Sézary syndrome (SS) is a rare leukemic variant of cutaneous T-cell lymphoma (CTCL) that is characterized by erythroderma, generalized lymphadenopathy, and the presence of neoplastic CD4+ skin-homing memory T-cells (SS cells) in the skin, lymph nodes, and peripheral blood. Here, CD4 is linked to primary cutaneous T-cell non-Hodgkin lymphoma.