Suppression of cellular immunity in men with a past history of posttraumatic stress disorder

Objective: High rates of medical morbidity have been reported in subjects w ith posttraumatic stress disorder (PTSD). The authors examined immune funct ion in subjects in remission from past PTSD. Method: The initial study group was composed of 1,550 Japanese male workers . Japanese versions of the Events Check List, the Impact of Event Scale-Rev ised, and the Diagnostic Interview Schedule for DSM-IV were used to identif y subjects who had a past history of PTSD. Twelve of the workers were ident ified as having such a history. These men were matched in age and smoking h abits, which affect immunity, to 48 comparison subjects who had similar str essful life experiences but no current or past history of PTSD. Natural kil ler (NK) cell activity, lymphocyte subset counts, and production of interfe ron gamma (lFN-gamma) and interleukin-4 (IL-4) were measured in the 60 men by means of phytohemagglutinin stimulation. Results: The number of lymphocytes, number of T cells, NK cell activity, an d total amounts of IFN-gamma and IL-4 were significantly lower in the 12 me n with a past history of PTSD. Conclusions: PTSD leaves a long-lasting immunosuppression and has long-term implications for health.