Decreased blood levels of tumor necrosis factor-alpha in patients with obsessive-compulsive disorder

To investigate immune system function in obsessive-compulsive disorder (OCD) we measured plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) in 14 drug-free obsessive-compulsive patients and 14 matched healthy controls. No significant differences were observed between patients and controls in plasma levels of IL-1 beta and IL-6, whereas plasma levels of TNF-alpha were significantly lower (p = 0.001) in the former. Blood levels of prolactin did not differ between the two groups, whereas plasma cortisol concentrations were significantly higher in patients than in healthy subjects (p = 0.02). No significant correlation was found between immune parameters, on the one hand, and endocrine or psychopathological measures on the other. These results suggest that OCD is associated with a decreased production in TNF-alpha, but normal synthesis of IL-1 beta and IL-6.