Predicting Organ Dysfunction in Septic and Critically Ill Patients: A Prospective Cohort Study Using Rapid Ex Vivo Immune Profiling

Abstract

OBJECTIVES: While cytokine response patterns are pivotal in mediating immune responses, they are also often dysregulated in sepsis and critical illness. We hypothesized that these immunological deficits, quantifiable through ex vivo whole blood stimulation assays, may be indicative of subsequent organ dysfunction. DESIGN: In a prospective observational study, adult septic patients and critically ill but nonseptic controls were identified within 48 hours of critical illness onset. Using a rapid, ex vivo assay based on responses to lipopolysaccharide (LPS), anti-CD3/anti-CD28 antibodies, and phorbol 12-myristate 13-acetate with ionomycin, cytokine responses to immune stimulants were quantified. The primary outcome was the relationship between early cytokine production and subsequent organ dysfunction, as measured by the Sequential Organ Failure Assessment score on day 3 of illness (SOFAd3). SETTING: Patients were recruited in an academic medical center and data processing and analysis were done in an academic laboratory setting. PATIENTS: Ninety-six adult septic and critically ill nonseptic patients were enrolled. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Elevated levels of tumor necrosis factor and interleukin-6 post-endotoxin challenge were inversely correlated with SOFAd3. Interferon-gamma production per lymphocyte was inversely related to organ dysfunction at day 3 and differed between septic and nonseptic patients. Clustering analysis revealed two distinct immune phenotypes, represented by differential responses to 18 hours of LPS stimulation and 4 hours of anti-CD3/anti-CD28 stimulation. CONCLUSIONS: Our rapid immune profiling technique offers a promising tool for early prediction and management of organ dysfunction in critically ill patients. This information could be pivotal for early intervention and for preventing irreversible organ damage during the acute phase of critical illness.

Time-Dependent Variation in Immunoparalysis Biomarkers Among Patients with Sepsis and Critical Illness

“…The production of TNF was normalized to the monocyte count, and IFNγ production was normalized to the lymphocyte count, based on daily complete blood counts with automated differential profiles [16,43]. Due to the varied cellular sources of IL-6, its production was normalized to the total leukocyte count [27].…”

“…Based in part on these insights, our lab has pioneered a fast and precise assay for detecting immunoparalysis. We recently reported that ex vivo stimulation of both innate and adaptive immune system components did not predict secondary infection rates but reliably predicted organ function within 48 hours of the assay [27]. Clustering analysis further revealed two distinct immune phenotypes, characterized by differential responses to 18 hours of lipopolysaccharide (LPS, or endotoxin) and 4 hours of anti-CD3/anti-CD28 stimulation.…”