Thrombotic microangiopathy due to acquired ADAMTS13 deficiency in a patient receiving interferon-beta treatment for multiple sclerosis.

Thrombotic microangiopathies (TMAs) can be due to inherited or acquired ADAMTS13 deficiency. Acquired deficiency is mainly associated with autoantibodies directed to ADAMTS13, including drug-induced forms. A few cases of TMA have been reported in association with interferon-alpha treatment and more rarely with interferon-beta. We report the case of a 52-year-old male with TMA-associated severe renal failure secondary to severe ADAMTS13 deficiency due to an anti-ADAMTS13 IgG antibody which developed after interferon-beta treatment for multiple sclerosis. Treatment included interferon-beta discontinuation, immediate plasma exchange therapy, corticosteroids, and hemodialysis. After an initial hematologic improvement, early hemolysis relapse led us to introduce rituximab allowing durable hematologic recovery. This is the first reported case of interferon-beta-induced TMA due to acquired ADAMTS13 deficiency that was treated by rituximab.