Immune Abnormalities Meet Diagnostic Criteria for Myalgic Encephalomyelitis

Immunological abnormalities have been identified in Myalgic Encephalomyelitis, also known as Chronic Fatigue Syndrome (ME/CFS) patients and significant developments have been made to the diagnostic criteria

Potential immunological markers have not been assessed in patients fulfilling these latest clinical requirements and therefore there is a need to evaluate immunological parameters in patients that also fulfill the latest diagnostic criteria available known as the International Consensus Criteria (ICC).

Immunologists at Griffith University (Gold Coast, Australia) recruited 63 participants of which 41 were ME/CFS patients and 22 were healthy controls. Whole blood samples were collected from all participants. With the exception of Natural Killer (NK) cell phenotyping experiments, whole blood was used for all phenotyping studies.

For all flow cytometer experiments, the monoclonal antibodies were fluorescently labeled with fluorescein isothiocyanate, phycoerythrin, allophycocyanin and peridinin chlorophyll, and analysis was performed on a four-color flow cytometer. The activity of NK cells was measured using a well-known flow cytometric method stained with annexin V and 7-AAD (Becton Dickinson (BD); San Diego, CA, USA) and analyzed on the BD fluorescence-activated cell sorting (FACS) Calibur flow cytometer.

In patients with ME/CFS, NK cell activity was significantly reduced in comparison to healthy controls. Measures of NK cell lytic proteins did not yield any significance difference between the groups. A significant increase in regulatory T-cells (Tregs) was observed ME/CFS patients in comparison to healthy controls. A significant decrease in cluster of differentiation CD39+ Tregs was observed in one group of ME/CFS patients in comparison to healthy controls. No significant differences were observed in B-cells, NK cells and plasmacytoid and myeloid (DC) phenotypes.

The authors concluded that differences could be found in human neutrophil antigens and expression of natural killer cell receptors between patient groups. Highly significant correlations were also found between physical status and some immune parameters in ICC defined patients. This preliminary investigation on different diagnostic criteria suggests that the ICC may be more effective in detecting salient differences in the immune system. The study was published on November 14, 2013, in the Journal of Molecular Biomarkers & Diagnosis.

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