[Large granular lymphocytic leukemia]

We investigated the surface markers, cell-function, clonality, and the association of IL-2 receptors and a second messenger of src family of tyrosine kinase p56lck in IL-2 signal transduction of the leukemic cells of 12 patients with large granular lymphocytic leukemia (LGL leukemia). The leukemic cells of 5 patients were CD3+ and 5 of them were CD3-. In three patients with CD3- leukemia examined, one showed karyotype abnormality of 46, XY, -10, +mar and the delta gene of TCR was rearranged in one patient. The TCR of the leukemic cells of a patient MH with CD3+, CD4 and CD8 (double positive marker: DP) recognised rabbit IgG presented by macrophages. The recognition was class II restricted. We examined the expression pattern of CD8 subunits and found that DP leukemic cells commonly expressed CD8 alpha+ beta-. These results suggested that DP leukemic cells were CD4+ T cells and expressed CD8 alpha secondarily. The p75 IL-2 receptors were detected, however, the modulation of p56lck in the process of IL-2 signal transduction were not found out. There was no association between p75 and p56lck when leukemic LGL cells proliferated on stimulation with IL-2.