Importance of Flow Cytometry in the Diagnosis of Sezary Syndrome in the State of Rio Grande Do Norte, Brazil

Introduction:Sézary Syndrome (SS) is a leukemic form of Fungal Mycosis (FM), a rare form of T-cell lymphoma, characterized by erythroderma, generalized lymphadenopathy and infiltration of neoplastic T cells (Sézary cells) with cerebriform nucleus on the skin, lymph nodes and peripheral blood, being observed predominantly in men and individuals over the age of 60 and black. In the diagnosis of SS / FM, at least one of the criteria must be observed: minimum absolute Sézary cells count of 1000/mm3, expansion of TCD4+ cells with a ratio CD4/CD8 >10, loss of at least one mature T cell antigens as CD2, CD3, CD5, CD7 and CD26 in associated with increased lymphocyte count with evidence of a clone of circulating TCD4 cells determined by flow cytometry (CF).Objective:To investigate MF/SS in patients diagnosed with cutaneous lymphoma by CF immunophenotyping. Methodology: Were investigated in samples of peripheral blood (SP) from 11 patients of both sexes with initial history of MF and confection of SS due to the presence of Sézary cells by cytomorphological analysis by CF constituted by a panel of conjugated monoclonal antibodies (AcMo) to fluorochromes and targeted to T lymphocytes: CD1a, CD2, CD3, CD5, CD7, subpopulation T-Helper (CD3+/CD4+) and T-cytotoxic (CD3+/CD8+), in addition to TCR a/b and TCR g/d; Natural Killer cells: CD16-56; B lymphocytes: CD19, CD20, CD21, CD22, CD23, IgM, IgG, IgD anti-kappa and anti-lambda, in addition to CD10, TdT, CD103, CD25, CD38 and CD138, CD45 and CD14. At the same time, a complete blood count with differential white blood cell count and investigation of clinical and demographic data such as age, sex and ethnicity/race were also performed. Results: Of the patients analyzed, 6/11 were male, the age group above 60 years and white individuals were also found in 6/11 patients. The blood count showed lymphocytosis in 9/11 patients with the presence of convoluted cells in all cases. The diagnosis of SS was confirmed by the presence of Sezary cells in PB counting above 1000/mm3, with an immunophenotype confirmed by the predominance of TCD4+ lymphocytes (CD4/CD8 ratio > 10.0), associated with the expression of CD5, CD2, TCR a/b, CD3 weakly expressed. CD7 was absent in 10/11 samples analyzed. Antigens related to B lymphocytes and NK cells were absent in neoplastic cells as well as CD10, TdT and CD1a.Conclusions:SS is a leukemic variant of FM, characterized by exfoliative erythroderma, associated with lymphadenopathy and leukemization of FM with the appearance of Sézary cells in PB. Because it is a rare and essential disease, an accurate diagnosis of these diseases is necessary, and FC is an important diagnostic confirmation tool for SS.