The observation in PTSD of lower relative expression of TNFRSF14 concurrently with TSPO, may reflect a reduction of microglia that are responsive to pro-inflammatiory TNF-α signaling and, in fact, parallels the association, though non-significant, of lower TSPO availability with lower peripheral TNF-α levels in our PET study. The gene discussed is TNF; the disease is post-traumatic stress disorder.