Mogamulizumab induces long term immune restoration and reshapes tumor heterogeneity in Sézary syndrome

Mogamulizumab, an anti‐CCR4 monoclonal antibody, has been shown to increase progression‐free survival in cutaneous T‐cell lymphoma. We hypothesized that besides the targeted depletion of Sézary cells (SCs), mogamulizumab may reshape the immune tumor microenvironment. Both malignant and benign compartments from 26 Sézary patients with B2 stage before mogamulizumab initiation were prospectively analyzed using KIR3DL2 and TCR‐Vβ markers, serological markers and molecular assessments of clonality. Prior to mogamulizumab, the benign subset of CD4+ T‐cells displayed exhausted phenotypes, with an increased gradient in D1/TIGIT/DNAM/CD27/CD28 and CD70 expression from age‐ matched controls to patient benign CD4+T cells and to SCs...