PGRN plasma levels were significantly lower in PGRN Ab-positive patients with PsA (n = 10) compared to healthy controls (n = 10) (P < 0.001 by Mann-Whitney U test), patients with PsC (n = 10) (P < 0.001 by Mann-Whitney U test) and PGRN Ab-negative patients with PsA (n = 5) (P < 0.001 by Mann-Whitney U test). Here, GRN is linked to pancreatic serous cystadenoma.