Reinduction of experimental allergic encephalomyelitis in convalescent Lewis rats with cyclophosphamide.

Experimental allergic encephalomyelitis (EAE) in Lewis rats is an acute, monophasic autoimmune disease, and rats recovering from EAE are generally resistant to active reinduction. However, following immunosuppression with a high dose (100-200 mg/kg) of cyclophosphamide (CY), EAE was reinduced in convalescent rats, irrespective of whether or not they were rechallenged with the encephalitogenic inoculum. Reinduction of EAE was not observed in rats treated with low doses (20 mg/kg or less) of CY. A selective inhibition of suppressor cells during the convalescent stage may be responsible for the reinduction of EAE in Lewis rats.