A reduced IL2R (CD25) expression level in first and second degree female relatives of autoimmune thyroid disease patients. A sign of a poor capability to preserve tolerance?

• Published in: Autoimmunity (Chur, Switzerland) Switzerland), 2006-03, Vol.39 (2), p.93-98
• Main Authors: Strieder, Thea G.A., Drexhage, H.A., Lam-Tse, W.K., Prummel, M.F., Tijssen, J.G.P., Wiersinga, W.M.
• Format: Article
• Language: English
• Subjects: Adult; Autoantibodies - blood; Autoantigens - immunology; Autoimmune thyroiditis; Biological and medical sciences; Biomarkers - blood; Case-Control Studies; CD4-Positive T-Lymphocytes - immunology; CD4CD25; Cohort Studies; Female; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Fundamental immunology; General aspects; Humans; IL-2R; Immunopathology; Iodide Peroxidase - immunology; Iron-Binding Proteins - immunology; Lymphocyte Activation; Medical sciences; Middle Aged; Receptors, Interleukin-2 - blood; relatives; Risk Factors; Self Tolerance; T-Lymphocyte Subsets - immunology; Thyroiditis, Autoimmune - genetics; Thyroiditis, Autoimmune - immunology; treg
• ISSN: 0891-6934; 1607-842X
• DOI: 10.1080/08916930500508092

There is room for immune markers other than TPO-Abs to identify an increased risk to develop autoimmune thyroid disease (AITD). Our aim was to test the hypothesis that activation of CD4+T cells is such marker in relatives of AITD patients, who have an increased risk to develop AITD. We established a controlled study on 20 TPO-Ab positive and 20 TPO-Ab negative euthyroid female relatives. All these cases had at least one 1st or 2nd degree relative with a documented autoimmune hyper- or hypothyroidism in whom we studied the percentages of circulating subsets of activated (MHC class-II, CD25 (IL-2R), CD71 or CD69+) CD4+T cells and the level of the soluble (s)-IL2R in serum. We found that euthyroid female relatives did not show an activation of their T cell system, but a reduced expression of CD25 on CD4+T cells. The level of the shed IL2R in serum was also lower in comparison with levels found in healthy control females. A reduced T cell activity was found in both TPO-Ab positive and negative relatives. In conclusion, female relatives with at least one 1st or 2nd degree relative with an AITD show signs of a reduced expansion capability of their T cell pool. It is hypothesized that this reduced expansion capability may affect T cell tolerance mechanisms more than T effector mechanisms.