Objective To investigate the expression of CD161 (KLRB1) and CCR6 on human γδ T cells in blood and cerebrospinal fluid (CSF) of patients with a clinically isolated syndrome (CIS) and multiple sclerosis (MS) in relapse.
Design Flow cytometry analysis of CD161 and CCR6 expression and intracellular cytokine staining for interleukin 17 and interferon-γ on human γδ T cells in blood and CSF samples.
Setting Department of Neurology, Klinikum rechts der Isar, Technische Universität München, a tertiary referral center.
Patients Twenty-six patients with CIS/MS in active relapse, 10 patients with other autoimmune disorders, 12 patients with neuroinfectious diseases, and 15 patients with noninflammatory neurological diseases.
Main Outcome Measures Frequencies of CD161high and CCR6+ γδ T cells in blood and CSF samples of patients with CIS/MS in relapse and control patients.
Results γδ T cells were increased in both blood and CSF of patients with CIS/MS in relapse as compared with controls with noninflammatory disease. The fraction of CD161high CCR6+ γδ T cells was significantly higher in the CSF of patients with CIS/MS in relapse than of those with systemic autoimmune disorders or controls with noninflammatory disease. The CD161high CCR6+ double-positive γδ T-cell population was further enriched in the CSF in relation to blood in patients with CIS/MS in relapse but not in patients with infectious disease or the other control groups. The CD161high CCR6+ γδ T-cell population was characterized by its capacity to produce interleukin 17.
Conclusion Interleukin 17–producing CD161high CCR6+ γδ T cells might contribute to the compartmentalized inflammatory process in the central nervous system of patients with MS.