Associations of number and severity of depressive episodes with C-reactive protein and Interleukin-6

Severity of depression is correlated with elevated CRP but not with IL-6. No association found between number of depressive episodes and levels of CRP and IL-6. It is possible that immune dysregulation is not generally present in depression, but might be restricted to particular subgroups of depressed patients. Several factors that could influence the depression and inflammation relationship need further investigation.