Clinical and experimental evidence suggest that apart from cholesterol lowering, statins offer additional benefits via modulation of immune response. The immunological effects mediated by statins are due to their ability to partially inhibit a common denominator of multiple regulatory pathways. The modification of signal transduction proteins by isoprenoid intermediates generated by the mevalonate pathway is responsible for these effects. The inhibition of MHC class II upregulation by statins provides a rationale basis for therapeutically exploiting the pleiotropic effects of statins. Consequently, statin therapy may be considered an attractive approach in the treatment of autotoimmune diseases.