Chromosomal abnormalities define clonal proliferation in CD3- large granular lymphocyte leukemia.

Six patients with lymphoproliferative disorder of large granular lymphocytes (LDGL) were studied for chromosomal abnormalities. When the patients were divided into two groups depending on the expression of a mature antigen of T cell lineage, CD3, two with CD3+ phenotype had a stable disease, whereas three of the four patients with CD3- phenotype had marked hepatosplenomegaly and a highly aggressive disease. Chromosomal abnormalities were detected in four of six patients, indicating a clonal proliferation of large granular lymphocytes in individual patients. In particular, chromosomal abnormalities were found in three of the four patients with CD3- LDGL, all of which had a germ-line configuration of the T cell receptor beta-chain gene. Thus, the chromosomal abnormalities provide definitive evidence for the clonal origin of the expanded cells in the CD3- LDGL.