Relative Levels of the Inflammatory Cytokine TNFα and the Soluble CD40 Ligand Profile in Serum Correlate with the Thyrotoxic Activity of Graves' Disease

Background: Interactions between CD40 and its ligand (CD40L) have important roles in T-cell-dependent activation of B cells, which may be related to the thyrotoxic activity of Graves' disease (GD). Soluble forms of CD40 ligand (sCD40L) are released from activated T cells and platelets, and several types of inflammatory cytokines are increased in patients with hyperthyroid GD. The aim of this study was to assess sCD40L and other cytokines as clinical indicators of disease activity or as possible markers of remission in GD. Methods: Serum levels of sCD40L, interleukin 18 (IL-18), tumor necrosis factor-alpha (TNFα), and TNFα receptors 1 and 2 (TNFR1 and TNFR2) were investigated in patients with active GD (GD-A), intractable GD (GD-IT), inactive GD (GD-IA), GD in remission (GD-R), and Hashimoto's thyroiditis (HT), and in control subjects (CON). Results: Serum concentrations of sCD40L were higher in the GD-A and GD-IT groups than in the HT and CON groups. Similarly, serum concentrations of IL-18, which induces...