The kinetics of cytokine gene expression in the thyroids of mice developing granulomatous experimental autoimmune thyroiditis

To study the potential roles of cytokines in development and resolution of granulomatous experimental autoimmune thyroiditis (EAT), the kinetics of in vivo expression of cytokine genes in thyroid infiltrates was analysed usin g reverse transcriptase-PCR (RT-PCR). Both Th1 (IL-2 and IFN-gamma) and Th2 (IL-4 and IL-10) cytokines as well as TGF-beta, TNF-alpha, IL-12 and IL-1 beta were detected in thyroids during both the initial phase and peak of gr anulomatous EAT. Maximal expression of cytokine genes generally occurred 11 -14 days after cell transfer, prior to maximal EAT severity, which occurred 19-21 days after cell transfer. The relative ratios of Th1:Th2 cytokines a nd mouse thyroglobulin-(MTg)-specific IgG1 and IgG2a autoantibody levels we re similar during both the initial phase and peak of EAT. Depletion of CD8( +) T cells did not decrease the severity of EAT but delayed resolution of l esions. Cytokine gene expression in thyroids was not decreased by anti-CD8 treatment. Together, these data indicate that both Th1 and Th2 cytokines pr oduced by CD4(+) T cells are involved in induction and development of granu lomatous EAT, and CD8-dependent resolution of granulomatous EAT is apparent ly not mediated by these cytokines. (C) 1998 Academic Press.