Antibodies to Yersinia enterocolitica serotype 3 in autoimmune thyroid diseases.

The prevalence of increased titres of antibodies to Yersinia enterocolitica (serotype 3) has been studied in sera from patients with various thyroid diseases. In contrast to the low prevalences of the antibodies in healty subject (24.3%), titres (greater than 10) of anti-Yersinia enterocolitica (anti-Yersinia) were found more frequently in patients with thyroidal disorders, especially in Graves' disease (70.0%). Furthermore, high titres of the antibodies (greater than or equal to 160) were found only in patients with Graves' disease. There was no significant correlation between the titers of anti-Yersinia antibodies and those of anti-TSH receptor antibodies in sera from patients with Graves' disease. In seven individual samples of sera, the anti-Yersinia antibody titer was high before treatment, but the decrease in the anti-TSH receptor antibody titer following treatment was associated with a simultaneous decline in anti-Yersinia antibodies in all of them. A highly positive and significant correlation between the titers of anti-TSH receptor antibodies and anti-Yersinia antibodies was obtained in each of them. These findings could be merely a reflection of the measurement of the cross-reaction of anti-Yersinia antibodies with anti-TSH receptor antibodies but the possibility of an association between Yersinia infection and the production of anti-TSH receptor antibodies in at least some patients with Graves' disease cannot be ruled out.