BACKGROUND: DNA-hydrolyzing IgG antibodies have been detected recentlyin the sera of patients with several autoimmune diseases.
MATERIAL AND METHODS: The relative activityof DNA-hydrolyzing IgG from the sera of patients with Hashimoto's thyroiditis and with non-toxic nodalgoiter as a function of the patient's condition were measured. The effect of different drugs on the levelof DNA-hydrolyzing IgG, functional activity of thyroid gland, and improvement of clinical condition oftwo groups of patients were analyzed.
RESULTS: We demonstrate here for the first time that IgG from peripheralblood of patients with Hashimoto's thyroiditis (65%) and non-toxic nodal goiter (38%) possesses DNAseactivity. The relative level-specific activity of IgGs in hydrolysis of DNA increases with the enhancementof the relative amount of antibodies against thyroglobulin and all patients with hypothyroidism (namelya reduced concentration of thyroxine and triiodothyronine and enhanced level of thyrotropic hormone)are characterized by a high level of catalytic antibodies.
CONCLUSIONS: The very widely used therapyof patients with thyroxine led only to a temporary change of the hormone concentration in the blood butdid not affect the level of DNA-hydrolyzing antibodies. However, treatment with an immunosuppressivedrug plaquenil (7-chloro-4(beta-diethylamine-alpha-methylbutylamie)quinoline), significantly decreasedthe DNA-hydrolyzing activity of Abs, which correlated with enhancement of thyroid hormone concentrations,elevation of functional activity of the thyroid gland, and improvement of the clinical state of the patients.

Keywords: Hashimoto, nontoxic nodal goiter, catalytic antibodies, DNAse activity, different drug treatment