RESUMO
BACKGROUND: DNA-hydrolyzing IgG antibodies have been detected recently in the sera of patients with several autoimmune diseases. MATERIAL AND METHODS: The relative activity of DNA-hydrolyzing IgG from the sera of patients with Hashimoto's thyroiditis and with non-toxic nodal goiter as a function of the patient's condition were measured. The effect of different drugs on the level of DNA-hydrolyzing IgG, functional activity of thyroid gland, and improvement of clinical condition of two groups of patients were analyzed. RESULTS: We demonstrate here for the first time that IgG from peripheral blood of patients with Hashimoto's thyroiditis (65%) and non-toxic nodal goiter (38%) possesses DNAse activity. The relative level-specific activity of IgGs in hydrolysis of DNA increases with the enhancement of the relative amount of antibodies against thyroglobulin and all patients with hypothyroidism (namely a 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 therapy of patients with thyroxine led only to a temporary change of the hormone concentration in the blood but did not affect the level of DNA-hydrolyzing antibodies. However, treatment with an immunosuppressive drug plaquenil (7-chloro-4(beta-diethylamine-alpha-methylbutylamie)quinoline), significantly decreased the 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.
