Cytokine regulation of HLA on thyroid epithelial cells
The regulation of class I and class II HLA expression in human thyroid follicular cells was studied in vitro. Tumour necrosis factor‐alpha (TNF‐α) enhanced the expression of class I antigen on thyrocytes, but these cytokines had little effect on the expression of class II antigen. Interleukin‐lβ (IL‐ lβ) and interleukin‐6(IL‐6) did not affect class I and class II antigen expression. The combination of interferon‐gamma (IFN‐γ) with TNF‐α or IL‐1β enhanced the induction of class I and class II antigens, compared with the effect of IFN‐β alone. Neither class I nor class II expression was induced by lL‐6 alone or in combination with IFN‐γ. These findings suggest that TNF‐α and IL‐1β may have an important role in inappropriate expression of HLA antigens on thyrocytes in thyroid gland.