Background Antiphospholipid syndrome (APS) is characterized by thrombosis, fetal loss and presence of antiphospholipid (APL) antibodies, the most studied of which are anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) IgG and IgM antibodies . Role of cellular immunity is still under investigation . Regulatory T cell (Treg) dysfunction has been demonstrated in some autoimmune disorders (rheumatoid arthritis, multiple sclerosis, diabetes). There are only several publications about role of Treg in APS .
Objectives To determine the level of Treg and find correlation with APL antibodies and clinical features in patients with APS.
Methods 23 APS patients (diagnosed according Sidney criteria, 2004) mean age 31,1±5,4 years out of pregnancy were examined. In control group 12 healthy donors mean age 34,3±5,2 years without history of spontaneous abortions or thrombosis were included. IgG and IgM aCL and ab2GPI antibodies were measured by ELISA. In peripheral blood Treg (CD4+CD25+CD127-), CD3+CD4+ and CD3+CD8+ cells were detected by flow cytometry.
Results In APS patients average level of aCL IgG was 4,19 (2,28-63,95) GPL, aCL IgM – 11,95 (2,12-47,9) MPL, aβ2GPI IgG – 6,24 (6,24-11,3) U/ml, aβ2GPI IgM – 20,24 (6,45-60,67) U/ml. Healthy donors were APL-negative. Absolute number of CD3+CD4+ and CD3+CD8+ cells was 0,6753 (0,4413-0,8185)*109/L and 0,4348 (0,3539-0,8200)*109/L in APS patients and 0,7992 (0,6124-0,8784)*109/L and 0,4276 (0,3240-0,5451)*109/L in control group respectively. In peripheral blood of healthy donors absolute number of Treg was detected at average level 0,0138 (0,011-0,0152)*109/L, in APS patients - 0,0065 (0,0042-0,0088)*109/L (p=0,031) and showed correlation with aβ2GPI IgM antibodies level (R=0,60; p=0,015) and absolute number of CD3+CD8+ cells (R=0,54; p=0,03). Patients with APS with Treg level lower than 0,0057*109/L (n=13) have vasculopathy (vascular purpura) and mild form of thrombocytopenia among clinical symptoms of APS. Patients with higher level of Treg (more than 0,0057*109/L) did not show symptoms of vasculopathy.
Conclusions We found that absolute number of regulatory T cells is markedly decreased in peripheral blood of patients with APS in compare to healthy donors; it has correlation with anti-β2-glycoprotein I IgM. Vasculopathy is observed more often in APS patients with lower level of Treg.
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Disclosure of Interest : None declared