Clonotypic analysis of cerebrospinal fluid T cells during disease exacerbation and remission in a patient with multiple sclerosis

Migration of autoreactive T cells into the central nervous system (CNS) compartment is thought to be an important step in the pathogenesis of multiple sclerosis (MS). To follow the evolution of T cell repertoire in the CNS of a patient with relapsing–remitting MS, we analyzed cerebrospinal fluid (CSF) cells obtained during an acute clinical exacerbation, and subsequent disease remission after 13 months of immunomodulatory therapy. T cell receptor CDR3 region length distribution was significantly altered during the relapse, demonstrating the presence of clonally expanded T cells in the CSF. CDR3 spectratyping is a valuable approach to identify disease-associated T cells in the CNS.