Objective: Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) is a disabling illness, characterized by persistent, debilitating fatigue and a multitude of symptoms. Immunological alterations are prominent in CFS/ME cases, however little is known about the relationship between CFS/ME severity and the extent of immunological dysfunction. The purpose of this study was to assess innate and adaptive immune cell phenotypes and function of two groups of CFS/ME patients, bedridden (severe) and mobile (moderate).
Methods: CFS/ME participants were defined using the Centres for Disease Prevention and Control (1994 CDC) Criteria for CFS/ME.
Participants were grouped into healthy controls (n=22, age=40.14 Â± 2.38), moderate/mobile (n=23; age=42.52 Â± 2.63) and severe/bedridden (n=18; age=39.56 Â± 1.51) CFS/ME patients. Flow cytometric protocols were used to examine neutrophil, monocyte, dendritic cells (DCs), iNKT, Treg, B, gamma delta and CD8+ T cell phenotypes, NK cytotoxic activity and receptors.
Results: The present data found that CFS/ME patients demonstrated significant decreases in NK cytotoxic activity, transitional and regulatory B cells, gamma delta 1T cells, KIR2DL1/DS1, CD94+ and KIR2DL2/L3.
Significant increases in CD56-CD16+NKs, CD56dimCD16- and CD56brightCD16-/dim NKs, DCs, iNKT phenotypes, memory and naive B cells were also shown in CFS/ME participants. Severe CFS/ME patients demonstrated increased CD14-CD16+ DCs, memory and naÃ¯ve B cells, total iNKT, iNKT cell and NK phenotypes compared to moderate CFS/ME patients.
Conclusion: This study is the first to determine alterations in NK, iNKT, B, DC and gamma delta T cell phenotypes in both moderate and severe CFS/ME patients. Immunological alterations are present in innate and adaptive immune cells and sometimes, immune deregulation appears worse in CFS/ME patients with more severe symptoms. It may be appropriate for CFS/ME patient severity subgroups to be distinguished in both clinical and research settings to extricate further immunological pathologies that may not have been previously reported.
Analysis of the relationship between immune dysfunction and symptom severity in patients with CFS/ME, by Sharni Lee Hardcastle et al in J Clin Cell Immunol 5: 190.