Perfil de células T CD4+CD25+FoxP3+ e células B CD3-CD19+ em pacientes com síndrome antifosfolipídica primária e secundária

Abstract

Introduction: Antiphospholipid syndrome (APS) is characterized by venous or arterial thromboses, fetal losses and thrombocytopenia, in the presence of antiphospholipid antibodies (aPL). CD4+CD25+Foxp3+ regulatory T (Treg) cell dysfunction has been documented in various autoimmune disorders, but not in antiphospholipid syndrome (APS) up to date. Methods: In this cross-sectional study, we aim to investigate CD4+CD25+Foxp3+ Treg cells and CD3 CD19+ B cells in patients with primary APS, APS secondary to systemic lupus erythematosus (SLE) and healthy controls. Cell subtypes were immunophenotyped using specific monoclonal antibodies (anti-CD3 CY5, anti-CD4 FITC, anti-CD25, anti-Foxp3, anti-CD19 PE) and flow cytometry. Results: Twenty and five patients with primary APS, 25 with APS secondary to SLE and 25 age- and sexmatched controls were studied. The percentage Treg cells and CD3 CD19+ B cells were found significantly lower in primary APS and APS secondary to SLE patients as compared to controls (all p < 0.05). Decreasing levels of circulating Treg cells correlated to higher scores of lupus activity (r=-0.75, p<0.0001). Number of circulating Treg cells did not significantly vary among users or nonusers of chloroquine, azathioprine and corticosteroids (p=0.90, p=0.76 and p=0.29, respectively). Conclusion: A dysfunction in CD4+CD25+Foxp3+ Treg cells may represent one of the mechanisms leading to autoimmunity in APS patients. The decreased number of CD3 CD19+ B cells of APS patients warrants further elucidation.