Low-dose cyclosporin A induces relapsing remitting experimental allergic encephalomyelitis in the Lewis rat.

Experimental allergic encephalomyelitis (EAE) in Lewis rats is an acute monophasic autoimmune disease. It can be treated prophylactically and therapeutically with high doses of cyclosporin A (CsA). Here we demonstrate that low-dose CsA does not prevent a first attack of EAE, but, on the contrary, induces a chronic relapsing form of the disease in 100% of Lewis rats examined. Possible explanations for the high relapse rate after low-dose CsA treatment are discussed. Further studies will be needed to evaluate the immunological mechanisms responsible for these results.