Is it important to define titres for HEp-2 IFA?

The presence of high titer IgG autoantibodies and their persistence over time is characteristic of several autoimmune rheumatic diseases, such as SLE, scleroderma, Sjögren’s syndrome, mixed connective tissue disease and autoimmune liver disease (PBC, autoimmune hepatitis). High titer autoantibodies should not be regarded as epiphenomenona of infection or inflammation. However, autoantibodies at low titers (<1:80) may be present in patients with various non-autoimmune diseases (viral and bacterial infections, neoplasia, etc.), in relatives of patients with autoimmune diseases and in apparently healthy subjects MitogenDx has set a fixed cut-off for positivity at a titer of 1:80 to decrease the percentage of false positives. A large multicenter study has shown that ANA without any clinical significance may be found in 30% of healthy subjects at a titer of 1:40 and in 5% at a titer of 1: 160 (6).