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Background: Chronic fatiguing illness remains a poorly understood syndrome of unknown pathogenesis. We attempted to identify biomarkers for chronic fatiguing illness using microarrays to query the transcriptome in peripheral blood leukocytes.
Methods: Cases were 44 individuals who were clinically evaluated and found to meet standard international criteria for chronic fatigue syndrome or idiopathic chronic fatigue, and controls were their monozygotic co-twins who were clinically evaluated and never had even one month of impairing fatigue.
Biological sampling conditions were standardized and RNA stabilizing media were used. These methodological features provide rigorous control for bias resulting from case-control mismatched ancestry and experimental error.
Individual gene expression profiles were assessed using Affymetrix Human Genome U133 Plus 2.0 arrays.
Findings: There were no significant differences in gene expression for any transcript.
Conclusions: Contrary to our expectations, we were unable to identify a biomarker for chronic fatiguing illness in the transcriptome of peripheral blood leukocytes suggesting that positive findings in prior studies may have resulted from experimental bias.
Source: PLoS ONE, Jun 5, 2009;4(6):e5805. PMID:19503787, by Byrnes A, Jacks A, Dahlman-Wright K, Evengard B, Wright FA, Pedersen NL, Sullivan PF. Departments of Genetics and Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Departments of Medical Epidemiology and Biostatistics, Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Microbiology, University of Umea, Sweden.