Disturbance of Serum Interleukin-2 and Interleukin-8 Levels in Posttraumatic and Non-Posttraumatic Stress Disorder Earthquake Survivors in Northern China

Abstract

Objective: It is evident that immune cytokines are involved in the pathophysiology of posttraumatic stress disorder (PTSD), but results of different studies are still inconsistent. Here, serum interleukin (IL)-2, IL-6 and IL-8 levels were compared between earthquake survivors with PTSD, those with non-PTSD and normal controls to investigate whether there is any relationship between cytokine levels and PTSD. In addition, the relationship of these cytokines with psychological parameters of the disorder was examined as well. Methods: Thirty-four earthquake survivors with PTSD (according to DSM-IV criteria), 30 earthquake survivors with non-PTSD and 34 controls were recruited in northern China using the Composite International Diagnostic Interview instrument. Serum IL-2, IL-6 and IL-8 levels were compared. IL-2 levels were measured by radioimmunometric assay, while serum IL-6 and IL-8 levels were measured using sandwich enzyme-linked immunosorbent assay. Psychological symptoms were assessed using 3 subscales of the Symptoms Checklist (SCL-90-R), including depression, anxiety and somatization. Results: Only earthquake survivors diagnosed with PTSD had significantly lower serum IL-8 levels. Also, we found that earthquake survivors (either with PTSD or non-PTSD) had significantly lower serum IL-2 levels and more severe psychological symptoms. The severity of depressive and anxiety symptoms in earthquake survivors was positively related to serum IL-6 levels. Conclusions: PTSD may be associated with a reduced level of serum IL-8, and traumatic survivors may be associated with a lower level of serum IL-2.