LAUSR

Biologic agents are being increasingly used in pediatric rheumatology, particularly TNF antagonists but also abatacept, tocilizumab, interleukin (IL)-1 antagonists and some other drugs. In Juvenile Idiopathic Arthritis (JIA) and some autoinflammatory diseases, data from phase 3 and extension trials or from cohorts such as Pharmachild allow to prospectively collect information on adverse events “of special interest”, including autoimmune complications. A few patients develop autoimmune/dysimmune features while on biologics, as seen in adults, including central nervous system lesions, inflammatory bowel disease or psoriasis. In addition, in patients with systemic-onset JIA, anti- IL-1 treatment is usually associated with the appearance of a type 1 interferon signature (gene expression analyses) which might in some cases favour lupus-like autoimmune features. On the other hand, among patients with early-onset arthritis, vasculitis, recurrent fever or other inflammatory manifestations, an increased number of children are diagnosed with complex monogenic diseases resulting in auto-inflammation, immune deficiency and autoimmunity. In such cases, biologics might not be responsible for the occurrence of autoimmune features that may sometimes be diagnosed on treatment. This distinction is important as biologics are useful treatments also in some of these patients, as was shown in patients with a diagnosis of Systemic-onset JIA and ANCA-associated glomerulonephritis in whom anti-IL-1 treatment was beneficial. It was also more recently shown in patients with lipopolysaccharide-responsive beige-like anchor (LRBA) mutations associated with autoimmunity and inflammation, including polyarthritis: as LRBA is a partner of cytotoxic-T lymphocyte antigen-4 (CTLA4),. abatacept has been used as a targeted treatment and shown efficacy. We hence aim to discuss the way to explore patients who develop autoimmune features while on biologics in order to take the right decisions regarding treatment maintenance, withdrawal or modification and regarding patients follow-up. Disclosure of Interest P. Quartier Grant/research support from: Abbvie, Novartis, Pfizer, Roche, Consultant for: Abbvie, Novartis, Sanofi, SOBI, Speakers bureau: Abbvie, BMS, Novartis, PfiZer, Roche, SOBI