Lipopolysaccharide-induced cytokine production in obsessive-compulsive disorder and generalized social anxiety disorder

The immune system is implicated in the pathophysiology of various psychiatric disorders. In anxiety disorders such as obsessive-compulsive disorder (OCD) and generalized social anxiety disorder (GSAD), immunological findings are equivocal and sparse. In this study, we investigated the lipopolysaccharide (LPS)- stimulated cytokine levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-8 (IL-8) by peripheral blood leukocytes in 26 OCD patients, 26 GSAD patients, and 52 healthy controls. We found that leukocytes of OCD patients produced less IL-6 compared with matched controls, whereas no cytokine differences were found between GSAD patients and matched controls. When both patient groups were compared, a trend toward lower IL-6 levels in OCD patients was observed. This supports the idea of immunological involvement in the pathophysiology of OCD and suggests that GSAD and OCD might be different in immunological respect