CD4 and post-traumatic stress disorder: We reported previously that in PTSD patients, there is significant increase in peripheral blood mononuclear cells (PBMCs), the number of CD4+, CD8+, NK and B cells in PBMC, and production of pro-inflammatory cytokines such as IFNγ, IL-17, RANTES and IL-12 (Zhou et al. 2014; Bam et al. 2016a).