Antinuclear antibody positivity in pediatric patients with autoimmune thyroid disease.

Abstract

The incidence of antinuclear antibody (ANA) positivity was investigated in pediatric patients with autoimmune thyroid diseases. Subjects were 21 untreated patients with Graves' disease, 12 untreated patients with Hashimoto's disease, and 16 untreated patients with non-autoimmune thyroid disease, including one patient with Plummer's disease, 11 patients with simple goiter (probable), and 4 patients with cretinism. Patients with Graves' disease were treated with either propylthiouracil or methimazole. ANA was measured using HEp-2 cells. Anti-dsDNA antibody was measured using double stranded DNA derived from an Escherichia coli plasmid. The incidence of ANA positivity was significantly higher in patients with untreated Graves' disease (n = 21; age range 9-15 yrs) than in Hashimoto's thyroiditis (n = 12; age range 7-15 yrs) (p < 0.03, Fisher's exact probability test). However, the 2 diseases were not significantly different with respect to anti-dsDNA antibody positivity. Most of the ANA positive patients with Graves' disease required treatment for more than 2 years, unlike the 6 ANA negative patients (p < 0.002, Fisher's exact probability test). We conclude that ANA positivity may predict a poor response to antithyroid drugs in Graves' disease.