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

Objective: Interleukin-1 beta (IL-1 beta) 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-1 beta production and hypothalamic-pituitary-adrenal axis hyperactivity. In this study the possible role of IL-1 beta in major depression and postviral depression was investigated. Method: Plasma IL-1 beta 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). Results: IL-1 beta serum concentrations were significantly elevated in both groups of depressed patients compared to controls. The serum concentrations of IL-1 beta were higher in the postviral group than in the major depression group; this difference was not significant. Conclusion: These data confirm previous suggestions of elevated IL-1 beta levels in major depression and postviral depression. IL-1 beta 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.