The aim of this study was to estimate intracellular INF-γ and IL-4 levels in thyroid-infiltrating lymphocytes and thyrocytes isolated from thyroid tissues in 54 adolescent patients aged 8-21 years, with Graves' disease (GD; n = 18), Hashimoto's thyroiditis (HT; n = 18) and non-toxic multinodular goiter (NTMG; n = 18). This evidence concerns the gene IL4 and hematocrit.