SEROREACTIVITY TO BACTERIAL-ANTIGENS IS NOT A UNIQUE PHENOMENON IN PATIENTS WITH AUTOIMMUNE THYROID-DISEASES IN CANADA

It has been suggested elsewhere that the enteric pathogen Yersinia ent eracolitica (Y.e.) might be implicated etiologically in autoimmune thy roid disease (AITD). To reevaluate this hypothesis in the Canadian pop ulation, where the prevalence of anti-Y.e. antibodies in the general p opulation is very low (<1%), we have studied the occurrence of antibac terial reactivity (against Y.e. 0:3 and 0:9, Escherichia coli and Stap hylococcus aureus) in the sera of patients with Hashimoto's thyroiditi s (HT), Graves' disease (GD), nontoxic nodular goiter (NTG), and autoi mmune rheumatic diseases (ARD) as well as normal controls (C). Using t he tube agglutination method, no single positive sample was detected i n these subjects. No differences in the mean levels of anti-Y.e. 0:3 o r 0:9 by ELISA were observed between various groups of patients. Immun oreactivity in the course of medical therapy during 5-12 months did no t show significant changes in any of 12 ARD and AITD patients. Some se rological reactivity to the plasmid containing strain of Y.e. 0:3 was demonstrated in all subjects by the Western blotting technique. Howeve r, weaker signals and fewer bands were noticed in these sera compared to sera from patients with acute yersiniosis. Analysis of the pattern of reactivity did not show any difference in reactivity to any protein between the groups of subjects. The immunodominant antigen in Y.e. 0: 3 to which IgG reacted in almost all subjects was the plasmid encoded 240-kDa protein. Our study favors the view that there is a merely coin cidental incidence of seroreactivity to bacterial antigens, which appe ars to be irrespective of diagnosis.