A novel autoantibody, directed to citrullinated antigens in the synovium, seems to provide a new starting point.

• 近年来发现抗核周因子（AFP），抗角蛋白抗体（AKA）和抗聚角蛋白微丝蛋白抗体（AFA）对RA诊断的特异度高，新近认为上述抗体的表位都含有瓜氨酸，故称之为瓜氨酸相关自身免疫系统。