AB0544 Role of anti-neuronal antibodies (A-NA) in epilepsy lupus patients

Background Epilepsy may occur before, during or after SLE diagnosis, with a prevalence of 6.7%–14%. Recent works showed that a significant proportion of patients with not responding to antiepileptic drugs (AED)-resistant epilepsy harbour neural-specific autoantibodies. The detection of these antibodies may predict a favourable response to immunotherapy (75% of patients).1 A small number of recent studies have described the existence of antibodies directed against a-NA in neuropsychiatrics SLE (NPSLE), and data are contrasting.2 Objectives Evaluate the clinical features of epilepsy in patients with SLE. Evaluate any clinical-instrumental differences in epilepsy in patients diagnosed with epilepsy prior to many years of SLE. Evaluate antibodies associated with neurological phenotypes. Methods We retrospectively evaluated a SLE cohort for epileptic seizures. We single out 11 epileptic SLE patients (about 10%). A control group of 10 SLE patients with no NPSLE was matched for sex and age. Sera patients were tested for: ANA, a-ds-DNA, a-ENA, LAC, anticardiolipin IgG and IgM, anti-β2-glycoprotein IgG and IgM, a-nucleosomes, a-ribosomal. All sera were evaluated for the presence of autoantibodies directed to neural antigens by indirect immunofluorescence on frozen sections of mouse brain, cell-based assays (a-NA, a-NMDA). Results In our cohort of SLE patients with epilepsy we confirm the association between SLE and epilepsy of the mesial temporal lobe (MTLE). Six patients had epilepsy at least 5 years prior to SLE diagnosis (average 11.6 years)., the presence of minor symptoms suggestive of SLE (eg arthralgia, rash.) was reported many years before immunological diagnosis. Moreover seizure frequency was achieved when they started immunosuppressive drugs. Anti-NA antibodies were present in 6/11 (54%) of patients with SLE/epilepsy compared with 2/10 (20%) of the control group (p=0.05). We obtained specificity 0.80 (95% CI 0.44–0.97), and sensitivity 0.54 (95% CI 0.23–0.82). Among the other antibodies studied, we have not found any statistically significant difference between the two groups. Conclusions Anti-NA antibodies could be a useful biomarker of NPSLE, allowing a more precocious diagnosis and therefore a more early therapeutic intervention with improvement of long-term prognosis and quality of life. References [1] Iorio R, et al. 2015Eur J Neurol [2] Kampylafka EI, et al. 2016Lupus Disclosure of Interest None declared