Evaluation of Infection-Related Hospitalizations and Drug Prescriptions Among Sepsis Survivors in Germany

Sepsis Impairs IFN-γ Production in CD8 T Cells through Changes in Local Chromatin Landscape

Sepsis is a complex condition of inflammatory and immune dysregulation, triggered by severe infection. In survivors, chronic inflammation and immune dysregulation linger, facilitating the emergence of infections. CD8 dysfunction contributes to immunosuppression in sepsis survivors. We devised an animal model that enabled us to identify and analyze CD8-intrinsic defects induced by sepsis. We adoptively transferred CD45.1 CD8 OT-I T cells into CD45.2 congenic mice and subjected them to cecal ligature and puncture, to induce abdominal sepsis. One month later, we isolated the transferred CD8 cells. Surface marker expression confirmed they had not been activated through the TCR. CD8 OT-I T cells isolated from septic (or sham-operated) mice were transferred to second recipients, which were challenged with OVA-expressing Listeria monocytogenes. We compared effector capacities between OT-I cells exposed to sepsis and control cells. Naive mice that received OT-I cells exposed to sepsis had higher bacterial burden and a shorter survival when challenged with OVA-expressing L. monocytogenes. OT-I cells isolated from septic mice produced less IFN-γ but had conserved activation, expansion potential, and cytotoxic function. We observed lower transcript levels of IFN-γ and of the long noncoding RNA Ifng-as1, a local regulator of the epigenetic landscape, in cells exposed to sepsis. Accordingly, local abundance of a histone modification characteristic of active promoter regions was reduced in sepsis-exposed CD8 T cells. Our results identify a mechanism through which inflammation in the context of sepsis affects CD8 T cell function intrinsically.

Understanding health care pathways of patients with sepsis: protocol of a mixed-methods analysis of health care utilization, experiences, and needs of patients with and after sepsis

BACKGROUND

Sepsis is associated with about 20% of deaths worldwide. It often presents with non-specific initial symptoms, making its emergency treatment an interdisciplinary and cross-sectoral challenge. Three in four sepsis survivors suffers from new cognitive, psychological, or physical sequelae for which specific treatment concepts are scarce. The AVENIR project aims to improve the understanding of patient pathways, and subjective care experiences and needs along the entire healthcare pathway before, with and after sepsis. Based on this, concrete recommendations for the organization of care and patient information materials will be developed with close patient participation.

METHODS

Mixed-methods study including (1) analysis of anonymized nationwide health claims data from Germany, (2) linkage of health claims data with patient care reports (PCR) of emergency medical services from study regions in two federal states within Germany, and (3) qualitative exploration of the patient, relative, and care provider perspective on sepsis care. In (1), we analyze inpatient and outpatient health care utilization until 30 days pre-sepsis; clinical sepsis care including intra- and inter-hospital transfers; and rehabilitation, inpatient and outpatient aftercare of sepsis survivors as well as costs for health care utilization until 24 months post-sepsis. We attempt to identify survivor classes with similar health care utilization by Latent Class Analyses. In (2), PCR are linked with health claims data to establish a comprehensive database outlining care pathways for sepsis patients from pre-hospital to follow-up. We investigate e.g., whether correct initial assessment is associated with acute (e.g., same-day lethality) and long-term (e.g., new need for care, long-term mortality) outcomes of patients. We compare the performance of sepsis-specific screening tools such as qSOFA, NEWS-2 or PRESEP in the pre-clinical setting. In (3), semi-structured interviews as well as synchronous and asynchronous online focus groups are conducted and analyzed using qualitative content analyses techniques.

DISCUSSION

The results of the AVENIR study will contribute to a deeper understanding of sepsis care pathways in Germany. They may serve as a base for improvements and innovations in sepsis care, that in the long-term can contribute to reduce the personal, medical, and societal burden of sepsis and its sepsis sequelae.

TRIAL REGISTRATION

Registered at German Clinical Trial Register (ID: DRKS00031302, date of registration: 5th May 2023).