MALIGNANT T-GAMMA/DELTA LYMPHOPROLIFERATIVE DISEASE WITH NATURAL-KILLER LYTIC ACTIVITY

A 17-year-old girl presented with a lymphoproliferative disease involving the bone marrow, peripheral blood, and liver associated with reactive hyperplasia of the spleen. Neoplastic cells were atypical medium-sized lymphoblasts with convoluted nuclei and nucleoli without features of large granular lymphocytes (LGL). The phenotype was CD3+CD4-CD8-, TCR-alpha/beta-, TCR-gamma/delta+, delta-TCS1- and CD16+, and these cells exhibited spontaneous natural killer (NK) activity. DNA analysis showed rearrangement of the TCR-gamma gene but not of TCR-beta or of Ig-mu-genes. This unusual lymphoproliferative disease may represent the neoplastic expansion of a minor subset of normal T-gamma/delta cells with NK activity.