Comparison of the Level of DNA-Hydrolyzing Polyclonal IgG Antibodies in Sera of Patients with Hashimoto's Thyroiditis and Nontoxic Nodal Goiter.

Various catalytically active IgG antibodies or abzymes have been recently detected in the sera of patients with several autoimmune pathologies, where their presence is most probably associated with autoimmunization. Here we show for the first time that IgG from peripheral blood of patients with Hashimoto's thyroiditis and nontoxic nodal goiter possesses DNase activity. The properties of the DNase IgGs distinguished them from other known human DNases.

Variability of Substrate Specificity of Serum Antibodies Obtained from Patients with Different Autoimmune and Viral Diseases in Reaction of tRNA Hydrolysis.

Recently we have shown that the substrate specificity of catalytic IgG isolated from sera of patients with Hashimoto's thyroiditis, systemic lupus erythematosus (SLE), polyarthritis and hepatitis B for classic poly(N) homopolynucleotide substrates and for specific tRNA(Phe) with compact and stable structure was correlated with the type of disease. At the same time the cleavage specificity was different in comparison with that of all known human RNases. Here we investigated for the first time the hydrolysis by the IgGs isolated from sera of 31 patients with different diseases of the in vitro transcript of human mitochondrial tRNA(Lys) which has less stable structure as compared to tRNA(Phe).