|Budget Amount *help
¥1,700,000 (Direct Cost : ¥1,700,000)
Fiscal Year 1995 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1994 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Clinicalphenotypicand genotypic features and the association with Epstein-Barr virus (EBV) of 18 patients with nasal T-cell lymphoma of lethal midline granuloma type (NTL-LMG) were investigated. The clinical features were characterized as prolonged fever (16 patients), widespread dissemination into distant sites (13 patients), and poor prognosis with median survival of only 6 months. EBV-encoded small nuclear early region (EBER) transcripts were identified in 16 of 18 patients. Monoclonal EBV genome, EBV-encoded nuclear antigen type 1 (EBNA1), and latent membrane protein type 1 (LMP1), were detected also in all EBER-positive cases tested. All 18 patients expressed pan-T antigens such as MT1, CD45RO,and/or CD2. The rearrangements of T-cell receptor (TCR)-beta, -gamma and/or -delta genes were shown in all 11 tumors tested. The natural killer (NK) cell phenotype, CD56, was expressed in all EBV-positive cases tested, and was not detected in EBV-negative cases. Seven EBV-positive cases expressed TCR-delta chain with rearranged TCR-gamma or -delta gene. While, all 2 EBV-negative cases corresponded to alphabetaT-cell lymphoma, which represented TCR-beta chain with rearranged TCR-beta gene. These data suggest that EBV-positive NTL-LMG may be derived from the lineage of NK-like T-cell or gammadeltaT-cells, and that EBV may play a role in the lymphomagenesis. Therefore, we propose that NTL-LMG which have peculiar clinical and histological features could be classified into a new lymphoma entity.