Project 1: SPIES: Stratifying Patient Immune Endotypes in Sepsis

This is a multicenter, prospective, observational, prognostic and diagnostic clinical study to determine whether the functional assay, ELISpot, can predict clinical trajectory in sepsis and critically ill nonseptic patients, as well as determine whether potential therapeutics can be evaluated for their efficacy, in an ex vivo setting.

Sepsis remains the leading cause of hospital mortality today.   Despite its increasing incidence due to an aging population with greater comorbidities, in-hospital mortality has significantly declined over the past decade.2  This is due in large part to earlier recognition and better compliance with best practices in early sepsis management. Despite improved in-hospital mortality, a large proportion (up to 50% in some studies) of sepsis survivors never fully recover and develop chronic critical illness (CCI),  characterized by persistent  immune suppression, recurrent infections, sepsis recidivism and poor long-term outcomes. There are three key challenges, however, hindering the development of immunological therapies in these sepsis survivors: i) how to endotype patients with sepsis who are immunosuppressed; ii) how to quantify the degree of immune suppression; and iii) how to identify promising immune stimulants in individual immunosuppressed patients? We believe that current efforts to endotype sepsis survivors as being immunosuppressed have not been fully successful because they fail to directly assess immune function, instead using either genomic or proteomic measures of immune status.

The main aims of SPIES will be to: 1) assess whether stimulated T cell production of IFN-γ and stimulated monocyte production of TNFa, as quantitated by ELISpot, better predicts infectious and long-term outcomes in sepsis survivors than common static measurements based on protein levels, expression and nucleic acid concentrations; and 2) to employ ELISpot assessment of IFN-g production by T-cells and TNFa production by monocytes from sepsis survivors to examine ex vivo the comparative efficacy of different immune stimulants to reverse sepsis-induced immunosuppression. To achieve these goals, we propose a prospective, observational trial of 270 patients with sepsis (using Sepsis-3 criteria) compared to 90 patients with critical illness without sepsis (total of 390 with 30 healthy subjects for quality control and validation) at 3 academic institutions. At 1, 4 and 7 days post sepsis diagnosis, blood samples will be obtained and blood T-cell and monocyte production of IFN-g and TNFa, respectively, will be determined by ELISpot. In addition, samples will be obtained for other biomarkers, including plasma proteins (IL-6 and sPD-L1), CD14+ cell expression of HLA-DR, total lymphocyte count and whole blood genomics. Secondary infections will be the primary clinical index of outcome6, with secondary indices including hospital readmission, and 180 day mortality. In addition, we will evaluate in this ELISpot platform the ex vivo response of IFN-g production by T-cells and TNFa production by monocytes stimulated with varying concentrations of IL-7, anti-PD-1 mAb, GITRL, OX40L or 4-1BB, using a randomized block design. These immune stimulants are currently under consideration as potential therapeutics for sepsis patients. This application proposes the validation of a novel functional bioassay to identify patients who would benefit from

SPIES Principle Investigator: