The role of immune abnormality in depression and cardiovascular disease.

Depression and cardiovascular disease (CVD) are both highly prevalent disorders, and some evidence shows that there is a 'vicious cycle' linking major depression and CVD. There is also growing evidence that immune abnormalities underpin the common pathophysiology of both CVD and major depression. The abnormalities include the following: abnormal levels of inflammatory markers, such as interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α) and interleukin-12 (IL-12); increased acute phase proteins, such as C-reactive protein, fibrinogen and haptoglobin; and abnormal complement factors. The findings show that major depression and CVD patients have greater immune abnormalities, which may increase depressive symptoms and cardiovascular pathological changes, and that there may be a bidirectional relationship, therefore more prospective studies are needed to draw conclusions.