Kiyoshi Watari

Identification of a melanoma antigen, PRAME, as a BCR/ABL-inducible gene

In order to elucidate molecular events in BCR/ABL‐induced transformation, we adopted a polymerase chain reaction (PCR)‐based technique of differential display and compared mRNA expression in human factor‐dependent cells, TF‐1, with that in factor‐independent cells, ID‐1, which were established from TF‐1 cells by transfection of BCR/ABL. Cloning and sequencing of a gene which was upregulated in ID‐1 cells revealed that the gene was identical to a melanoma antigen, PRAME. Our present study demonstrated that PRAME was markedly expressed in primary leukemic cells with chronic myeloid leukemia (CML) in blastic crisis and Philadelphia (Ph)+‐acute lymphoblastic leukemia (ALL), in which BCR/ABL played an important role as a pathogenic gene. Moreover, comparison of PRAME expression among CD34+ cells with CML in blastic, accelerated, and chronic phases revealed a higher expression in CML in advanced phases. Thus PRAME was considered to be a good candidate for a marker of Ph+‐leukemic blast cells as well as a new target antigen of leukemic blast cells that cytotoxic T cells can recognize.

Progress reports on immune gene therapy for stage IV renal cell cancer using lethally irradiated granulocyte-macrophage colony-stimulating factor-transduced autologous renal cancer cells

Abstract There is no effective treatment for patients with stage IV renal cell cancer (RCC), although the introduction of new therapy is imminent. Cancer gene therapy is currently considered to be one of the most promising therapeutic modalities in the field of cancer treatment. Based on the results of animal studies, vaccination using autologous granulocyte-macrophage colony-stimulating factor-transduced renal cancer cells appears promising. Before initiating a clinical study using an ex vivo gene-transduced autologous cell vaccine-based immunogene therapy for RCC in Japan, in 1992 we initially planned a Japanese version of a clinical protocol in collaboration with a US group. In 1993, the original protocol was refined. We performed five preclinical qualification studies using RCC nephrectomy specimens from patients in 1997, and the results showed that preparation of RCC cells for autologous vaccines at the Clinical Cell Technology Facility, Research Hospital of the Institute of Medical Science, University of Tokyo, was feasible. Subsequently in August 1998, the Ministry of Health and Welfare and the Ministry of Education, Science, Culture, and Sport approved our clinical protocol. We have recruited two patients with stage IV RCC to our study so far. Here we report the background to the initiation of cancer gene therapy in Japan.

Evaluation of engraftment by ABO genotypic analysis of erythroid burst-forming units after bone marrow transplantation.

Six patients received an allogeneic bone marrow transplant from HLA-identical ABO-mismatched donors. ABO genotype of erythroid burst-forming units (BFU-E) from peripheral blood was analyzed using polymerase chain reaction with sequence specific primers (PCR-SSP). After bone marrow transplantation (BMT), engraftment of donor cells by ABO genotypic analysis of BFU-E was compared with ABO phenotypic analysis of red blood cells (RBCs). During the early stage after BMT, ABO genotype of BFU-E in the recipients converted to that of the donors. In contrast, mixed ABO phenotype of RBCs persisted for about 3 months. In one patient, autologous hemopoietic cell recovery was detected by the ABO genotypic analysis before clinical manifestation. ABO genotypic analysis of BFU-E is relevant for enagraftment after ABO-mismatched BMT.

TCR-Vβ repertoire analysis with RT-PCR was useful for the early detection of pulmonary relapsed T-cell lymphoma after autologous peripheral blood stem cell transplantation

Pulmonary recurrence of malignant lymphoma is a rare event after stem cell transplantation. We report here a 45‐year‐old male who was successfully diagnosed with relapsed pulmonary T‐cell lymphoma using an RT‐PCR method. Clonal expansion of T cells expressing identical TCR V‐D‐J junction size (Vβ5‐Jβ1.5) was demonstrated in lymphocyte groups obtained from both bronchoalveolar lavage fluid at relapse, and paraffin embedded lymph node samples resected when he was first diagnosed with angioimmunoblastic T‐cell lymphoma. This method provided evidence to diagnose relapsed pulmonary angioimmunoblastic T‐cell lymphoma in its early phase. Am. J. Hematol. 64:124–127, 2000.