Acute hepatitis A (AHA) involves severe CD8 T cell-mediated liver injury. Here we showed during AHA, CD8 T cells specific to unrelated viruses became activated. Hepatitis A virus (HAV)-infected cells produced IL-15 that induced T cell receptor (TCR)-independent activation of memory CD8 T cells. TCR-independent activation of non-HAV-specific CD8 T cells were detected in patients, as indicated by NKG2D upregulation, a marker of TCR-independent T cell activation by IL-15. CD8 T cells derived from AHA patients exerted innate-like cytotoxicity triggered by activating receptors NKG2D and NKp30 without TCR engagement. We demonstrated that the severity of liver injury in AHA patients correlated with the activation of HAV-unrelated virus-specific CD8 T cells and the innate-like cytolytic activity of CD8 T cells, but not the activation of HAV-specific T cells. Thus, host injury in AHA is associated with innate-like cytotoxicity of bystander-activated CD8 T cells, a result with implications for acute viral diseases.

The intent of this study was to explore bystanders' personal and situational variables predicting their behavioural reactions to school bullying by investigating a sample of 298 college students who had witnessed bullying during middle or high school. Results indicated that the bystander personal variables, gender and past experience as a bully or bully-victim, significantly predicted their reactions to bullying. All three types of bullying (physical, verbal and social), plus bystander relationship with bully or victim were identified as significant situational predictors of bystander behaviour.

No abstract

The Impact of Event Scale—Revised (D. S. Weiss &C. R. Marmar, 1997) was used to obtain self‐reported trauma levels from 587 young adults recalling childhood or adolescence experiences as witnesses to common forms of repetitive abuse defined as bullying. Mean participant scores were in a range suggesting potential need for clinical assessment at the time these events occurred. Multiple regression analysis identified significant predictors of distress levels, with intensity of abuse being the strongest. Additional results and implications of findings are discussed.