Prevention of diabetes mellitus in the BB/W rat with Cyclosporin-A.

Autoimmune diabetes mellitus occurs spontaneously in 40-60% of a colony of BioBreeding/Worcester rats. Pretreatment of susceptible animals for 10-day intervals prior to 70 days of age with Cyclosporin-A (CSA) significantly reduced the frequency and delayed the onset of diabetes. The relatively narrow time frame of successful treatment suggests that effector cells responsible for beta cell destruction in this model of Type I diabetes may be activated during this period of time prior to the onset of overt hyperglycemia. CSA administration did not protect against the occurrence of lymphocytic thyroiditis or autoantibodies directed against smooth muscle or thyroid colloid, suggesting that these BB immunologic phenomena may be controlled by a distinct series of immunologic events.