T-plastin (PLS3) gene expression differentiates Sézary syndrome from mycosis fungoides and inflammatory skin diseases and can serve as a biomarker to monitor disease progression.

BACKGROUND

Cutaneous T-cell lymphoma (CTCL) is a group of lymphoproliferative disorders that includes mycosis fungoides (MF) and Sezary syndrome (SS). T-Plastin (PLS3) is an actin-bundling protein that has been found to be highly expressed in Sezary cells but not in normal PBMCs. Here, we describe the value of using PLS3 as a sensitive molecular marker for differentiating stages of MF from SS, and for monitoring development of SS from MF.

OBJECTIVES

To determine the relationship between PLS3 expression level and SS, and disease progression and response to treatment in patients with MF/SS.

METHODS

Total RNA from PBMCs from normal volunteers, MF/SS, and psoriasis patients were measured by quantitative PCR for PLS3 gene expression.

RESULTS

In PBMCs from MF/SS and psoriasis patients, PLS3 expression was increased markedly in SS (greater than 400-fold) compared to that seen in early and late stage MF patients without SS cells or in patients with psoriasis. In a patient whose disease progressed to SS from MF, the PLS3 level in PBMCs showed an increased with disease progression. With treatment, the level of PLS3 decreased with chemotherapy and bone marrow transplantation.

CONCLUSIONS

PLS3 expression is a valuable and sensitive molecular biomarker to differentiate MF from SS. The measure of this gene may have value in conjunction with gene rearrangement studies to monitor disease severity or progression from MF to SS. Furthermore, PLS3 is not expressed in other inflammatory skin diseases, and may be valuable to distinguish SS from other cutaneous diseases associated with generalized erythroderma.