The use of anti-T-cell receptor-Vβ antibodies for the estimation of treatment success and phenotypic characterization of clonal T-cell populations in cutaneous T-cell lymphomas

Summary. Sezary syndrome and Mycosis fungoides are the most common forms of cutaneous T-cell lymphomas. To assess the response to different therapies especially in Sezary syndrome, it is helpful to monitor the percentage of circulating tumour cells in the blood. The use of T-cell receptor (TCR)-Vβ specific monoclonal antibodies provides a suitable tool for detecting Sezary cells. In this study, we analysed the levels of clonal CD4+Vβ+ cells of seven patients with various treatment modalities using flow cytometry and investigated the immunophenotype of the clonal cells by double staining with a panel of antibodies recognizing lymphatic surface markers. Additionally, a polymerase chain reaction-denaturing gradient gel electrophoresis assay was performed on clonal CD4+Vβ2+ cells, showing that these cells carry a Vγ10/11, JγP1/2 TCR rearrangement. Follow-up studies revealed close association of the Vβ+ clone developmentwith the clinical response to different therapiesinsixpatients. Intwo cases, the CD4+Vβ+ cells decreased accompanied by partial regression or even complete remission. In four cases, a stable or increasing clonal CD4+Vβ+ population reflected well a stable or progressing course of the disease. Double staining of Vβ+ cells revealed the following pattern, CD3+, CD5+, CD7+, CD28+, CD80–, CD86+ and human leucocyte antigen (HLA) class I+. In contrast, HLA-DR was heterogeneously expressed. We conclude that identification and monitoring of CD4+Vβ+ clonal T cells by fluorescence-activated cell sorting with double staining is a suitable method to assess clinical responses to different therapies.