Sézary Syndrome. (A) Peripheral blood smear demonstrating an abnormal lymphoid cell with an irregular folded nucleus. Wright Giemsa stain, magnification ×100. Images were acquired as in Figure 1. (B) Representative flow cytometric dot plots with population of interest highlighted in green: CD3 versus CD7, demonstrating many CD7⁻ CD3⁺ T cells; CD3 versus CD16 and/or CD57, demonstrating lack of NK-associated antigen expression; CD26 versus CD4, demonstrating many CD4⁺ cells, including more than 30% CD26⁻ cells; and CD3 versus CD25, demonstrating only partial weak intensity staining of T cells for CD25.