Heterogeneity of Circulating CD4+ Memory T-Cell Subsets in Erythrodermic Patients: CD27 Analysis Can Help to Distinguish Cutaneous T-Cell Lymphomas from Inflammatory Erythroderma

BACKGROUND: Chronic dermatoses, as well as Sézary syndrome (SS), the erythrodermic and leukaemic cutaneous T-cell lymphoma, display a T-cell memory pattern. Recent findings suggest that different memory T-cell subsets can be recognized based on CD27 and CD45RO/RA expression. No data are reported as to CD27 expression in SS. OBJECTIVES: To evaluate different memory T-cell subsets, i.e. central memory (TCM), effector memory (TEM) and terminally differentiated cells in SS and inflammatory erythroderma (IE). MATERIALS AND METHODS: Forty SS and 137 IE patients were included. CD27 and CD45RO/CD45RA expression was analysed by flow cytometry on peripheral blood lymphocytes and immunohistochemistry. RESULTS: A significantly higher expression of the CD4+CD27+CD45RA- TCM subset was observed in SS whilst IE patients were characterized by increased CD4+CD27-CD45RA- TEM levels. The Vbeta-restricted population was homogeneously CD4+CD26-CD27+ in the SS subjects. CONCLUSIONS: SS and IE are characterized by a different memory T-cell subset expression; CD27 expression could be used as an additional diagnostic tool in the differential diagnosis.