AB1022 UVEITIS AND ANTI-DFS70 ANTIBODIES IN JUVENIL IDIOPATHIC ARTHRITIS: AN OBSERVATIONAL RETROSPECTIVE STUDY
Authors: Giulia Melotti, Sara Pieropan, Elisa Tadiotto, Maddalena Maschio, Giulia Aiello, Federica Martinis, Federico Caldonazzi, Giorgio Piacentini, Caterina Mansoldo
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood and uveitis is one its major extra-articular manifestation. Children with JIA and a positive antinuclear antibodies (ANA) are known to be at risk to develop severe uveitis, which is usually asymptomatic and can lead to blindness if misdiagnosed. To date the finding of markers of uveitis is still a challenge. In adults anti-DFS70, ANA which have indirect immunofluorescence pattern described as dense fine spleckles (DFS pattern) and bind a 70kDa protein in immunoblot or chemioluminescence, are reported to be a marker of otherwise healthy individuals among asymptomatic ANA positive patients (in the absence of anti-Extractable Nuclear Antigens antibodies). The role of anti-DFS70 in children is yet not established even though but it has also been reported with a remarkably high frequency in unhealthy children (localized scleroderma, juvenile dermatomyositis and uveitis); it has also been detected in 2.1% of healthy children. <h3>Objectives</h3> The aim of our observational study is to evaluate the correlation between uveitis and anti-DFS70 antibodies in children with JIA. <h3>Methods</h3> 36 paediatric patients (24 females, 12 males) affected by JIA admitted to the Rheumatology Unit of Verona were evaluated. For each patient the following data were analysed: JIA subtype, ANA positivity, anti-DFS positivity, presence of uveitis diagnosed by a pediatric ophthalmologist. <h3>Results</h3> In our series oligoarticular ANA + JIA was the predominant subtype (25 cases, 70% of total JIA cases), followed by oligoarticular ANA – subtype (6 cases, 16.5% of total), poliarticular ANA – subtype (3 cases, 8% of total) and poliarticular ANA + (2 cases, 5.5% of total). All 6 patients (16.5%), who developed mono- or bilateral uveitis, were affected by oligoarticular ANA + JIA and presented DFS ANA pattern, confirming the evidence that DFS ANA pattern is the most common pattern associated with uveitis. Only one patient presented anti-ENA antibodies encompassing anti-DFS70 positivity. None of the other five patients presented antibodies anti-DFS70, regardless of the clinical history of uveitis. <h3>Conclusion</h3> DSF ANA pattern remains the most common pattern seen in JIA patients and seems to be an hallmark of uveitis. In our series we found that neither JIA nor the risk of uveitis in JIA correlates with anti-DFS70 isolated positivity. The role of these antibodies in children remains unclear. Further studies are necessary to identify a reliable biomarker to guide ophthalmologic screening in JIA patients in order to identify children likely to develop uveitis. <h3>References</h3> [1] Conrad K, et al. The Clinical Relevance of Anti-DFS70 Autoantibodies. Clinic Rev Allerg Immunol. 2017; 52: 202. [2] Malyavantham K, et al. Analysis of DFS70 pattern and impact on ANA screening using a novel HEp-2 ELITE/DFS70 knockout substrate. Auto Immun highlights 2017; 8: 3 [3] Mariz, et al. Pattern on the antinuclear antibody-HEp-2 is a critical parameter for discriminating antinuclear antibody-positive healthy individuals and patients with autoimmune rheumatic diseases. Arthritis Rheum 2011; 63: 191. [4] Mahler M, et al. Anti-DFS70/LEDGF antibodies are more prevalent in healthy individuals compared to patients with systemic autoimmune rheumatic diseases. J Rheumatol 2012; 39: 2104. <h3>Disclosure of Interests</h3> None declared