Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) and Multiple Sclerosis (MS) patients suffer from debilitating fatigue which is not alleviated by rest. In addition to the fatigue related symptoms suffered by CFS/ME and MS patients, dysfunction of the immune system and in particular, reduced Natural Killer (NK) cell cytotoxic activity has also been reported in CFS/ME and MS.
The purpose of this pilot study was to compare NK cellular mechanisms in CFS/ME and MS patients to investigate potential dysfunctions in the NK cell activity pathway. Flow cytometry protocols assessed CD56dim CD16+ and CD56bright CD16+/- NK cell expression of adhesion molecules, NK activating and inhibiting receptors, NK cell maturation and lytic proteins.
All participants in this study were female and included 14 CFS/ME patients, 9 MS patients and 19 non-fatigued controls. The patient groups and the non-fatigued controls were not taking any immunosuppressive or immune enhancing medications.
In the MS cohort, KIR2DL5 was significantly increased on CD56bright CD16+/- NK cells and expression of CD94 was significantly increased on CD56dim CD16+ NK cells in comparison to the controls. Co-expression of CD57 and perforin was significantly increased on CD56dim CD16+ NK cells from CFS/ME patients compared to the MS and non-fatigued control participants.
The results from this pilot study suggest that NK cells from CFS/ME and MS patients may have undergone increased differentiation in response to external stimuli which may affect different mechanisms in the NK cell cytotoxic activity pathway.
Pilot Study of Natural Killer Cells in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Multiple Sclerosis, by TK Huth, EW Brenu , S Ramos, T Nguyen, S Broadley, D Staines, S Marshall-Gradisnik in Scand J Immunol. 2015 Sep 18. [Epub ahead of print]