110 family, whose mRNA is strongly expressed in normal human testis and overexpressed in leukemia cells. Seroactivity against HSPA4L was detected in 6 of 9 acute myeloid leukemia patients, 4 of 10 acute lymphoblastic leukemia patients, 9 of 11 CML patients, and none of 10 healthy volunteers. Leukemia patients had higher titer of the antibodies against the protein than healthy volunteers. CONCLUSIONS: These results suggest that HSPA4L, a member of heat shock protein, is highly expressed by leukemia cells, and elicit humoral immune responses in leukemia patients, and it might be a potential target for antileukemia therapy and an antigen-specific immunotherapy for leukemia.

[Successful treatment of POEMS syndrome with high-dose chemotherapy and autologous peripheral blood stem cell transplantation].

A 42-year-old woman presented with pericardial and pleural effusion, ascites and para-aortic lymphadenopathy of unknown etiology. Six months later she was admitted with fever, pain and motor disturbance of lower limbs, and exacerbation of the effusion, ascites and edema. Physical examination showed hepatosplenomegaly, skin pigmentation and hypertrichosis. Immunoelectophoresis revealed monoclonal IgA-lambda protein in the serum and Bence-Jones protein-lambda in the urine. Bone marrow aspiration showed a mild increase of atypical plasma cells. Vascular endothelial growth factor (VEGF) had markedly increased to 10,900 pg/ml. Electromyography showed changes suggestive of demyelination. These clinical features were consistent with the diagnosis of POEMS syndrome. VAD chemotherapy was not effective for the effusion and neuropathic deterioration. After control of the massive pleural effusion by chest tube drainage, peripheral blood stem cell (PBSC) collection was performed with cyclophosphamide and G-CSF. The patient received melphalan 100 mg/m2 on 2 consecutive days and the PBSC were infused 2 days later. The bone marrow recovered rapidly and the pericardial and pleural effusion disappeared completely. Her performance status markedly improved from a bedridden state. High-dose melphalan with auto-PBSCT should be investigated further as a recommended therapy for POEMS syndrome.

Successful treatment of adult T-cell leukemia with unrelated cord blood transplantation.

This study reports the first well-documented case of adult T-cell leukemia (ATL) successfully treated with unrelated cord blood transplantation (UCBT). A 49-year-old woman was diagnosed with acute-type of ATL. Chemotherapy induced complete remission, but the human T-cell leukemia virus type 1 (HTLV-1) proviral load was detected in mononuclear cells of her peripheral blood. The patient received UCBT with a conditioning regimen consisting of total body irradiation, cytarabine, and cyclophosphamide. She remains in remission 30 months after UCBT and the HTLV-1 proviral load has fallen to undetectable levels. This result suggests that UCBT should be a therapeutic option for ATL patients who do not have suitable donors and those who urgently require treatment.

Plasma brain natriuretic peptide during myeloablative stem cell transplantation.

OBJECTIVE: Cardiovascular complication is one of the serious complications in stem cell transplantation (SCT). We measured plasma brain natriuretic peptide (BNP) concentrations in patients who received SCT to evaluate possible cardiac toxicity of the regimens employed in SCT. PATIENTS: Ten patients with allogeneic SCT and 5 patients with autologous SCT using myeloablative conditioning regimens were enrolled. The preparative chemotherapy for 8 patients with allogeneic SCT included cyclophosphamide (60 mg/kg i.v. for 2 days) and other drugs and that for autologous SCT included cyclophosphamide (50 mg/kg for 2 days) and other drugs. Total body irradiation (TBI) was employed only in the patients who received allogeneic SCT. METHOD: Plasma BNP was measured using a radioimmunoassay for human BNP before and after SCT. RESULTS: In 13 of 15 patients, BNP levels were elevated after SCT. In patients who received a total body irradiation (TBI) of 13.2 Gy, BNP levels were higher than those without irradiation (p=0.01). The BNP level reached a peak within 6 months after SCT in most patients and fell thereafter. But 7 of the 15 patients (46.7%) had an abnormally high level of plasma BNP even after 6 months of SCT which suggests subclinical myocardial damage. CONCLUSION: A rise in plasma BNP was frequently observed after SCT, and may be considered to represent cardiac damage caused by the preparative chemotherapy and/or total body irradiation. Since a rise was noted 6 months after SCT, long-term evaluation of cardiac function is important.