SSA/Ro Antibody (AI) Unit Converter

The SSA/Ro (ENA) Ab test measures autoantibodies directed against the SSA/Ro antigen, a type of extractable nuclear antigen (ENA). These antibodies are produced by the immune system when it mistakenly targets the body's own Ro proteins, which are found inside cells.

The SSA/Ro antigen actually consists of two distinct proteins: Ro60, which helps degrade misfolded RNA and protects cells from UV damage, and Ro52 (also called TRIM21), which is involved in inflammation and protein regulation. Standard assays typically detect antibodies against both proteins combined.

Results are reported as an Antibody Index (AI), with values at or below 0.9 AI considered normal. A positive result suggests the presence of autoimmune activity and warrants further evaluation.

Anti-SSA/Ro antibodies are produced by B lymphocytes and plasma cells of the immune system. Their production can be triggered by viral infections (particularly Epstein-Barr virus through molecular mimicry), UV-induced cell damage that exposes normally hidden Ro proteins, and genetic susceptibility factors such as certain HLA gene variants.