Regulatory T cells increased while IL-1β decreased during antidepressant therapy

Background Regulatory T cells (Tregs CD4(+)CD25(hi)) are specialized in steering the immune response and cytokine release to maintain tolerance to self-antigens As cytokines such as interleukin (IL)-1 beta IL-6 and interferon (IFN)-alpha have been shown to be involved in the pathophysiology of depression and cytokine levels have been shown to change during successful antidepressant treatment we tested the involvement CD4(+)CD25(hi) Tregs in these immunological processes during antidepressant therapy Methods 16 patients suffering from a depressive episode were included into the study and treated with antidepressants according to their doctor s choice Blood samples were collected during the first week after admission and after 6 weeks of treatment Therein we determined plasma levels of IL-1 beta and measured IL-1 beta IL-6 and IFN-alpha levels in the stimulated blood by performing a whole blood assay We distinguished lymphocytes and identified CD4(+)CD25(hi) Tregs by multiparameter flow cytometry The psychopathological status was assessed using the Hamilton Depression Rating Scale (HAMD-21) Results HAMD-21 score IL-1 beta serum levels as well as LPS-stimulated IL-1 beta and IL-6 production had decreased significantly at the end of treatment In contrast the amount of CD4(+)CD25(hi) cells increased significantly from 2 74% +/- 088 (mean value +/- standard deviation) to 3 54% +/- 1 21 p = 0 007 No significant changes in virus-induced IFN-alpha production was observed Conclusions The increase in CD4(+)CD25(hi) Tregs during antidepressant therapy may be the reason for the decrease in cytokine production and the recovery from depression (C) 2010 Elsevier Ltd All rights reserved