CME ArticleA Long-Term Study of Persistent Sézary Syndrome: Evidence for Antigen Shift by Multiparameter Flow Cytometry and Its Significance in Overall SurvivalHoffmann, Jenny C. MD*; Atwater, Susan K. MD†; Hong, Eric‡; Kumar, Jyoti MD, MS§; Khodadoust, Michael MD, PhD¶; Kim, Youn MD, PhD║; Ohgami, Robert S. MD, PhD**Author Information *Fellow, Department of Pathology, Stanford University, Stanford CA; †Associate Professor, Department of Pathology, Stanford University, Stanford CA; ‡Academic Program Manager, Department of Dermatology, Stanford University, Stanford CA; §Resident, Department of Pathology, Stanford University, Stanford CA; ¶Assistant Professor, Department of Medicine and Department of Dermatology, Stanford University, Stanford CA; ║Professor, Department of Dermatology and Department of Medicine, Stanford University, Stanford CA; and **Associate Professor, Department of Pathology, University of California San Francisco, San Francisco CA. Correspondence: Robert S. Ohgami, MD, PhD, Associate Professor, Department of Pathology, University of California, San Francisco, 513 Parnassus Avenue, Room HSW450, San Francisco, CA 94143 (e-mail: firstname.lastname@example.org). All authors, faculty, and staff in a position to control the content of this CME activity and their spouses/life partners (if any) have disclosed that they have no relationships with, or financial interests in, any commercial organizations relevant to this educational activity. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.amjdermatopathology.com). The American Journal of Dermatopathology: June 2020 - Volume 42 - Issue 6 - p 389-396 doi: 10.1097/DAD.0000000000001637 Buy SDC Take the CME Test Metrics Abstract Sézary syndrome (SS) is a peripheral T-cell lymphoma characterized by erythroderma, diffuse lymphadenopathy, and circulating neoplastic T cells, which classically show a helper T-cell immunophenotype with loss of CD7 and CD26. Flow cytometry is often used to identify and enumerate populations of Sézary cells in the peripheral blood; however, the significance and frequency of antigen shift over time is unclear. In this article, we follow the immunophenotype of the neoplastic T-cell population from 28 patients with SS across 415 flow cytometry studies. Antigen shift for each patient was assigned as none, minimal = 1–2 markers by 1°, moderate = up to 3 markers, or marked ≥ 4 markers. Sixty-four percent (18/28) of patients showed antigen shift, and among those with antigen shift, the majority showed minimal (8/18) or moderate antigen shift (7/18) with fewer demonstrating marked shift (3/18). Patients without antigen shift showed a trend toward improved overall survival in comparison with patients demonstrating any degree of antigen shift. Antigen shift is seen in a significant proportion of cases of SS with long-term follow-up and may be a marker of more aggressive disease. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.