Association of Graves’ Disease and Prevalence of Circulating IFN-γ-producing CD28⁻ T Cells

Peripheral blood CD4⁺ and CD8⁺ T-cell subsets lacking surface CD28 have been suggested to predispose patients to immune-mediated disorders.

To determine the role of CD28⁻ T-cell subset in Graves’ disease (GD), we characterized peripheral blood CD4⁺CD28⁻ and CD8⁺CD28⁻ T cell from early onset GD patients.

GD patients had significantly higher percentages of CD4⁺CD28⁻ and CD8⁺CD28⁻ T cells than did healthy donors. Both CD28⁻ T cells expressed mostly CD45RO, suggesting that they are activated and/or are memory T cells. GD patient-derived CD4⁺CD28⁻ and CD8⁺CD28⁻ T cells produced more intracellular IFN-γ than their counterparts from healthy donors. Furthermore, CD4⁺CD28⁻ and CD8⁺CD28⁻ T cells from GD patients with Graves’ ophthalmopathy (GO) secreted higher level of intracellular IFN-γ than those CD28⁻ T cells from GD patients without GO. Retrospective analysis showed that the increased levels of CD4⁺CD28⁻ T cells and their IFN-γ-producing subgroups were positively correlated to the serum anti-thyrotropin receptor (TSHR) autoantibodies (TRAb). Our observations suggest that increased IFN-γ-producing CD28⁻ T cells in GD patients may play an important role in the pathogenesis of GD.