The autoantibodies anti-SS-A, which is identical to anti-Ro, and anti-SS-B, which is identical to anti-La, have been found in patients with SLE, Sjögren's syndrome and other autoimmune diseases (67, 68). Both antibodies are also produced locally in the salivary glands as a consequence of local inflammation and can be measured therefore not only in plasma but also in saliva (69).
In addition, especially anti-SS-A/Ro antibodies have been found in mothers who had infants with congenital complete heart block (CHB), including some with SLE or Sjögren's syndrome as well as in mothers with no evidence of connective tissue disease (70, 71). There is some evidence that both antibodies might be actively involved in the pathogenesis of CHB (72). It has been suggested that anti-SS-A/Ro and anti-SS-B/La antibodies should be measured in pregnant patients with SLE to raise an index of suspicion of CHB in the fetus. Anti-SS-A/Ro antibody is suggested to influence the development of neonatal LE with CHB, whereas anti-SS-B/La antibody influences the development of cutaneous neonatal LE (73). However, the absence of anti-Ro does not exclude the possibility of congenital heart block.