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Objective: It is assumed that stress-related changes in the endocrine and immune systems are key mediators involved in the development of diseases associated with posttraumatic stress disorder (PTSD). Evidence suggests that those changes might be related to the duration of PTSD. The aim of our study was to investigate the differences in selected endocrine- and immune-related variables between PTSD patients and control subjects, and whether these differences persist over time. Methods: We assessed 39 Croatian war veterans with PTSD and 25 healthy volunteers (civilians without traumatic experience), all men, at two time points separated by 5.6 years (median; interquartile range: 5.4–6.3). Cortisol and prolactin levels were measured by radioimmunoassays while interleukin-6 and tumor necrosis factor-α were determined by enzyme-linked immunosorbent assays. Immune function was assessed by in vitro natural killer cell cytotoxicity (NKCC). Lymphocyte counts, immunophenotype and intracellular glucocorticoid receptor expression in various lymphocyte subsets were determined by three-color flow cytometry. Results: At the first assessment, moderate to large effect size estimates of differences between patients and controls were observed for most of the measured variables. Only prolactin levels and lymphocyte counts remained significantly elevated in PTSD patients at the second assessment with low to moderate effect size estimates of differences between patients and controls in other variables. Conclusion: Observed endocrine- and immune-related changes in PTSD over time may depend on the duration of the allostatic load posed by the disorder and its impact on interactions between the endocrine and immune systems involved in stress response.

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BackgroundRegulatory T cells (Tregs) play a key role in immune homeostasis in vivo. Tregs have a critical role in preventing the development of autoimmune diseases and defects in Treg function are implicated in various autoimmune disorders. Individuals with posttraumatic stress disorder (PTSD) have higher prevalence of autoimmune disorders than the general population. We hypothesized that war veterans with PTSD would exhibit a decreased number and/or altered phenotype of Tregs.MethodsWe analyzed peripheral blood mononuclear cells (PBMCs) of patients with PTSD (N = 21) (mean age = 45.9) and age-matched healthy controls (N = 23) (mean age = 45.7) to determine the proportion of Tregs and their phenotype according to the expression of CD127 and HLA-DR markers which describe the differentiation stages of Tregs. In addition, we analyzed the expression of membrane ectoenzyme CD39 on Tregs of the study groups, an important component of the suppressive machinery of Tregs.ResultsWe found no differences in the proportion of Tregs between PTSD patients and controls, but PTSD patients had a higher percentage of CD127-HLA-DR- Tregs and a lower percentage of CD127loHLA-DR+ Tregs compared to controls. There was no difference in expression of CD39 on Tregs of the study groups.ConclusionsAlthough the proportions of Tregs in PTSD patients were unchanged, we found that they exhibit a different phenotype of Tregs that might be less suppressive. Impaired differentiation and function of Tregs is likely involved in disruption of immune homeostasis in PTSD.

A number of peripheral blood analytes have been proposed as potential biomarkers of post-traumatic stress disorder (PTSD). Few studies have investigated whether observed changes in biomarkers persist over time. The aim of this study was to investigate the association of combat-related chronic PTSD with a wide array of putative PTSD biomarkers and to determine reliability of the measurements, i.e., correlations over time. Croatian combat veterans with chronic PTSD (n = 69) and age-matched healthy controls (n = 32), all men, were assessed at two time points separated by 3 months. Serum levels of lipids, cortisol, dehydroepiandrosterone-sulfate (DHEA-S), prolactin, and C-reactive protein were determined. Multiplex assay was used for the simultaneous assessment of 13 analytes in sera: cytokines [interferon-γ, interleukin (IL)-1β, IL-2, IL-4, IL-6, TNF-α], adhesion molecules (sPECAM-1, sICAM-1), chemokines (IL-8 and MIP-1α), sCD40L, nerve growth factor, and leptin. Group differences and changes over time were tested by parametric or non-parametric tests, including repeated measures analysis of covariance. Reliability estimates [intraclass correlation coefficient (ICC) and kappa] were also calculated. Robust associations of PTSD with higher levels of DHEA-S [F(1,75) = 8.14, p = 0.006)] and lower levels of prolactin [F(1,75) = 5.40, p = 0.023] were found. Measurements showed good to excellent reproducibility (DHEA-S, ICC = 0.50; prolactin, ICC = 0.79). Serum lipids did not differ between groups but significant increase of LDL-C after 3 months was observed in the PTSD group (t = 6.87, p < 0.001). IL-8 was lower in the PTSD group (t = 4.37, p < 0.001) but assessments showed poor reproducibility (ICC = −0.08). Stable DHEA-S and prolactin changes highlight their potential to be reliable markers of PTSD. Change in lipid profiles after 3 months suggests that PTSD patients may be more prone to hyperlipidemia. High intra-individual variability in some variables emphasizes the importance of longitudinal studies in investigations of PTSD biomarkers.