Introduction: Liver diseases are still a serious public health problem worldwide because of 
significant morbidity and mortality. Aim of the work: The aim of the work was to show the effect of 
Cyclosporine (calcineurin inhibitor) on altered hepatic function associated with silica-induced 
autoimmune hepatitis in rats and to study its mechanism through studying the effect on expression of 
toll-like receptor - 4 and interleukin- 2 in liver tissue by real-time PCR. Materials and methods: 
Animals: Seventy adult Wistar male rats (weighing 150-350g) were used for this study. Animals were 
acclimated for 72 hours before initiation of the study. All animal care and procedures were in 
compliance with the National Institutes of Health Guidelines for the care and use of laboratory 
animals. Results: Comparison of the levels of liver enzymes in the study groups: The obtained 
results indicated that serum level of ALT and AST among all groups were statistically highly 
significant (ANOVA, p- value < 0.001). Recommendation: Collectively, our data imply that there 
are other mechanisms involved in mediating the effects of cyclosporine in amelioration of silicainduced autoimmune hepatitis. Exploring these unknown mechanisms needs further studies to be 
elucidated and to help in the possibility of establishing cyclosporine as one of the therapeutic agents 
of autoimmune hepatitis.