Furthermore, the activities of other antioxidant enzymes, including glutathione peroxidase 4 (GSH-Px4), glutathione reductase (GSSG-R) and thioredoxin reductase (Trx-R), are inhibited in the plasma of patients with psoriasis; the degree of which depends on the type of disease (psoriasis vulgaris vs. psoriatic arthritis) [19,20]. This evidence concerns the gene GPX4 and psoriatic arthritis.