Research

Plasma cytokines in women with chronic fatigue syndrome

Mary Ann Fletcher^1,2* , Xiao Rong Zeng^1,2 , Zachary Barnes¹ , Silvina Levis^1,2 and Nancy G Klimas^1,2*

¹  Department of Medicine, University of Miami Miller School of Medicine, 1600 NW 10th Ave, Miami, FL USA

²  Miami Veterans Health Care Center, 1201 NW 16th St, Miami, FL USA

author email corresponding author email* Contributed equally

Journal of Translational Medicine 2009, 7:96doi:10.1186/1479-5876-7-96

Published:	12 November 2009

Abstract

Background

Chronic Fatigue Syndrome (CFS) studies from our laboratory and others have described cytokine abnormalities. Other studies reported no difference between CFS and controls. However, methodologies varied widely and few studies measured more than 4 or 5 cytokines. Multiplex technology permits the determination of cytokines for a large panel of cytokines simultaneously with high sensitivity and with only 30 ul of plasma per sample. No widely accepted laboratory test or marker is available for the diagnosis or prognosis of CFS. This study screened plasma factors to identify circulating biomarkers associated with CFS.

Methods

Cytokines were measured in plasma from female CFS cases and female healthy controls. Multiplex technology provided profiles of 16 plasma factors including the pro -inflammatory cytokines: tumor necrosis factor α (TNFα), lymphotoxin α (LTα), interleukin (IL) - IL-Iα, IL-1β, IL-6; T_H1 cytokines: interferon γ (IFNγ), IL-12p70, IL-2, IL-15; T_H2: IL-4, IL-5; T_H17 cytokines, IL-17 and IL-23; anti-inflammatory cytokines IL-10, IL-13; the inflammatory mediator and neutrophil attracting chemokine IL-8 (CXCL8). Analysis by receiver operating characteristic (ROC) curve assessed the biomarker potential of each cytokine.

Results

The following cytokines were elevated in CFS compared to controls: LTα, IL-1α, IL-1β, IL-4, IL-5, IL-6 and IL-12. The following cytokines were decreased in CFS: IL-8, IL-13 and IL-15. The following cytokines were not different: TNFα, IFNγ, IL-2, IL-10, IL-23 and IL-17. Applying (ROC) curve analyses, areas under the curves (AUC) for IL-5 (0. 84), LTα (0.77), IL-4 (0.77), IL-12 (0.76) indicated good biomarker potential. The AUC of IL-6 (0.73), IL-15 (0.73), IL-8 (0.69), IL-13 (0.68) IL-1α (0.62), IL-1β (0.62) showed fair potential as biomarkers.

Conclusion

Cytokine abnormalities are common in CFS. In this study, 10 of 16 cytokines examined showed good to fair promise as biomarkers. However, the cytokine changes observed are likely to more indicative of immune activation and inflammation, rather than specific for CFS. As such, they are targets for herapeutic strategies. Newer techniques allow evaluation of large panels of cytokines in a cost effective fashion.