Raised levels of plasma interleukin-1beta in major and postviral depression.

Interleukin-1beta (IL-1beta) is released as part of the acute phase immune response and can directly stimulate the release of corticotrophin-releasing hormone and thus induce hypothalamic pituitary adrenal axis hyperactivity. Major depression has been shown to be accompanied by both an acute phase immune response, including raised IL-1beta production and hypothalamic pituitary adrenal axis hyperactivity. In this study the possible role of IL-1beta in major depression and postviral depression was investigated. Plasma IL-1beta levels were measured in four groups; patients suffering from postviral depression (n= 17), patients with major depression (n = 20), subjects who were postviral and euthymic (n= 12) and normal controls (n = 20). IL-1beta serum concentrations were significantly elevated in both groups of depressed patients compared to controls. The serum concentrations of IL-1beta were higher in the postviral group than in the major depression group; this difference was not significant. These data confirm previous suggestions of elevated IL-1beta levels in major depression and postviral depression. IL-1beta is known to induce depressive symptoms as well as sickness behaviour and may contribute to the hypothalamic pituitary adrenal axis hyperactivity found in mood disorders.