Case Report
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World J Immunol. Nov 27, 2013; 3(3): 68-71
Published online Nov 27, 2013. doi: 10.5411/wji.v3.i3.68
Aberrant expression of CD56 by circulating Sézary syndrome malignant T lymphocytes
Nicolas Thonnart, Caroline Ram-Wolff, Martine Bagot, Armand Bensussan, Anne Marie-Cardine
Nicolas Thonnart, Martine Bagot, Armand Bensussan, Anne Marie-Cardine, INSERM U976, Saint Louis Hospital, 75010 Paris, France
Nicolas Thonnart, Martine Bagot, Armand Bensussan, Anne Marie-Cardine, University Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France
Caroline Ram-Wolff, Martine Bagot, AP-HP, Department of Dermatology, Saint Louis Hospital, 75010 Paris, France
Author contributions: Marie-Cardine A designed the report and interpreted the data; Thonnart N performed the experiments; Ram-Wolff C and Bagot M were attending doctors for the patients; Ram-Wolff C, Bensussan A and Marie-Cardine A wrote the paper; Thonnart N and Ram-Wolff C equally contributed to this work.
Correspondence to: Dr. Anne Marie-Cardine, INSERM U976, Saint Louis Hospital, 1 avenue Claude Vellefaux, 75010 Paris, France. anne.marie-cardine@inserm.fr
Telephone: +33-1-53722050 Fax: +33-1-53722051
Received: June 27, 2013
Revised: August 28, 2013
Accepted: October 16, 2013
Published online: November 27, 2013
Processing time: 154 Days and 10.4 Hours
Abstract

Sézary syndrome (SS) is an aggressive variant of cutaneous T cell lymphoma characterized by the presence of malignant T cells in the skin, peripheral blood and lymph nodes. The tumoral population typically displays a CD3+ CD4+ CD45RO+ memory T cell phenotype. We report a case of SS with an aberrant CD56+ immunophenotype. This patient presented with a generalized erythroderma and palpable small axillary lymph nodes. SS (stage IVA) was diagnosed on histological criteria and by the detection of a major T cell clone in skin and blood, an elevated CD4/CD8 T cell ratio and Sézary cells count > 1000/mm3. Beside the Sézary cell marker KIR3DL2, immunostainings revealed that two third of the malignant cells expressed CD56 but no other natural killer (NK) cell marker such as CD16, CD160 or NKp46. This atypical expression was not linked to an activation-dependent process and remained stable during the time course of the disease. No loss of the pan T-cell markers CD2, CD3 or CD4 was detected while a complete down-modulation of CD26 was observed. Despite several lines of treatment, no durable amelioration was observed and patient died after 10 mo of follow-up. Because this CD4+ CD56+ SS case is the only one reported so far, the functional significance of CD56 expression remained difficult to assess in terms of aggressiveness and prognosis.

Keywords: Cutaneous T cell lymphomas; Sézary syndrome; CD56

Core tip: Sézary syndrome (SS) is an aggressive variant of cutaneous T cell lymphoma characterized by the presence of malignant CD4+ memory T cells in the skin, peripheral blood and lymph nodes. We here report a case of SS with an aberrant CD56+ immunophenotype. The aberrant expression of this natural killer cell marker by the tumoral cells raises the question of its relevance in terms of function and prognosis.