Michael Carrithers: Maintaining Immune Surveillance
O
ur goals are to develop new and safer treatments for patients with all forms of multiple sclerosis,” said Dr. Michael Carrithers, an associate professor of neurology at the University of Wisconsin School of Medicine and Public Health.
it’s relevant for patients. For example, some patients developed progressive multifocal leukoencephalopathy (PML) while on natalizumab (brand name Tysabri, an
Dr. Carrithers practices at the University of Wisconsin Hospital and Clinics and the William S. Middleton Veterans Hospital. He began studying MS in 1997, while he was at Yale University. He received a $306,292 grant from the Dr. Michael Carrithers’ goal is to National Multiple Sclerosis develop treatments for people Society in 2008 to study with MS. immune surveillance and injection used to treat people migration of cells in the with relapsing-remitting MS). brain and spinal cord. Natalizumab slows the movement of immune cells to What is Immune prevent them from crossing the Surveillance? blood-brain barrier into the Immune surveillance is the brain and spinal cord. While process where the immune this can prevent damage to system monitors the body for the brain and spinal cord, pathogens such as viruses and it hinders normal immune parasites. In normal immune surveillance, potentially leavsurveillance, the immune ing patients open to infections system differentiates between such as PML, a rare disease what belongs in the body and that is sometimes fatal. There what does not. In MS and is about a 1-in-1,000 risk for other autoimmune diseases, developing PML for patients the immune system attacks treated with Tysabri. what belongs in the body. According to Dr. Carrithers, immune surveillance is “clinically relevant,” meaning MS Connection | 6
Symptoms of PML include clumsiness, weakness on one side of the body, vision
changes, confusion and changes in personality. “Patients were started on natalizumab and some developed PML,” Dr. Carrithers said. “Unfortunately, this was proof of the concept that immune surveillance was important to the clinical treatment of MS. Without normal immune surveillance, patients can have life-threatening infections.” Dr. Carrithers addresses this lack of normal immune surveillance in his research. “The goal is to identify factors that may mediate or repair normal immune surveillance of the brain, while also being able to keep out the disease causing cells,” he explained. Repairing ‘Broken’ Surveillance One such factor is called epithelial V-like antigen, or EVA. The EVA is active on cells located in a barrier in the brain called the blood-cerebrospinal fluid barrier. EVA interacts with T lymphocytes, a type of white blood cell. During normal immune surveillance, T lymphocytes move through the barrier and destroy foreign cells. But in MS, T lymphocytes attack the myelin coating on nerves.