Rheumatoid factor positive polyarticular juvenile idiopathic arthritis associated with a novel COPA mutation. (2nd December 2020) - Bader-Meunier, Brigitte; Bustaffa, Marta; Iskounen, Thinhinane; Carter, Edwin; Marsh, Joseph A; Baujat, Geneviève; Crow, Yanick J; Frémond, Marie-Louise