A CD8⁺CD28^null phenotype and increased NKR expression characterizes T-LGLL cells. (A) CD8⁺ T cells isolated from LGLL patients and healthy donors were analyzed by 2-color flow cytometry for the cell surface expression of CD28. (B) Dot plots of CD8⁺/CD28⁺ expression are shown for 1 control and 1 LGLL patient. (C) The presence of activating NKRs on CD8⁺ cells were analyzed using flow cytometry. Results from 1 LGLL patient and 1 control are shown. Results from 10 patients are summarized in Table 1.