Our SECONDARY objectives are to evaluate the sensitivity, specificity, and +LR : 1- of anti-CCP and anti-Sa Abs (individually and in sets) to identify among patients with EPA those who will develop a SEVERE disease after 18, 30, 42, and 60 months; 2- of novel genetic markers to identify among patients with EPA those that will develop a SEVERE disease after 18, 30, 42, and 60 months; 3- of anti-Sa and anti-CCP Abs to identify among patients with EPA those patients who will require more intensive anti-rheumatic treatment (DMARD combinations and/or biologics) at 18, 30, 42 and 60 months; and 4- of serum and urine markers of cartilage degradation and regeneration to identify among patients with EPA those that will develop a SEVERE disease after 18, 30, 42, and 60 months.