title: Patients with systemic lupus erythematosus and secondary antiphospholipid syndrome have decreased numbers of circulating CD4⁺CD25⁺Foxp3⁺ Treg and CD3⁻CD19⁺ B cells.
abstract: BACKGROUND
  CD4+CD25+Foxp3+ regulatory T (Treg) cell depletion has been reported in systemic lupus erythematosus (SLE) and, recently, in primary antiphospholipid syndrome (APS); the issue has not been studied in SLE patients with secondary APS (SLE/APS) so far.
  
  
  OBJECTIVE
  To quantify total lymphocytes, Treg cells, CD3+CD19- T cells and CD3-CD19+ B cells in SLE/APS patients and healthy controls.
  
  
  METHODS
  Cell subtypes underwent immunophenotyping using specific monoclonal antibodies (anti-CD3 CY5, anti-CD4 FITC, anti-CD25, anti-Foxp3, anti-CD19 PE) and flow cytometry.
  
  
  RESULTS
  Twenty-five patients with SLE/APS (mean age 43.5 years, 96% females, 96% caucasians, mean duration of disease 9.87 years, mean SLEDAI 10 ± 5.77) and 25 age and sex-matched controls entered the study. It was realized that the numbers of Treg and CD3- CD19+ B cells were significantly lower in SLE/APS patients than in controls (all p < 0.05).Treg and CD3-CD19+ B cells remained numerically low after controlling (ANCOVA) for percentage of total lymphocytes (p < 0.05). Decreasing levels of circulating Treg and CD3-CD19+ B cells correlated to higher scores of lupus activity (rs = -0.75, p < 0.0001; rs = -0.46, p = 0.021, respectively). Number of Treg cells and CD3-CD19+ B lymphocytes did not significantly differ in users or nonusers of chloroquine, azathioprine and corticosteroids (all p > 0.05).
  
  
  CONCLUSIONS
  In this preliminary study, patients with SLE and secondary APS showed depletion of Treg and CD3-CD19+ B cells; decreasing numbers of both subtypes correlated to a higher SLEDAI. Treg cells depletion might contribute to the autoimmune lesion seen in patients with SLE/APS. The reduced number of CD3-CD19+ B cells seen in these patients deserves more studies in order to get further elucidation.
authors: Laboratório de Imunosenescência, Instituto de Pesquisa Biomédica, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors: Ester Rosári Raphaelli
authors: ER
authors: Dal Ben
authors: Laboratório de Imunosenescência, Instituto de Pesquisa Biomédica, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors: Carine Hartmann
authors: CH
authors: do Prado
authors: Laboratório de Imunosenescência, Instituto de Pesquisa Biomédica, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors: Talita Siara Almeida
authors: TS
authors: Baptista
authors: Laboratório de Imunosenescência, Instituto de Pesquisa Biomédica, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors: Moisés Evandro
authors: ME
authors: Bauer
authors: Departamento de Reumatologia, Hospital São Lucas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors: Henrique Luiz
authors: HL
authors: Staub
mesh_terms: D000328:Adult; D016736:Antiphospholipid Syndrome / Q000097:blood*; D001402:B-Lymphocytes; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D050378:T-Lymphocytes, Regulatory