NRAP and ankylosing spondylitis: Fig. 5 shows the results obtained. Anti-NRAP peptide antibodies were detected in 83/100 (83%) of the patients with PsA, in 7/100 (7%) patients with seropositive RA and in 4/100 (4%) patients with seronegative RA (Fig. 5A). No reactivity against the N-RAP peptide was detected in systemic sclerosis, Sjogren syndrome, systemic lupus erythemathosus and ankylosing spondylitis, while one out of thirthy sera of patients affected by psoriasis (Ps) bound the N-RAP peptide (Fig. 5B).