Aberrant interleukin-2, receptor-mediated blastoformation of peripheral blood lymphocytes in a severe major depressive episode

Background. We examined interleukin-2 (IL-2) related immune pathways in depression to elucidate mechanisms underlying various immunological disturbances associated with depression. Methods. Subjects comprised 35 unmedicated patients with a major depressive episode without psychotic features and 36 age- and sex-matched healthy volunteers. The immune parameters examined included the numbers of B and T cells, IL-2 receptor-mediated blastoformation (IL-2R-mediated blastoformation), IL-2 production and expression of the IL-2 receptor α-subunit. Results. The patients with a severe episode showed significantly lower IL-2R-mediated blastoformation than the controls. There was a statistically significant negative correlation between IL-2R-mediated blastoformation and the severity of depression at the time of entry. Conclusion. The reduced IL-2R-mediated blastoformation may partly explain several previously reported abnormal immune functions associated with depression.