Circulating IL-37 levels have been found to positively correlate with levels of CRP and/or ESR in patients with rheumatoid arthritis (18, 21–23), systemic lupus erythematosus (30), adult-onset Still’s disease (69, 70), ankylosing spondylitis (25), gout (71), and osteoarthritis (72), as well as in patients with chronic heart failure (38). Here, CRP is linked to congestive heart failure.