CD30 Expression and Interleukin-4 and Interferon-y Production of Intrathyroidal Lymphocytes in Graves' Disease

We reported that serum levels of interleukin-5 (IL-5) and soluble CD30, mainly secreted from T helper 2 (Th2) cells, were increased in Graves' disease. To clarify the immune balance of Thl/T_2 within the Graves' thyroid gland, we have compared the expression of CD30, a preferential marker for T cells producing type 2 cytokines, and the production of interferon-γ (EFN-γ) and IL-4 between intrathyroidal lymphocytes (ITL) and peripheral blood lymphocytes (PBL). In PBL, none of these parameters were different between patients and normal subjects. The proportion of CD30⁺ cells in ITL was markedly higher (5.1% ± 2.8%, p < 0.0001) than that in patients' PBL (0.4% ± 0.3%). Likewise, both the proportions of IFN-γ⁺ (14.8% ± 5.5%) and D.-4⁺ cells (2.4% ± 0.5%) in ITL were higher than those in PBL (9.6% ± 2.5%; p < 0.01, 1.5% ± 0.4%; p < 0.0001, respectively). The proportion of type 0 (both IFN-γ and IL-4 positive, 1.0% ± 0.4% p < 0.001), type 1 (IFN-γ positive, 14.0% ± 5.6%, p < 0.01) or type 2 cells (IL-4 positive, 1.4% ± 0.5%, p < 0.05) in ITL was significantly higher as compared with those in PBL (0.4% ± 0.1%, 9.0% ± 2.4%, 1.1% ± 0.3%, respectively). The ratios of ITL/PBL in CD30+ (23.3 ± 30.6) and type 0 cells (2.5 ± 1.2) were higher than the ratios in other subsets. The proportion of CD30⁺ cells correlated with the proportion of type 0 cells (r = 0.686, p < 0.01), but not with type 1 or type 2 cells. These findings suggest that there is no obvious deviation of Th2/Thl profile in the Graves' thyroid gland, although intrathyroidal CD30⁺ T cells and ThO cells may play some role in the development of autoimmune abnormalities in Graves' disease.