Two separate studies from the San Francisco VA Medical Center and the University of California at San Francisco have discovered that the immune systems of men and women respond differently to post-traumatic stress disorder.

Both research teams found that the immune systems of men didn’t show any response, but the immune systems of women responded very strongly. Even though a strong immune system response does protect the body from invaders like viruses and bacteria, an over-activated response can cause inflammation, which has been shown to lead to arthritis and cardiovascular disease.

The authors of one study took blood samples from 18 women and 49 men; some had PTSD, and the ones who did not acted as controls for their gender. They used gene microarray technology to find out which genes were activated by measuring immune cells that often cross the barrier between the brain and the bloodstream.

Lead author Dr. Thomas Neylan said, “We were looking for evidence of inflammation caused by immune activation. We know that people with PTSD have higher rates of cardiovascular disease and arthritis, which are diseases associated [with] chronic inflammation. We also hoped that seeing which genes were expressed in PTSD might show us potential therapeutic approaches that we hadn’t thought of”.