One of the first EWAS of PTSD conducted in 100 trauma-exposed civilians (23 with PTSD) from the Detroit Neighborhood Health Study (DNHS) assessed methylation and non-methylation (unmethylated) and reported the unmethylation of LTA4H, CXCL8, AQP9, TREM1, F8, CCL1, PYDC1, KLRG1, IFI35, CD1D, CD2, NLRP12, GBP1, IFI16, LST1, PTPN22, TLR1, TLR3, CMKLR1, STAP1 and SLAMF7 in individuals with PTSD diagnosis, all immune-related genes. This evidence concerns the gene TREM1 and post-traumatic stress disorder.