Annexin A5 is a member of Ca 2+-dependent phospholipid binding proteins family .It exists in histocytes . And because of its unique structure , Annexin A5 plays an important role in many critical functions such as cell in-side/outside anticoagulation and pro-apoptosis .Moreover , Annexin A5 has certain relevance with many diseases such as systemic lupus erythematosus ,tumour and other diseases .