The B-Cell Chemoattractant Factor Cxcl13 Is Expressed In The Malignant Lymphocyte Of The Sezary Syndrome.

Sézary Syndrome (SS) is a rare and aggressive form of Cutaneous T-Cell Lymphoma (CTCL) characterised by a distinct metastatic pattern mainly involving blood and skin. Our expression analyses performed by microarrays demonstrated that many chemokines resulted up-regulated in this type of lymphoma. Since these chemoattractant molecules play a critical role in cellular recruitment and homing to tissues and in the metastatic process of several tumors, we focused our attention on one of them named CXCL13, a lymphoid chemokine involved in B-cell compartmental homing within secondary lymphoid organs. Peripheral Blood Mononuclear cells (PBMCs) were isolated from blood obtained from SS patients and controls by Ficoll-Hypaque density gradient centrifugation (Sigma Aldrich). SS cells and healthy resting CD4+ lymphocytes were purified by positive selection using an anti-human-CD4 conjugated dynabeads (Oxoid). Total RNA was extracted using the Trizol reagent (Life Technologies). Quantitative-Real Time RT-PCR analysis was performed on CD4+ sorted from 14 SS patients and 3 controls. CXCL13 primers were designed by means of the Primer Express software package (Applied Biosystems). The qRT-PCR were performed with a SYBR Green I dye chemistry and AmpliTaq Gold DNA Polymerase on an ABI PRISM 7000 machine (Applied Biosystems). Immunohistochemistry analyses for CXCL13 were performed on formalin-fixed, paraffin-embedded skin biopsies from 15 SS, 15 MF, 6 MF-B cell rich patients using streptoavidin-biotin peroxidase labeling method (DAKO). Sections were counterstained with hematoxylin.