Patients with depression display cytokine levels in serum and cerebrospinal fluid similar to patients with diffuse neurological symptoms without a defined diagnosis.
BACKGROUND
Several reports indicate that inflammation may play a role in depression and demonstrate enhanced systemic levels of inflammatory mediators. We hypothesized that 44 patients with a diagnosis of depression would present with a specific and different serum and cerebrospinal fluid (CSF) cytokine profile compared to 21 patients with diffuse neurological symptoms, of whom 15 had fatigue as a major symptom, but no change in emotional state.


METHODS
The diagnoses of the patients with depression were according to the International Classification of Diseases, tenth edition (F32-34 spectra). Cytokine profiles in serum and CSF were determined by multiplex analysis, including 27 cytokines, chemokines, and growth factors.


RESULTS
No differences could be found between the two groups studied regarding cytokine levels in serum or CSF except for serum interleukin (IL)-1 receptor antagonist that was lower in the depression group. There were only four high correlations (>0.4) between serum and CSF levels of the cytokines, reflecting independent synthesis and turnover in these two compartments. In the control group, fatigue was associated with increased IL-1 receptor antagonist, IL-10, granulocyte-colony stimulating factor, and interferon-γ (all P<0.01).


CONCLUSIONS
Patients with depression had a similar cytokine profile as nondepressive patients, both systemically and in CSF. Fatigue was associated with higher levels of some inflammatory markers in the control group. It is possible that the presence of fatigue in a large proportion of patients and controls could contribute to the lack of difference in cytokine levels between these two groups.
Department of Research, Innlandet Hospital Trust, Brumunddal, Norway; Department of Psychology, Faculty of Social Sciences and Technology Management, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of Public Health, Hedmark University College, Elverum, Norway.
Knut A
KA
Hestad
Norwegian Centre for Aging and Health, Vestfold Health Trust, Tønsberg, Norway.
Knut
K
Engedal
Department of Research, Innlandet Hospital Trust, Brumunddal, Norway.
Jon Elling
JE
Whist
Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway; Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway; Institute of Clinical Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway; K.G. Jebsen IRC, University of Oslo, Oslo, Norway; K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway.
Pål
P
Aukrust
Department of Research, Innlandet Hospital Trust, Brumunddal, Norway; Unit for Applied Clinical Research, Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
Per G
PG
Farup
K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway; Centre of Molecular Inflammation Research, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of Immunology, Oslo University Hospital Rikshospitalet, Oslo, Norway; Research Laboratory, Nordland Hospital, Bodø, Norway.
Tom Eirik
TE
Mollnes
Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway; Institute of Clinical Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway; K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway.
Thor
T
Ueland
CSF; chemokines; cytokines; depression; fatigue; inflammation; multiplex analysis; serum