Immunogenetics of posttraumatic stress disorder (PTSD) in women veterans

Posttraumatic stress disorder (PTSD) is a debilitating psychiatric condition that is associated with concomitant immune system dysfunction. Here we evaluated the influence of genes involved in the human immune response, Human Leukocyte Antigen (HLA), on lifetime PTSD in primarily Caucasian women veterans. High-resolution HLA genotyping was completed for 372 participants. We assessed differences in HLA makeup between Control (n = 277) and lifetime PTSD (n = 95) groups. HLA was found to have a significant overall effect on lifetime PTSD occurrence (P < 0.00001). Of the 192 alleles identified in this sample, the frequencies of 15 alleles significantly differed between groups. Two alleles - HLA-A*02:01 and DPB1*04:01 -occurred more frequently in controls, presumably indicating protective effects. Thirteen alleles (6 Class I, 7 Class II) occurred more frequently in the lifetime PTSD group, presumably indicating susceptibility effects. In analysis evaluating the effect of the combined presence in individual participants of a protective allele and a susceptibility allele, the presence of a protective allele neutralized the effect of the susceptibility alleles. These findings, which add to the nascent literature on immunogenetics of PTSD, are discussed in terms of the evolutionary role of HLA in host protection against foreign antigens.