PTX3 and lupus nephritis: Though a molecule as a biomarker might not participate in the pathogenesis of disease, we believed that PTX3 should be involved in the progression of lupus nephritis based on the following reasons: As having multiple complex nonredundant functions, PTX3 was mainly involved in the regulation of inflammatory reactions and the maintenance of immunologic tolerance, which were 2 important fields in the mechanism of lupus nephritis.