CD5 and T-cell large granular lymphocyte leukemia: In most cases, T-LGLL is characterized by an immunophenotype of cytotoxic T-lymphocytes (CD3+/CD8+) that co-express the natural killer (NK)-cell lineage-associated antigens CD16 and/or CD57, and diminished or absent expression of the pan-T-cell markers CD5 and/or CD7 [6, 7].