Transplantation of CTLA4Ig gene-transduced adipose tissue-derived mesenchymal stem cells reduces inflammatory immune response and improves Th1/Th2 balance in experimental autoimmune thyroiditis.

Background: Autoimmune thyroiditis is one of common organ-specific autoimmune disease. The aim of this study was to observe the effect of adipose tissue derived mesenchymal stem cells (ATMSC) and CTLA4Ig gene-transduced ATMSC on autoimmune thyroiditis.

Methods: Experimental autoimmune thyroiditis was induced by immunization with thyroglobulin. Animals were divided into three groups: (i) a half million of human ATMSC, (ii) a half million of murine CLTA4Ig gene-transduced human ATMSC (CTLA4Ig-MSC), or (iii) normal saline (as control), which were administered intravenously four times within a 3-week period. Blood and tissue samples were collected 1 week after the last cell transplantation.

Results: The absorbance of serum thyroglobulin autoantibody (TgAA) in the CTLA4Ig-MSC group was considerably lower than those in other groups. In culture supernatant of LPS-stimulated spleen cells, both of the MSC-treated groups showed significantly lower absorbances of TgAA than the control. Flow cytometric analysis of spleen cells revealed a significant decrease in the proportion of CD3+ and CD11b in the CTLA4Ig-MSC group compared to the other groups. Lymphocyte infiltration in the thyroid glands was also dramatically decreased in both of MSC-treated groups. Cytokine analysis showed that ATMSC decreased the production of proinflammatory cytokines and improved the Th1/Th2 balance by down-regulating Th1 cytokines.

Conclusion: Although CTLA4Ig-MSC transplantation had better result in reduction of serum TgAA, both of ATMSC and CTLA4Ig-MSC transplantations are promising treatments for autoimmune thyroiditis judging from the results of histopathology and cytokine analysis. They may be attractive candidates for treating organ-specific autoimmune disease.