Systemic erythematous lupus after treatment of multiple sclerosis with alemtuzumab.

Alemtuzumab is a humanized monoclonal antibody targeting CD52 protein that has shown great efficacy in the treatment of relapsing remitting multiple sclerosis and is associated with prolonged remission of the disease. Although it is highly effective, alemtuzumab can lead to serious adverse advents among which the most common are secondary autoimmune diseases. We present a patient who was treated with alemtuzumab for relapsing remitting multiple sclerosis. Her disease remained stable in a follow-up period of over ten years. However, during the follow-up period she developed thyroiditis one year, as well as systemic erythematous lupus seven years after the last alemtuzumab infusion, a disease not previously associated with alemtuzumab administration.