Serum immunoglobulin G antibodies against H pylori (enzyme-linked immunosorbent assay), CagA protein (Western blot assay), circulating antibodies to thyroid antigens, mainly thyroperoxidase (TPOAbs) and thyroglobulin (TgAbs), were tested in 101 females with HT and 111 non-HT control women without a history of autoimmune disease. The gene discussed is TPO; the disease is autoimmune disease.