The ACPA response is different from conventional antibody responses. The ACPA response is generally of a much lower avidity than recall responses. Avidity maturation is limited and occurs before... Show moreThe ACPA response is different from conventional antibody responses. The ACPA response is generally of a much lower avidity than recall responses. Avidity maturation is limited and occurs before disease onset. The presence of low avidity ACPA is associated with higher rate of joint destruction. In vitro, the binding of low avidity ACPA to citrullinated epitopes was weakly inhibited by citrullinated antigens and low avidity ACPA have a higher ability to activate the complement system. In addition, there are certain antigens which continuously drive ACPA (IgM) response in RA. Show less
