Previous exposure to measles, mumps, and rubella - But not vaccination during adolescence - Correlates to the prevalence of pancreatic and thyroid autoantibodies

Objective. This study was designed to determine whether a relationship exis ts between previous exposure to measles, mumps, and rubella (MMR) by natura l infection or vaccination or by new immunization with MMR vaccine, and eit her the presence or levels of autoantibodies against thyroid cell and pancr eatic beta-cell antigens. Methods. Antibodies against MMR and autoantibodies against thyroglobulin, t hyroid peroxidase, pancreas islet cells (ICA), islet cell surface, glutamic acid decarboxylase 65k autoantibodies, and insulin were studied before, an d 3 months after, vaccination with combined MMR vaccine in 386 school child ren between 11 and 13 years of age. Results. The vaccination changed neither the prevalence nor the level of au toantibodies. Children with rubella antibodies before vaccination had highe r levels of ICA than did the rubella seronegative children. In contrast, th yroid autoantibody levels and prevalence were lower in children with antibo dies against measles, mumps, or both before vaccination than in children wi thout those antibodies. Conclusions. Previous natural infection or vaccination against measles, mum ps, or both seemed to have an inhibitory effect on the development of thyro id autoantibodies. In contrast, children with previous exposure to rubella had higher levels of ICA. No evidence was found that MMR vaccination during adolescence may trigger autoimmunity.