BackgroundPosttraumatic stress disorder (PTSD) is associated with an enhanced risk for cardiovascular and other inflammatory diseases. Chronic low-level inflammation has been suggested as a potential mechanism linking these conditions.MethodsWe investigated plasma cytokine levels as well as spontaneous and lipopolysaccharide (LPS)-stimulated cytokine production by peripheral blood mononuclear cells (PBMCs) in a group of 35 severely traumatized PTSD patients compared to 25 healthy controls.ResultsSpontaneous production of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α by isolated PBMCs was significantly higher in the PTSD compared to the control group and even correlated with PTSD symptom severity within the PTSD group. In contrast, circulating plasma levels of pro- and anti-inflammatory cytokines such as IL-6, IL-8, IL-10, TNF-α, or monocyte chemotactic protein (MCP)-1 were not significantly altered in PTSD patients compared to healthy controls.ConclusionsOur findings indicate that PBMCs of PTSD patients are already pre-activated in vivo, providing further evidence for low-grade inflammation in PTSD. This might possibly represent one psychobiological pathway from PTSD to poor physical health.

Posttraumatic stress disorder (PTSD) is associated with an enhanced susceptibility to various somatic diseases. However, the exact mechanisms linking traumatic stress to subsequent physical health problems have remained unclear. This study investigated peripheral T lymphocyte differentiation subsets in 19 individuals with war and torture related PTSD compared to 27 non-PTSD controls (n=14 trauma-exposed controls; n=13 non-exposed controls). Peripheral T cell subpopulations were classified by their characteristic expression of the lineage markers CD45RA and CCR7 into: naïve (CD45RA(+) CCR7(+)), central memory (T(CM): CD45RA(-) CCR7(+)) and effector memory (T(EM): CD45RA(-) CCR7(-) and T(EMRA): CD45RA(-) CCR7(-)) cells. Furthermore, we analyzed regulatory T cells (CD4(+)CD25(+)FoxP3(+)) and ex vivo proliferation responses of peripheral blood mononuclear cells after stimulation with anti-CD3 monoclonal antibody. Results show that the proportion of naïve CD8(+) T lymphocytes was reduced by 32% (p=0.01), whereas the proportions of CD3(+) central (p=0.02) and effector (p=0.01) memory T lymphocytes were significantly enhanced (+22% and +34%, respectively) in PTSD patients compared to non-PTSD individuals. To a smaller extent, this effect was also observed in trauma-exposed non-PTSD individuals, indicating a cumulative effect of traumatic stress on T cell distribution. Moreover, PTSD patients displayed a 48% reduction in the proportion of regulatory T cells (p<0.001). Functionally, these alterations were accompanied by a significantly enhanced (+34%) ex vivo proliferation of anti-CD3 stimulated T cells (p=0.05). The profoundly altered composition of the peripheral T cell compartment might cause a state of compromised immune responsiveness, which may explain why PTSD patients show an increased susceptibility to infections, and inflammatory and autoimmune diseases.

Oculodentodigital dysplasia (ODDD) is a dominantly inherited human disorder associated with different symptoms like craniofacial anomalies, syndactyly and heart dysfunction. ODDD is caused by mutations in the GJA1 gene encoding the gap junction protein connexin43 (Cx43). Here, we have characterized four Cx43 mutations (I31M, G138R, G143S and H194P) after stable expression in HeLa cells. In patients, the I31M and G138R mutations showed all phenotypic characteristics of ODDD, whereas G143S did not result in facial abnormalities and H194P mutated patients exhibited no syndactylies. In transfected HeLa cells, these mutations led to lack of the P2 phosphorylation state of the Cx43 protein, complete inhibition of gap junctional coupling measured by neurobiotin transfer and increased hemichannel activity. In addition, altered trafficking and delayed degradation were found in these mutants by immunofluorescence and pulse-chase analyses. In G138R and G143S mutants, the increased hemichannel activity correlated with an increased half-time of the Cx43 protein. However, the I31M mutated protein showed no extended half-time. Thus, the increased hemichannel activity may be directly caused by an altered conformation of the mutated channel forming protein. We hypothesize that increased hemichannel activity may aggravate the phenotypic abnormalities in ODDD patients who are deficient in Cx43 gap junction channels.

Animal tumor models and human cancer studies have provided convergent evidence that chronic psychological stress plays a decisive role in modulating anti-tumor T cell immunity. However, whether chronic stress also affects anti-cancer vaccine strategies that rely on the induction of functional tumor-specific T cells has not been investigated yet. In this study we provide direct evidence that chronic stress suppresses the therapeutic efficacy of a biodegradable poly(d,l-lactide-co-glycolide) microsphere (PLGA-MS) based cancer vaccine in a murine melanoma model. Exposure of mice to social disruption stress (SDR), a well-established model mimicking psychological chronic stress in humans, significantly impaired tumor protection in response to cancer vaccination under both prophylactic and therapeutic conditions. Vaccine failure in stressed mice correlated with significantly reduced generation of interferon-γ (IFN-γ)-producing T effectors and CTL-mediated killing. Phenotypic analysis of dendritic cells (DCs) revealed that both migratory and lymphoid-resident DCs failed to undergo full maturation upon antigen uptake. Notably, decreased DC maturation was associated with a significant impairment of peripheral DCs to migrate to draining LNs and to prime subsequent T responses in vivo. In conclusion, chronic stress represents an important factor mediating immunosuppression in cancer-vaccinated hosts by impairing DC functions and subsequent T priming. Potentially, the mechanistic insights gained in this study open new avenues in utilizing the full potential of anti-cancer vaccination strategies.