Cytokine levels as potential biomarkers for predicting the development of posttraumatic stress symptoms in casualties of accidents

Background: Traumatic injuries are usually associated with increased secretion of pro-inflammatory cytokines, and are sometimes followed by the development of acute stress symptoms (ASS) and posttraumatic stress symptoms (PTSS). Aims: To measure serum pro-and anti-inflammatory cytokines in accident casualties and to associate it with ASS at hospitalization, and with PTSS 1 month later. Methods: Participants were 48 patients, aged 20-60, hospitalized following various orthopedic injuries including bone fractures, and 13 healthy volunteers matched for gender. At hospitalization (Time 1), 30 ml heparinized venous blood were drawn and cytokines levels in serum were assessed; participants filled out the Acute Stress Disorder Inventory (ASDI), COPE, and injury-related questionnaires. One month later (Time 2), 26 participants filled out the Posttraumatic Disorder Symptom Scale (PDS). Results: High serum levels of IL-6, IL-8, and TGF-β, and low levels of serum IL-4 and IL-10 were found in injured patients as compared with controls. When controlling for age and severity of injury in the regression analysis, higher levels of IL-6 and IL-8 and lower TGF-β were predicted by higher ASS and higher use of and emotion-focused coping. Higher PTSS scores at Time 2 were predicted by higher levels of IL-8, lower levels of TGF-β, and higher ASS measured at Time 1. Conclusions: High levels of the pro-inflammatory cytokine IL-6 and IL-8 and lower levels of the regulatory cytokine TGF-β should be further assessed as a possible risk factor or a bio-marker of PTSS in accident casualties.