Please cite this article in press as: Popovic-Kuzmanovic, D., et al., Increased activity of interleukin-23/interleukin-17 cytokine axis in primary antiphospholipid syndrome. Immunobiology (2012), http://dx.doi.org/10.1016/j.imbio.2012.03.002 ARTICLE IN PRESS G Model IMBIO-50867; No. of Pages 6 Immunobiology xxx (2012) xxx–xxx Contents lists available at SciVerse ScienceDirect Immunobiology j ourna l homepage: www.elsevier.de/imbio Increased activity of interleukin-23/interleukin-17 cytokine axis in primary antiphospholipid syndrome Dragana Popovic-Kuzmanovic a , Ivana Novakovic b , Ljudmila Stojanovich a , Ivona Aksentijevich c , Nevena Zogovic d , Gordana Tovilovic d , Vladimir Trajkovic e,∗ a Medical Center “Bezanijska Kosa”, University of Belgrade, Belgrade, Serbia b Institute of Biology, School of Medicine, University of Belgrade, Belgrade, Serbia c Genetics and Genomics Branch, National Institute of Arthritis, Musculoskeletal, and Skin Diseases, NIH, Bethesda, MD, USA d Institute of Biological Research, University of Belgrade, Belgrade, Serbia e Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia a r t i c l e i n f o Article history: Received 24 February 2012 Accepted 20 March 2012 Keywords: Antiphospholipid syndrome IL-17 IL-23 TGF- Gene polymorphism a b s t r a c t The aim of the study was to investigate serum concentrations of interleukin (IL)-17 and IL-17-inducing cytokines IL-23 and transforming growth factor (TGF)-, as well as IL-17 single nucleotide polymorphism (SNP) rs2275913 in patients with primary antiphospholipid syndrome (PAPS). We studied fifty patients with PAPS and fifty age- and sex-matched healthy controls. The cytokine levels were measured by ELISA, while the rs2275913 SNP located in promoter region of IL-17 gene was genotyped using real-time PCR. The significantly higher levels of IL-17 (p = 0.002), IL-23 (p < 0.001) and TGF- (p = 0.042) were found in PAPS patients (median 13.1, 9.4, and 125.6 pg/ml, respectively) compared to the control group (6.8, 4.9 and 44.4 pg/ml). There was a significant positive correlation between concentrations of IL-17 and IL-23 (r = 0.540, p < 0.001), but not between those of IL-17 and TGF-. No statistically significant differences were observed in the distribution of genotypes and alleles of the IL-17 rs2275913 variants in patients with PAPS compared to healthy subjects. The blood concentrations of IL-17 did not differ in subjects with different rs2275913 genotypes or patients with or without antiphospholipid antibodies. Finally, a trend toward higher IL-17 levels (p = 0.063) and the significantly higher IL-17 concentrations (p = 0.012) were observed in PAPS patients with deep vein thrombosis and thrombocytopenia, respectively. These data demonstrate that IL-23/IL-17 axis, stimulated independently of TGF- increase IL-17A gene polymor- phism and antiphospholipid antibody production, might contribute to vascular manifestations of PAPS. © 2012 Elsevier GmbH. All rights reserved. Introduction Antiphospholipid syndrome (APS) is a systemic autoimmune disease in which the excessive blood clotting and/or certain complications of pregnancy (fetal loss or premature birth) are associated with the presence of antibodies that recognize anionic phospholipid–protein complexes (Ruiz-Irastorza et al. 2010). Although antiphospholipid antibodies such as those against cardi- olipin, 2 glycoprotein 1 or lupus anticoagulant are both diagnostic markers for, and pathogenic drivers of APS (Sherer et al. 2007), the exact pathophysiological mechanisms of this disorder have Abbreviations: 2GPI, 2 glycoprotein-I; CL, cardiolipin; LA, lupus anti- coagulant; PAPS, primary antiphospholipid syndrome; SNP, single nucleotide polymorphism. ∗ Corresponding author. Tel.: +381 11 3643 233; fax: +381 11 3643 235. E-mail address: vtrajkovic@med.bg.ac.rs (V. Trajkovic). not been established. The primary antiphospholipid syndrome (PAPS) occurs in the absence of any other related disease, while in secondary APS the presence of antiphospholipid antibodies is associated with the systemic lupus erythematosus (Shoenfeld et al. 2009). The patients with APS may also have cardiac, neu- rological, renal, cutaneous or hematologic symptoms, the latter including mild to moderate thrombocytopenia (Gigante et al. 2009; Rodrigues et al. 2010; Soltesz et al. 2007; Uthman et al. 2008; Weinstein and Piette 2008). Interleukin (IL)-17A (referred to hereafter as IL-17) is the pro- totype member of the IL-17 cytokine family, comprising of several structurally similar proteins involved in the immune response, as well as in the homeostasis of tissues in health and disease beyond the immune system (Gaffen 2011; Moseley et al. 2003). IL-17- producing T helper (Th)17 cells have recently been identified as a unique subset of helper T cells responsible for induction and prop- agation of autoimmune responses in animal models and possibly in humans (Fouser et al. 2008). The lineage commitment and/or 0171-2985/$ – see front matter © 2012 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.imbio.2012.03.002