CASE REPORT: BICLONAL SÈZARY SYNDROME

Sézary Syndrome (SS) is defined by the triad of erythroderma, generalized lymphadenopathy, and the presence of clonal T cells with cerebriform nuclei (Sézary cells) in peripheral blood. In addition, one or more of the following criteria are required: an absolute Sézary cell count ≥ 1000/μL, an expanded CD4+ T-cell population resulting in a CD4:CD8 ratio of ≥ 10, and loss of one or more T cell antigens. T cells have a CD3+, CD4+, CD8(-) phenotype, and characteristically lack CD7 and CD26. The normal counterparts of Sézary cells are circulating central memory T cells (CD27+, CD45RA(-), CD45RO+). According to the degree of circulating involvement, Staging B (“blood”) for Sézary syndrome follow these criteria: B0: circulating Sezary cells (Fig. 2A) below 250 cells/mm3 or < 5% atypical lymphoid cells in the smear; B1: circulating Sezary cells < 1000 cells/mm3 or 5-20% atypical cells in the smear; B2: circulating Sezary cells above 1000 cells/mm3 or > 20% atypical lymphoid cells in the smear. Male patient, 88 years old, previous diagnosis of Mycosis fungoides, Peripheral blood sample with white blood count 18,000 cells, 25%TCD4+ and 9.3% Double-Positive Alfa/Beta populations with dim expression of TCD3. Flow Cytometry: 41.5% T Cells: *25% TCD4+ CD3dim CD7+/++ CD27+ CD45RA(-) TCRCBeta1(-)100% (monoclonal); *9.3% Double-negative TCRAlfa/Beta+ CD3dim CD7+ CD27+ CD45RA(-); TCRCBeta1(-)100% (monoclonal); *3% TCD4+ TCRCBeta1+ 36.5% (polyclonal); *3.9% TCD8+ TCRCBeta1+28% (polyclonal). Negative expression: CD8 CD30 CD38 CD45RA CD56 CD57 CD94 TCL1 TCRCBETA1 TCR GAMMA/DELTA. The normal counterparts of Sézary cells are circulating central memory T cells (CD27+, CD45RA(-), CD45RO+); the phenotype profile in our case, with 2 identifiable clones (one TCD4+ clone and one Double-Negative Alfa/Beta clone), matches this description.