Farah Al-Ansari1, Hooshang Lahooti1,2, Leanne Stokes3, Senarath Edirimanne1,2, Jack Wall1,2. 1. a Department of Academic Medicine , Sydney Medical School, Nepean, The University of Sydney , Kingswood , Australia. 2. b Department of Endocrinology, Nepean Hospital , Nepean Blue Mountains Local Health District , Kingswood , NSW , Australia. 3. c School of Pharmacy , University of East Anglia , Norwich , United Kingdom.
Abstract
Purpose/aim of the study: Graves' ophthalmopathy (GO) is closely related to the thyroid autoimmune disorder Graves' disease. Previous studies have suggested roles for thyroidal CD8+ T cells and autoimmunity against calsequestrin-1 (CASQ)-1 in the link between thyroidal and orbital autoimmune reactions in GO. A role for autoimmunity against CollXIII has also been suggested. In this study, we aimed to investigate correlations between some thyroidal and peripheral blood T-cell subsets and thyroidal T-cell reactivity against CASQ1 and CollXIII in patients with GO. MATERIALS AND METHODS: Fresh thyroid tissues were processed by enzyme digestion and density gradient to isolate mononuclear cells (MNCs). Peripheral blood MNCs were also isolated using density gradient. Flow-cytometric analysis was used to identify the various T-cell subsets. T -cell reactivity to CASQ1 and CollXIII was measured by a 5-day culture of the MNCs and BrdU uptake method. RESULTS: We found a positive correlation between thyroidal CD8+ T cells and CD8+ T-regulatory (T-reg) cells in patients with GO. Thyroidal T cells from two out of the three patients with GO tested (66.7%) showed a positive response to CASQ1, while thyroidal T cells from none of the six Graves' Disease patients without ophthalmopathy (GD) tested showed a positive response to this antigen. Thyroidal T cells from these patient groups however, showed no significant differences in their response to CollXIII. CONCLUSIONS: Our observations provide further evidence for a possible role of thyroidal CD8+ T cells, CD8+ T-reg cells and the autoantigen CASQ1 in the link between thyroidal and orbital autoimmune reactions of GO.
Purpose/aim of the study: Graves' ophthalmopathy (GO) is closely related to the thyroid autoimmune disorder Graves' disease. Previous studies have suggested roles for thyroidal CD8+ T cells and autoimmunity against calsequestrin-1 (CASQ)-1 in the link between thyroidal and orbital autoimmune reactions in GO. A role for autoimmunity against CollXIII has also been suggested. In this study, we aimed to investigate correlations between some thyroidal and peripheral blood T-cell subsets and thyroidal T-cell reactivity against CASQ1 and CollXIII in patients with GO. MATERIALS AND METHODS: Fresh thyroid tissues were processed by enzyme digestion and density gradient to isolate mononuclear cells (MNCs). Peripheral blood MNCs were also isolated using density gradient. Flow-cytometric analysis was used to identify the various T-cell subsets. T -cell reactivity to CASQ1 and CollXIII was measured by a 5-day culture of the MNCs and BrdU uptake method. RESULTS: We found a positive correlation between thyroidal CD8+ T cells and CD8+ T-regulatory (T-reg) cells in patients with GO. Thyroidal T cells from two out of the three patients with GO tested (66.7%) showed a positive response to CASQ1, while thyroidal T cells from none of the six Graves' Disease patients without ophthalmopathy (GD) tested showed a positive response to this antigen. Thyroidal T cells from these patient groups however, showed no significant differences in their response to CollXIII. CONCLUSIONS: Our observations provide further evidence for a possible role of thyroidal CD8+ T cells, CD8+ T-reg cells and the autoantigen CASQ1 in the link between thyroidal and orbital autoimmune reactions of GO.