Multiple immune disorders after natalizumab discontinuation: After the CIRIS, the SIRIS?

Natalizumab (NTZ) is an effective treatment for patients with highly active relapsing remitting multiple sclerosis (MS). However, when the therapy must be interrupted, it is important to anticipate the withdrawal to avoid reactivation or disease rebound. Described here is the case of a 35-year-old woman, with a past history of beta thalassemia, bulimia and asthma, who was diagnosed with MS at age 26. She was treated initially with first-line subcutaneous (sc) immunomodulatory treatments. However, due to liver toxicity, interferon beta-1a sc was interrupted and replaced by glatiramer acetate treatment, which was well tolerated and used for several years. Unfortunately, disease progression with numerous relapses and contrast enhancement on brain MRI led to initiation of NTZ treatment. After more than 2 years of treatment, NTZ was interrupted because of pregnancy, and the patient was again put on glatiramer acetate. Eight weeks after interruption of NTZ therapy, the first signs of diabetes were observed, together with an increase in blood levels of hepatic enzymes, skin reactions such as angioedema and giant urticaria, and hypothyroidism requiring hormone supplementation. The patient delivered her baby without complications, and NTZ was reintroduced several months later. At the present time, the patient's hypothyroidism, diabetes and increased blood levels of hepatic enzymes persist, although no new skin reactions have been observed. Withdrawal of NTZ can not only lead to reactivation of the disease or its rebound, but also to autoimmune manifestations within the framework of immune reconstitution inflammatory syndrome (IRIS). This risk needs to be considered when therapy has to be interrupted, especially when a personal and/or familial past history of autoimmune disease is present.