High incidence of thyroiditis and anti-thyroid autoantibodies in NOD mice.

NOD mice develop spontaneous insulin-dependent diabetes mellitus (IDDM) associated with infiltration of pancreatic islets with mononuclear cells. Islet infiltration results in autoimmune destruction of insulin-secreting beta-cells. Because in humans and BB rats diabetes is often associated with autoimmune thyroid disease (ATD), the NOD mouse model was examined for evidence of thyroiditis and serum antibodies reactive with mouse thyroid membrane antigens (MTMAs). The incidence of thyroiditis was 77% in mice greater than 180 days old, 67% in mice 61-180 days old, 72% in mice 31-60 days old, 74% in mice 21-30 days old, 78% in mice 11-20 days old, and 90% in mice less than or equal to 10 days old. NOD mice less than or equal to 30 days old had less-severe thyroiditis than animals greater than 180 days old. There was no significant different in severity of thyroiditis between any of the other age-groups tested. The incidence of thyroiditis was not increased in diabetic compared with nondiabetic animals, nor was an association found between thyroiditis and sex. The high incidence of thyroiditis in the less than or equal to 30-day-old age-group indicates that infiltration of lymphocytes into the thyroid can precede initiation of insulitis in this model. Although both thyroiditis and insulitis in NOD mice began early (by the 1st and 2nd mo of life, respectively), no significant association between infiltration of these two organs was noted in individual mice.(ABSTRACT TRUNCATED AT 250 WORDS)