Epilepsy Research 129 (2017) 132–137 Contents lists available at www.sciencedirect.com Epilepsy Research journa l h om epa ge: www.elsevier.com/locate/epilepsyres Investigation of neuronal auto-antibodies in systemic lupus erythematosus patients with epilepsy Zerrin Karaaslan a,∗ , Esme Ekizo˘ glu a , Pınar Tektürk a , Ece Erda˘ g b , Erdem Tüzün b , Nerses Bebek a , Candan Gürses a , Betül Baykan a a Department of Neurology, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey b Department of Neuroscience, Istanbul University, Institute of Experimental Medicine, Istanbul, Turkey a r t i c l e i n f o Article history: Received 26 July 2016 Received in revised form 30 November 2016 Accepted 13 December 2016 Available online 14 December 2016 Keywords: Epilepsy Neuronal auto-antibodies Hippocampal neuropil Systemic lupus erythematosus a b s t r a c t Purpose: Epilepsy is an important feature for neuropsychiatric involvement in systemic lupus erythemato- sus (SLE) with unknown mechanism. Our aim was to investigate the presence of neuronal auto-antibodies (NAbs) in neuropsychiatric SLE (NPSLE). Methods: Eighteen SLE patients (17 females, 1 male) experiencing recurrent seizures were enrolled to this study. Their clinical characteristics, EEG and MRI findings and follow-up information were eval- uated from their files. Antibodies against voltage-gated potassium channel (VGKC)-complex antigens, contactin-associated protein-like 2 (CASPR-2), leucine-rich, glioma inactivated 1 (LGI1), glutamic acid decarboxylase (GAD), N-methyl-d-aspartate receptor (NMDA-R), alpha-amino-3-hydroxy-5-methyl-4- isoxazoleproprionic acid receptor (AMPA-R) and type B gamma aminobutyric acid receptors (GABA B -R) were screened in the sera of these patients. Moreover, indirect immunohistochemistry and immunocy- tochemistry tests were performed to reveal neuropil antibodies. Results: Six out of 18 patients (33.3%) had various forms of NAbs. Among them, one patient had antibodies against GAD, one patient with hippocampal sclerosis on MRI was CASPR-2 antibody positive, whereas the remaining four patients showed hippocampal neuropil staining. We could not find a significant differ- ence between seropositive and seronegative groups, regarding the clinical characteristics, EEG and MRI findings. Conclusion: This study is the first to show hippocampal neuronal staining (4/18) reflecting antibodies against unknown neuronal cell surface antigens in SLE patients with epilepsy, besides the rare occurrence of GAD and CASPR2 antibodies. Further prospective studies are needed to search for new NAbs and uncover their pathogenic role in SLE associated with epilepsy. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Systemic lupus erythematosus (SLE) is an autoimmune disease affecting multiple organ systems. Central nervous system (CNS) involvement is a major cause of morbidity and mortality in SLE patients (Hanly et al., 2010). Epileptic seizures are among the most serious neuropsychiatric manifestations of SLE and constitute one of the diagnostic criteria for neuropsychiatric SLE (NPSLE) (Liang ∗ Corresponding author at: Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Millet Cad 34093 Capa, Istanbul, Turkey. E-mail addresses: zkaraaslan@gmail.com (Z. Karaaslan), esmeekizoglu@yahoo.com (E. Ekizo˘ glu), pinartopaloglu2000@yahoo.com (P. Tektürk), eceerdag@gmail.com (E. Erda˘ g), drerdem@yahoo.com (E. Tüzün), nersesb@yahoo.com (N. Bebek), candangrss@gmail.com (C. Gürses), baykanb@istanbul.edu.tr (B. Baykan). et al., 1999). They may occur at any time in the course of the disease, possibly by diverse mechanisms. In addition to being sec- ondary to metabolic dysfunction, toxic effects of drugs lowering seizure threshold or stroke, seizures are also attributable to the primary disease activity of SLE (Andrade et al., 2008; Appenzeller et al., 2004). Autoimmunity related prothrombotic states leading to ischemic events or inflammatory mechanisms are considered to play the major role in the pathogenesis of seizures in NPSLE (Sciascia et al., 2014). A huge number of autoantibodies has been described in SLE and there is some preliminary evidence that antiphospholipid (aPL) antibodies, mainly lupus anticoagulant and high titres of anticardiolipin (aCL) IgG antibodies, are associated with epilepsy (Sherer et al., 2004). However, seizures develop only in a subset of patients having antiphospholipid syndrome (APS), whereas aPL-positivity occurs in all cases (Ganor et al., 2005). Therefore, it is not well established whether these antibodies are http://dx.doi.org/10.1016/j.eplepsyres.2016.12.006 0920-1211/© 2016 Elsevier B.V. All rights reserved.