Anti-SS-A (Ro) antibody

The epitope recognized by anti-SS-A (Ro) is located on two proteins (60 & times; 103 and 52 & times; 103) that form complexes with small RNAs hY1, hY3, hY4, and hY5 in the cell. The function of this ribonucleic acid protein particle is currently unknown, and the autoantibodies in the patient's serum may be directed against one, or more commonly, against two protein complexes. From a molecular biology point of view, the two proteins and their genes are highly conserved and have characteristic duplications, and there is no close relationship between the two. Therefore, the presence of antibodies against both proteins is not due to cross-reactivity.