Abstract
Chronic lymphocytic thyroiditis and vitiligo often occur in association and seem to be characterized by a prevalent Th1-driven autoimmune process. The aim of this study is to analyze selected intracellular Th1 and Th2 cytokines in patients with Hashimoto's thyroiditis when associated with non-segmental vitiligo. We analyzed intracellular interleukin-2, interferon-γ (Th1) and interleukin-4 (Th2), in peripheral blood lymphocytes of 23 patients with isolated Hashimoto's thyroiditis (group A) and of 11 patients with Hashimoto's thyroiditis associated with non-segmental vitiligo (group B). Peripheral blood lymphocytes were stimulated and incubated with specific monoclonal antibodies. Intracellular cytokines were assayed by flow cytometric analysis. Interleukin-2 and interferon-γ positive cells were increased in almost all patients but the median values were similar in patients with isolated Hashimoto's thyroiditis and in those with concurrent vitiligo. In contrast, the number of patients with increased interleukin-4 positive cells was higher in patients with thyroiditis and vitiligo (9/11) than in those with isolated thyroiditis (2/23; p<0.0001). The median values of IL-4 positive cells in the two groups confirmed this difference (A: 5.8%, vs B: 20.6%; p=0.0011). Increased interleukin-4 positive lymphocytes characterize Hashimoto's thyroiditis when associated with non-segmental vitiligo, suggesting a modified balance from highly prevalent Th1 to mixed Th1/Th2 subset.