Approximately 50% of patients with PTSD do not respond to treatment.
Hypoactivation of the hypothalamic-pituitary-adrenal axis and the low-grade inflammatory state in patients with PTSD suggest the potential for utilizing biomarkers to predict and guide treatment. It has been previously shown that pre-treatment elevated salivary cortisol and decreased urinary cortisol predict a reduction in symptoms in patients with PTSD.
The current study extended what is known about the association between PTSD and inflammation by showing that an elevated IL-10 (an anti-inflammatory cytokine) level predicted a good response to treatment in patients with PTSD.
Seventeen women with PTD (28-58 years of age) were subjected to the Trier stress test, which induces moderate psychosocial stress. IL-6 and IL-10 levels were measured before the stress test, and after the stress test but before inpatient treatment (9 weeks of trauma-focused psychotherapy).
Patients with PTSD had lower scores on the Beck Depression Inventory II (BDI-II) after treatment than before treatment. In contrast, the before and after treatment scores on the Symptom Checklist (SCL-90-R) and Global Severity Index (GSI) were not significantly different.
The IL-6 and IL-10 levels following acute stress (and before treatment) were shown to be predictive of general symptom burden and depressive symptoms after treatment. Specifically, elevated IL-6 levels predicted a greater general symptom burden and more severe depressive symptoms after treatment, whereas elevated IL-10 levels predicted a lower symptom burden and less severe depressive symptoms.