PGRN-Abs are also detected with around 20% of psoriatic arthritis patients and serum levels of PGRN are significantly lower in PGRN-Abs positive patients compared with PGRN-Abs negative patient, indicating that this neutralizing PGRN Abs provides a proinflammatory environment in psoriasis patients (Thurner et al., 2013a; Thurner et al., 2013b). Here, GRN is linked to psoriatic arthritis.