PTX3 and systemic lupus erythematosus: Increased levels of serum PTX3 have been found in a set of inflammatory autoimmune disorders, such as rheumatoid arthritis and small vessel vasculitis.14,15 Interestingly, limited studies found that patients with SLE presented with lower serum PTX3 levels even compared with normal controls.15,16 Abundance of PTX3 was found at sites of leukocytoclastic lesions in patients with small vessel vasculitis.17