Antineutrophil cytoplasmic antibodies in autoimmune thyroid disorders

Different antibodies against both organ- and non-organ-specific autoantigens have been found in patients with autoimmune thyroid diseases. The aim of our study was to evaluate the presence of antineutrophil cytoplasmic antibodies (ANCA) in sera of patients affected by Graves' disease (GD) and Hashimoto's thyroiditis (HT). These antibodies were investigated by indirect immunofluorescence; the reactivity against myeloperoxidase and lactoferrin was assessed by ELISA. ANCA were detected by immunofluorescence in 28.5% of patients with GD and 9% of patients with HT. Anti-lactoferrin antibodies were found in 3 of 21 (14.2%) patients affected by GD and in 2 of 11 (18.1%) cases of HT. Anti-myeloperoxidase antibodies were detected only in one (4.7%) patient with GD.