Abstract
We previously reported that interleukin-5 (IL-5), secreted from Th2 cells, was increased in patients with Graves' disease, but not in patients with silent thyroiditis. In this study, we investigated serum levels of interleukin-12 (IL-12) in order to examine the role of Thl-type immune response in the pathogenesis of autoimmune thyroid diseases. Serum levels of IL-12 were determined by a highly sensitive sandwich enzyme-linked immunosorbent assay in 68 patients with Hashimoto's thyroiditis (26 of whom had silent thyroiditis), 74 patients with Graves' disease, 8 patients with subacute thyroiditis, and 27 normal controls. Serum levels of IL-12 in thyrotoxic patients with silent thyroiditis (385.2 ±164.5 pg/mL, mean ± SD), and in thyrotoxic patients with Graves' disease (343.6 ± 163.8 pg/mL) were significantly increased compared with serum levels in normal subjects (163.9 ± 66.8 pg/mL, p < 0.0001, p < 0.0001, respectively) or in thyrotoxic patients with subacute thyroiditis (241.9 ± 46.5 pg/mL, p < 0.01, < 0.05, respectively). The ratio of IL-12 to IL-5 in thyrotoxic patients with silent thyroiditis (64.2 ± 39.7) was significantly higher than that in normal controls (33.7 ± 13.3, p < 0.01) or in thyrotoxic patients with Graves' disease (40.6 ± 36.0, p < 0.05). These data suggest that Thl-type immune response is predominant in silent thyroiditis, and that not only Th2-type immune response but also Thl-type immune response is important in the pathogenesis of Graves' disease.
Get full access to this article
View all access options for this article.