Anti-SS-A 52kD Ab, IgG (RDL)

The presence of these antibodies, when considered in conjunction with other laboratory and clinical findings, is an aid in the diagnosis of systemic lupus erythematosus (SLE), Sjögren’s Syndrome (SS), systemic sclerosis (SSC), polymyositis (PM) and dermatomyositis (DM). SS-A/Ro antigen are found in 40-60% of patients withSjögren’s Syndrome and in 25-35% of patients with SLE. At one time it was thought that two different proteins, SS-A 52 and SS-A 60, were needed to account for SS-A antigenic reactivity. Now it is known that SS-A 52 and SS-A 60 proteins are not linked in the same particle. In addition, anti-SS-A 52 autoantibodies are distinct from, and have a different clinical utility than, anti-SS-A 60 antibodies. Just like anti-SS-A 60, anti-SS-A 52 is commonly found in patients with SLE and Sjgren's Syndrome, and occasionally in other autoimmune disorders. However, anti-SS-A 52 autoantibodies are also found in patients with systemic sclerosis, polymyositis and dermatomyositis. Anti-SSA 52 are linked with antibodies to tRNA synthetases like Jo-1, PL-7, PL-12, EJ and OJ, which are often found in patients with interstitial lung involvement. Studies show that 10-45% of myositis is positive with SSA52 antibody. An RDL study revealed 38% of myositis patients (18/47) were positive for SS-A 52 antibody. RDL offers SS-A 52 antibody test as part of the myositis panel.