From Psychotherapy and Psychosomatics, published online 20 July 2012 (full article behind a paywall).
Inflammatory and Cell-Mediated Immune Biomarkers in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Depression: Inflammatory Markers Are Higher in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome than in Depression
Michael Maes(a), Frank N.M.Twisk(b), Karl Ringel(c)
(a) Maes Clinics, TRIA, Bangkok, Thailand;
(b) ME-de-patiënten Foundation, Limmen, The Netherlands;
(c) Immunologische Laboratorien, Aachen, Germany
BACKGROUND: Background: Depression is an inflammatory disorder while many authors declare myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) to be a functional disorder. The aim of the present study is to compare inflammatory and cell-mediated immune (CMI) responses between depression and ME/CFS.
METHODS: We measured two proinflammatory cytokines (PICs) in plasma, interleukin-1 (IL-1) and tumour necrosis factor-α (TNF-α), with enzyme-linked immunosorbent assays, and serum neopterin with a radioimmunoassay in controls, ME/CFS and depressive
RESULTS: Plasma PICs were significantly higher in ME/CFS than in depression and higher in both patient groups than in controls. Increased PIC levels in depression were attributable to the presence of fatigue and physio-somatic symptoms. Serum neopterin did not differ significantly between depression and ME/CFS but was higher in both patient groups than in controls.
The significant positive correlations between neopterin and either IL-1 or TNF-α were significantly greater in depression than in ME/CFS.
CONCLUSIONS: Since PICs cause depression-like behaviors and fatigue/malaise, we suggest that inflammation may play a role in the pathophysiology of ME/CFS and depression. Increased neopterin also seems to contribute to thepathophysiology of both disorders.
This study has detected a shared‘pathway phenotype’, i.e. disorders in inflammatory and CMI pathways, which underpins both ME/CFS and depression and, therefore, may explain the co-occurrence of both disorders. ME/CFS and depression are discriminated from each other by increased PICs in ME/CFS and differences in the immune cell communication networks.