Carmen S, Valles-Colomer M, Arolt V, et al. - Since prior investigation has shown a strong association between immune system abnormalities and Major Depressive Disorder (MDD), researchers examined the connection between circulating immune cell composition and suicidal risk status in this study including a large and well-matched cohort comprising 153 patients who received a diagnosis of MDD and 153 age and gender matched controls. Among participants, the evaluation of percentages of circulating peripheral blood mononuclear cells with emphasis on T helper cell subsets (memory T helper cells, Th1, Th2, Th17 and T regulatory cells) was done. Findings revealed higher abundance of memory T helper cells, this is suggestive of premature aging of the immune system in MDD patients, even during young adulthood. The highest memory T helper cells was detected in patients carrying a high risk for suicide, and these patients also displayed a robust increase of Th17 cells vs other suicide risk groups. The clearest immune abnormalities were evident in patients at high risk for suicide, and these patients may signify a clinically relevant subtype of depression.