Posttraumatic stress disorder (PTSD) is associated with increased medical morbidity, particularly from the autoimmune and cardiovascular diseases. Changes in the endocrine and immune system are key mediators in this process. The aim of our study was to investigate weather hormones (cortisol and prolactin), proinflammatory cytokines (interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α)), components of HPA-axis (lymphocyte expression of glucocorticoid receptor (GR)), immune function (natural killer cell cytotoxicity) and peripheral blood percentages of various lymphocyte subpopulations (T cells, helper T cells, cytotoxic T cells, B cells and natural killer cells) change in patients with posttraumatic stress disorder over time.