THU0504 Regulatory T Cells in Peripheral Blood of Patients with Antiphospholipid Syndrome
Authors: N. Soroka, T. Talako, V. Smolnikova
Journal: Annals of the Rheumatic Diseases (2014)

<h3>Background</h3> 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 [1]. Role of cellular immunity is still under investigation [2]. 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 [3]. <h3>Objectives</h3> To determine the level of Treg and find correlation with APL antibodies and clinical features in patients with APS. <h3>Methods</h3> 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. <h3>Results</h3> 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)*10<sup>9</sup>/L and 0,4348 (0,3539-0,8200)*10<sup>9</sup>/L in APS patients and 0,7992 (0,6124-0,8784)*10<sup>9</sup>/L and 0,4276 (0,3240-0,5451)*10<sup>9</sup>/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)*10<sup>9</sup>/L, in APS patients - 0,0065 (0,0042-0,0088)*10<sup>9</sup>/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*10<sup>9</sup>/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*10<sup>9</sup>/L) did not show symptoms of vasculopathy. <h3>Conclusions</h3> 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. <h3>References</h3> Shoenfeld Y, Krause I, Kvapil F et al. Prevalence and clinical correlations of antibodies against six beta2-glycoprotein-I-related peptides in the antiphospholipid syndrome. Journal of Clinical Immunology 2003;23(5):377-383. Karakantza M, Theodorou GL, Meimaris N et al. Type 1 and type 2 cytokine-producing CD4+ and CD8+ T cells in primary antiphospholipid syndrome. Annals of Hematology 2004;83:(11):704-711. Dal Ben ER, do Prado CH, Baptista TS et al. Decreased levels of circulating CD4+25+Foxp3+ regulatory cells in patients with primary antiphospholipid syndrome. Journal of Clinical Immunology 2013;33(4):876-879. <h3>Disclosure of Interest</h3> : None declared <h3>DOI</h3> 10.1136/annrheumdis-2014-eular.4485