AHMF: 98 Conference: McGregor

Classification of CFS Patients by Assessing Plasma Lipid Homeostasis

Neil R. McGregor, R. Hugh Dunstan [1], Timothy K. Roberts [1], Mark Donohoe [2], Jennifer A. Watkins [1], Henry L. Butt [3], Raymond N. Murdoch [1].

Collaborative Pain Research Unit
Neurobiology Research Unit
University of Sydney
Westmead Hospital
Westmead
NSW 2084, Australia
1 Bioanalytical Research Group
The University of Newcastle
Callaghan
NSW 2308, Australia.
2 Environmental Medical Centre
Mosman
NSW 2088, Australia.
3 Division of Microbiology and Infectious Diseases
Hunter Area Pathology Service
Newcastle, NSW 2308, Australia.

A study was undertaken in 60 chronic fatigue syndrome (CFS) patients and 39 age and sex-matched non-CFS control subjects. Plasma saponified lipid products were assessed using capillary gas chromatography - mass spectrometry (GC-MS) to measure qualitative changes in plasma lipid profiles. Previous analyses of these data indicated that the CFS patients had significantly different plasma lipid profiles compared with the controls. This study utilised clustering techniques to determine whether patients could be classified into subgroups on the basis of similarities of lipid profile characteristics.

Five separate subgroups were characterised in this CFS study cohort, which had significantly different lipid, age and sex characteristics, but were independent of the type of onset (sudden, gradual). In contrast, 34 of the 39 control subjects (87%) had a homogeneous set of lipid profiles which was designated the "control profile".

The characteristics assessed in the 5 CFS profiles were suggestive of anomalies in cholesterol, saturated fatty acid and n-6 fatty acid homeostasis, as well as b-oxidation of fatty acids. This study demonstrates a high degree of heterogeneity in the lipid homeostasis of patients who comply with the CFS definition. The differences in lipid homeostasis may have arisen from combinations of underlying genetic, dietary, immunological, environmental or pathogen altered responses. The lipid profiles can therefore be used to classify patients with similar lipid characteristics to give relatively homogeneous sets of patients for investigation. Individual patients could be aligned with the lipid profiles from our CFS research to assign their altered homeostasis to a particular CFS type.

These data suggest that the current CDC clinical definition of CFS falls well short of producing homogenous sets of patients and should be reviewed to include biochemical data which aligns patients with specific anomalies in cholesterol and fatty acid metabolism.