Project Summary/Abstract Sepsis is a global epidemic with a high patient morbidity and mortality, and it accounts for staggering healthcare costs both within the US and worldwide. Clinicians caring for septic patients are unable to distinguish between septic patients who will rapidly recover and those patients who will develop a prolonged disease course marked by immune dysfunction, infectious complications, chronic critical illness (CCI) and death. This affects their ability to weigh the clinical risks versus benefits of immune-adjuvant therapy, in cases where sepsis is characterized by marked immune paralysis. The long-term research goals are (1) to develop novel, rapid and personalized tools with which to predict the prognostic trajectory of septic patients based on underlying immune phenotype, and (2) to integrate this information into the clinical care of septic patients. The subject of this proposal encompasses the first of these two goals, with objectives aligning with the NIGMS Sepsis Research priorities (NOT-GM-19-054). Specifically, we will continue recruitment into an ongoing, prospective, observational, clinical research trial enrolling patients suffering from acute sepsis at a tertiary care, academic medical center. We will utilize a combination of immune-based assays and computational approaches to (i) Validate the prognostic value of rapid, microfluidic cytokine analysis, following ex vivo stimulation of whole blood. Hypothesis: functional immune phenotyping can identify septic patients with subclinical immune paralysis who are prone to secondary infections. Approach: Quantitative analyses comparing cytokine responses to immune adjuvants before and after ex vivo stimulation of whole blood. Microfluidic cytokine analysis provides rapid and precise measurements and that are compatible with a clinical, point of care test. (ii) Compare the CCI syndrome following medical and surgical sepsis. Hypothesis: Iatrogenic tissue damage and inflammation caused by surgery alters the immune response and pathophysiology of CCI in surgical patients, as compared with medical patients. We will use a combination of transcriptomic and metabolomic data to confirm current theories of CCI pathophysiology in surgical patients, and then explore how it differs in patients having medical sepsis. (iii) Develop high fidelity, in vitro models of human myeloid-derived suppressor cells (MDSCs) with which to perform preclinical testing of potential therapies for sepsis-induced CCI. Hypothesis: human MDSCs (immature myeloid cells that expand during chronic infection and suppress immune responses) can be generated through differentiation from peripheral blood mononuclear cells isolated from whole blood. These cells can be used as a novel preclinical model with which to test potential therapies for CCI that are extrapolated from the treatment of cancer. The PI of this grant application is a clinician- scientist and the current recipient of a K08 award from the NIGMS which studies sepsis. He is ready to progress to scientific independence via the R-35 grant mechanism for early-stage investigators.

Project Narrative Sepsis is a global epidemic with a high disease burden, although clinicians caring for septic patients are unable to distinguish between septic patients who will rapidly recover and those who will develop a prolonged disease course marked by significant morbidity and mortality. This is partly due to our incomplete understanding of the complex underlying immune responses in sepsis as well as our inability to translate research findings into information that is useful to clinicians. This research will contribute to the development of novel techniques that will help clinicians to get individualized results about their patients’ immune responses, to guide their decisions about whether immune-adjuvant therapy may be appropriate for each patient.