A Pilot Investigation of Natural Killer Cell Function and Phenotypes in Stable and Active Multiple Sclerosis Patients

Abstract

Background: Previous studies have reported impaired cytotoxic activity in Natural Killer (NK) CD56Dim and CD56Bright cell phenotypes in peripheral blood associated with Multiple Sclerosis (MS). Recently it has been suggested that NK cell phenotype could be associated with new lesions on Magnetic resonance imaging (MRI) and may be used as an immunological indicator of disease activity. This project, for the first time, investigates NK cell cytotoxicity in MS patients with active and stable lesions. Methods: NK cell cytotoxic activity and NK CD56Dim and CD56Bright cell phenotypes were examined in MS patients using flow cytometry. Isolated NK cells were labelled with antibodies to determine CD56Dim and CD56Bright NK cells and cytotoxic function using target cells (K562). Seven patients (aged 38.0 ± 3.21) with stable Relapsing Remitting MS (RRMS) who had previously received alemtuzumab (Lemtrada®), five patients with active MS (aged 32.66 ± 5.17) on nil medication and five healthy controls (aged 34.4 ± 6.12) participated. Results: There were no significant differences for NK cell cytotoxic activity and NK CD56Dim and CD56Bright phenotypes between stable RRMS, active RRMS and healthy controls. Conclusion: Clear associations between NK cell cytotoxicity and clinical MS subtypes in this study were not identified.