GRN and psoriasis: The role of progranulin in the inflammatory process of several autoimmune diseases remains controversial: its pro‐inflammatory action was reported to exhibit a significant correlation with granulin levels and disease activity in systemic lupus erythematosus (SLE) and systemic sclerosis, whereas its anti‐inflammatory action was known to be implicated in rheumatoid arthritis (RA), inflammatory bowel disease, and psoriasis.4, 6