THU0706 Presence of extractable nuclear antigens (ENA) antibodies in a large population-based cohort from the netherlands

Abstract

Background: Previous studies have demonstrated that years before the clinical onset of auto-immune diseases, auto-antibodies can already be present in the blood of these patients. However, it is also known that some individuals can have these auto-antibodies and will never develop an auto-immune disease. So far, little information is available on the presence of Extractable Nuclear Antigens antibodies (anti-ENA) in the general population in relation to the risk of developing an auto-immune disease. Objectives: To estimate the prevalence of anti-ENA and their association with the presence of known risk factors of Systemic Lupus Erythematosus (SLE) and Sjögren Syndrome (SS) in the general Dutch population. Methods: Lifelines is a prospective population-based cohort study in the Netherlands. Cross-sectional data from 40 135 participants were analysed. The detection of anti-ENA was performed using the ENA-CTD (connective tissue disease) screen on the Phadia-250 analyser with a ratio >1.0 are considered positive. An extensive questionnaire was taken on demographic and clinical information (e.g. early musculoskeletal symptoms). Furthermore, some general blood parameters were available. SLE and SS were defined by a combination of self-reported SLE or SS, specific medication use and visiting a medical specialist within the last year. Characteristics were compared between 3 groups: SLE/SS patients, anti- ENA positive, and anti-ENA negative participants (without defined SLE/SS). Results: Of the total 40 135 consecutive individuals, 41 were detected as having defined SLE or SS of whom 48% were anti-ENA positive SLE/SS patients were older and more often female. Of the remaining individuals,40,094 1089 (2.7%) were anti-ENA positive and anti-ENA positivity was also significantly associated with older age and female gender in this population. No significant associations were found for smoking and alcohol intake. As might be expected, SLE/SS patients reported more often complaints concerning fatigue, joint pain and joint stiffness. But also anti-ENA-positive participants reported significantly more often joint stiffness compared to anti-ENA-negative participants. Interestingly, levels of haemoglobin, leucocytes and lymphocytes were significantly decreased in anti-ENApositive participants compared to anti-ENA-negative participants. Conclusions: In this large population-based study, the prevalence of anti-ENApositivity was 2.8% for the total group and 2.7% when excluding patients with SLE or SS. Older age, female gender, joint complaints and lower levels of haemoglobin, leucocytes and lymphocytes were more frequently present in anti-ENA-positive participants. Longitudinal studies are performed up to 15 years to investigate which individuals might develop SLE or SS to be able to develop prediction models.