DIFFERENCES IN T-CELL-RECEPTOR GENE REARRANGEMENT AND TRANSCRIPTION IN NASAL LYMPHOMAS AT NATURAL-KILLER AND T-CELL TYPES - IMPLICATIONS ONCELLULAR-ORIGIN

Although nasal lymphomas showing midfacial destructive lesions had bee n classified as T-cell lymphomas, their exact cellular origin is still unclear. Although they usually express a restricted number of T-cell- related antigens, namely, CD2, CD43, and CD45RO, other pan-T or subset -T-lineage antigens, such as CD3 (membrane), CD5, CD4, CD8, and CD7, a re frequently absent. Conversely, they often express a natural killer (NK) cell-associated antigen, CD56, but lack other mature NK markers. To study their cellular origin further, the authors analyzed T-cell re ceptor (TCR) gene transcription in three cases of nasal lymphomas and correlated the findings with the phenotype and gene rearrangement data . Two cases of nasal lymphomas with CD2+CD3(Leu4)-CD19-CD56+ phenotype were shown to express truncated 1.0-kb T-beta and multiple unrearrang ed T-delta transcripts with germline TCR beta, gamma, delta, and immun oglobulin heavy-chain joining region (J(H)) genes, consistent with NK cell lineage. In contrast, one case of nasal lymphoma with CD2+CD3(Leu 4)+CD8+CD19-CD56+ phenotype expressed full-length T-alpha, T beta, and T-gamma transcripts with rearranged TCR beta, gamma, and deleted TCR delta genes, indicating T-cell lineage. These results support the view that nasal lymphomas can be separated into NK-cell and T-cell neoplas ms, based on differences in genotypic characteristics. The possibility of these tumors being derived from a putative common precursor cell m erits further investigation. Copyright (C) 1996 by W.B. Saunders Compa ny.