Expression of tumor necrosis factor-alpha and interferon-gamma mRNA in blood cells correlates with depression scores during an acute attack in patients with multiple sclerosis.

Depression is a common problem in multiple sclerosis (MS) and affects about 50% of MS patients. Since a dysregulation of cytokine levels has been implicated in the pathogenesis of MS and alterations in cytokine serum levels have been found in depressive illness, we examined the relationship between depressive symptoms, cytokine mRNA expression levels of Th1-type and Th2-type cytokines and neurological disability among early diagnosed MS patients in a prospective study. Sixteen patients with clinically or laboratory supported MS were assessed using the Beck Depression Inventory (BDI) and the Kurtzke Expanded Disability Status Scale (EDSS). Cytokine mRNA in whole blood was serially determined by a new quantitative polymerase chain reaction (PCR) method. BDI sum scores (2,9 fold) and the expression levels of tumor necrosis factor-alpha (TNF-alpha; 4 fold), interferon-gamma (IFN-gamma; 4,6 fold) and interleukin-10 (IL-10; 6,1 fold) mRNA were increased in MS patients during an acute attack compared to age and sex matched healthy controls. We detected a significant positive correlation between TNF-alpha (r=0.55) and interferon-gamma (r=0.54) mRNA expression and the BDI sum scores during an acute attack in MS patients. At follow-up after 3-6 months, only TNF-alpha mRNA expression was correlated with BDI sum scores (r=0.62 resp. r=0.31). No correlation of the BDI sum scores with Th2-type cytokine mRNA expression for interleukin-4 (IL-4) and interleukin-10 (IL-10) or with the extent of neurological disability was observed. The possible contribution of Th1-type cytokines to the development of depression in MS is discussed.