Common causative infections include Tuberculosis Bronchiectasis Osteomyelitis Leprosy Predisposing inflammatory conditions include Rheumatoid arthritis Juvenile idiopathic arthritis Crohn disease Inherited periodic fever syndromes such as familial Mediterranean fever Castleman disease Inflammatory cytokines (eg, interleukin [IL] - 1, tumor necrosis factor [TNF], IL-6) that are produced in these disorders or ectopically by tumor cells cause increased hepatic synthesis of serum amyloid A (SAA).