Single TCR-Vβ2 evaluation discloses the circulating T cell clone in Sezary syndrome: one family fits all!

Sézary Syndrome (SS/L-CTCL) is a rare but aggressive variant of cutaneous T cell lymphoma (CTCL), characterized by erythroderma, lymphadenopathy, and the presence of a circulating memory CD4(+) T cell malignant clone with a skin homing behavior, lacking CD26 and CD49d and over-expressing CD60. The availability of a panel of monoclonal antibodies recognizing distinct TCR-Vβ families, allows to typify the clone by flow cytometry in about 70 % of cases. The TCR-Vβ repertoire of 533 individuals, comprising 308 patients affected by CTCL, 50 healthy donors, and subjects affected by various non-neoplastic dermatological affections was evaluated by flow cytometry. Statistical analyses were performed using the SPSS statistical software package for Microsoft Windows (SPSS, version 21, Chicago, IL). TCR-Vβ2 levels below 5.4 % or above 39.5 %, within total CD4(+) T cells, showed the best balance between sensitivity (98.1 %) and specificity (96 %) to identify the presence of a clone in the peripheral blood of patients affected by SS. Based on this observation, a "two-step" procedure in the detection of the malignant T cell clone in CTCLs is herein suggested. TCR-Vβ2 assessment in all cases (first step). In the case of TCR-Vβ2 levels above 39.5 %, the presence of a clonal expansion of this family is suggested, deserving further confirmation by means of T cell gene rearrangement evaluation. In patients having a TCR-Vβ2 reactivity below 5.4 % (second step), the entire TCR-Vβ repertoire should be evaluated to typify the expanded clone. In conclusion, the single TCR-Vβ2 expression check, instead of the entire repertoire assessment, represents an easy and cost-effective method for the recognition of CTCL aggressive leukemic variant.