Tacrolimus, but not cyclosporine A, significantly increases expression of ICAM-1 and IFN-gamma in the NOD mouse.

We studied the alterations of cytokines and ICAM-1 expression in the NOD mouse pancreas produced by the administration of Cyclosporine A (CY) and Tacrolimus (TA), two widely used immunosuppressive drugs. Results evidenced differences in the effects of these two drugs. In fact, during treatment and after withdrawal, CY-treated animals remained euglycemic, showed good islet cell preservation and had low levels of Th1 and Th2 cytokines; ICAM-1 positivity within the islets was also found to be relatively low. On the other hand, TA-treated animals had infiltrated islets containing numerous dendritic cells, adhesion molecule overexpression, increased IFN-gamma and ICAM-1 mRNA transcripts, and interestingly, high levels of circulating ICAM-1. However, even these animals remained euglycemic. These findings lead to the thought that these drugs may exert their effects in very different ways. Moreover, in TA-treated animals, the presence of an islet infiltrate containing numerous dendritic cells coupled with maintenance of euglycemia is suggestive for the involvement of immunosurveillance mechanisms. J. Cell. Biochem. Suppl. 36: 107-116, 2001.