Mitogen-stimulated cell proliferation and cytokine production in major depressive disorder patients

Background: Major depressive disorder (MDD) is related to human's immune status, and immunological indicators such as mitogen stimulated cell proliferation and cytokines may become candidate biomarkers for disease diagnosis. Methods: One hundred diagnosed major depressive disorder subjects and 100 health controls were enrolled in this study. Phytohaemagglutinin and lipopolysaccharide stimulated cell proliferations and cytokine concentrations were detected in peripheral blood mononuclear cells from both groups. The corresponding stimulated responses were conducted and confirmed in chronic unpredictable mild stress (CUMS) mice. Results: Compared to the people in control group, there were lower cell proliferations and lower TNF-alpha produced in lipopolysaccharide stimulated peripheral blood mononuclear cells in depression patients, lower IL-2 and IL-10 produced in phytohaemagglutinin stimulated peripheral blood mononuclear cells in depression patients, higher IL-6, IL-10 and lower IL-2 secretions were detected in peripheral plasma in depression patients. In CUMS mice we found lower splenocyte proliferations, lower IL-1 productions and higher IL-6 secretions in lipopolysaccharide stimulated splenocytes. It seems lipopolysaccharide stimulated cell proliferation activities were inhibited in depressive states. Conclusions: Lower lipopolysaccharide stimulated cell proliferation and phytohaemagglutinin stimulated or plasma cytokine IL-2 decreases should be potential monitoring indices in the depressive state assessment for major depressive disorder patients.