SAA2 and ankylosing spondylitis: Therefore, it is not surprising that accumulating evidences suggests SAA as a more reliable biomarker than CRP or ESR for monitoring disease activity in various rheumatic and autoinflammatory diseases, including rheumatoid arthritis (RA), ankylosing spondylitis (AS), juvenile idiopathic arthritis (JIA), systemic lupus erythematosus (SLE), different types of vasculitis, sarcoidosis, familial Mediterranean fever (FMF), secondary amyloidosis, etc., especially in the era of biologic immunosuppressive therapy.