Decreased levels of circulating CD4+CD25+Foxp3+ regulatory T cells in patients with primary antiphospholipid syndrome.
BACKGROUND
CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cell dysfunction has been documented in various autoimmune disorders, but not in antiphospholipid syndrome (APS) so far.


METHODS
In this cross-sectional study, we aim to investigate CD4(+)CD25(+)Foxp3(+) Treg cells, CD3(+)CD19(-) T cells and CD3(-)CD19(+) B cells in patients with primary APS 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 patients with APS and 20 age- and sex-matched controls were studied. The percentage of total lymphocytes, activated Th cells (CD4+CD25+), Treg cells and CD3(-)CD19(+) B cells were found significantly lower in APS patients as compared to controls (all p < 0.05).


CONCLUSIONS
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.
Laboratory of Immunosenescence, Institute of Biomedical Research, Faculty of Biosciences, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Brazil.
Ester Rosári Raphaelli
ER
Dal Ben
Carine Hartmann
CH
do Prado
Talita Siara Almeida
TS
Baptista
Moisés Evandro
ME
Bauer
Henrique Luiz
HL
Staub
D000328:Adult; D018941:Antigens, CD19 / Q000378:metabolism; D016736:Antiphospholipid Syndrome / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D001775:Blood Circulation; D015704:CD4 Antigens / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D018941:Antigens, CD19; D015704:CD4 Antigens; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053645:Interleukin-2 Receptor alpha Subunit