Autoantibody tests in autoimmune thyroid disease: a case-control study

Both positive antinuclear antibody (ANA) and anti-DNA antibodies have been reported in patients with autoimmune thyroid disease. We sought to determine the frequency of ANA and other autoantibodies in autoimmune thyroid disease versus control subjects. We measured ANA by 2 methods (mouse liver, HEp-2), anti-dsDNA, anti-Ro, anti-La, anti-Sm, anti-RNP, and anticardiolipin in 26 patients with Hashimoto's thyroiditis, 26 patients with Graves' disease, and 26 control patients. Positive ANA by either method were more common in patients with Graves' disease than in controls (p = 0.002 and 0.05). Although common (46.2%), ANA by HEp-2 method was not found significantly more often in patients with Hashimoto's thyroiditis than in controls. Evidence for systemic autoimmune diseases was not found: patients with autoimmune thyroid did not have autoantibodies other than ANA and did not differ from controls in rheumatologic symptoms. Positive ANA using the widely accepted HEp-2 method were commonly found in both Graves' disease and Hashimoto's thyroiditis. No evidence of subclinical systemic autoimmune disease was found, either by specific autoantibody tests or by increased frequency of rheumatologic symptoms or signs.