CD8+T cells in CMV seropositive and seronegative MDD patients and HC: Staining C data shows that the exaggerated increase of CD8+ cytotoxic T cells in CMV-antibody positive MDD patients (as illustrated in Fig. 1) was mainly due to a statistically significant increase in memory cells (although naïve cells were also increased, be it not significantly; Table 3). Here, CD8A is linked to major depressive disorder.