Large granular lymphocyte leukemia.

Clonal diseases of large granular lymphocytes (LGLs) represent a spectrum of clinically rare lymphoproliferative malignancies arising from either mature T-cell (CD3(+)) or natural killer (NK)-cell (CD3(-)) lineages. The clinical behavior of these disorders ranges from indolent to very aggressive. Patients with symptomatic indolent T-cell or NK-cell LGL leukemia are usually treated with immunosuppressive therapies; in contrast, aggressive T-cell or NK-cell LGL leukemias require intensive chemotherapy regimens. Novel targeted therapies are currently being tested in clinical studies.