Validation of the new Sepsis-3 definitions: proposal for improvement in early risk identification

OBJECTIVES

Sepsis-3 definitions generated controversies regarding their general applicability. The Sepsis-3 Task Force outlined the need for validation with emphasis on the quick Sequential Organ Failure Assessment (qSOFA) score. This was done in a prospective cohort from a different healthcare setting.

METHODS

Patients with infections and at least two signs of systemic inflammatory response syndrome (SIRS) were analysed. Sepsis was defined as total SOFA ≥2 outside the intensive care unit (ICU) or as an increase of ICU admission SOFA ≥2. The primary endpoints were the sensitivity of qSOFA outside the ICU and sepsis definition both outside and within the ICU to predict mortality.

RESULTS

In all, 3346 infections outside the ICU and 1058 infections in the ICU were analysed. Outside the ICU, respective mortality with ≥2 SIRS and qSOFA ≥2 was 25.3% and 41.2% (p <0.0001); the sensitivities of qSOFA and of sepsis definition to predict death were 60.8% and 87.2%, respectively. This was 95.9% for sepsis definition in the ICU. The sensitivity of qSOFA and of ≥3 SIRS criteria for organ dysfunction outside the ICU was 48.7% and 72.5%, respectively (p <0.0001). Misclassification outside the ICU with the 1991 and Sepsis-3 definitions into stages of lower severity was 21.4% and 3.7%, respectively (p <0.0001) and 14.9% and 3.7%, respectively, in the ICU (p <0.0001). Adding arterial pH ≤7.30 to qSOFA increased sensitivity for prediction of death to 67.5% (p 0.004).

CONCLUSIONS

Our analysis positively validated the use of SOFA score to predict unfavourable outcome and to limit misclassification into lower severity. However, qSOFA score had inadequate sensitivity for early risk assessment.

Development of a sensitive cost-effective capture ELISA for detection of murine monoclonal antibodies: correlation with SPR biosensor technology

The development of antibodies for diagnostic and therapeutic applications in inflammatory diseases is a major focus for biotechnology and pharmaceutical companies. Production of monoclonal antibodies requires the development of fast, high-throughput methodologies for screening and selecting appropriate candidate antibodies for development. Capture (sandwich) enzyme linked immunosorbent assay (ELISA) provides a quick and reliable method that could be used for hybridoma screening of potential candidates accompanied with surface plasmon resonance (SPR) biosensor technology for identifying high affinity biomolecular interactions. A sensitive, cost-effective, robust and accurate capture ELISA for detection of murine monoclonal antibodies in culture supernatants was developed. This assay was optimized for high sensitivity and specificity with a capture anti-mouse polyclonal antibody. Using serial dilutions of a defined murine IgG antibody, a linear dose-response was observed between 2 and 1200 ng/ml antibody with a coefficient of determination r2 of 0.98. The detection limit of the assay was established as 2ng/ml (12.5pM). A similar concentration-dependent doseresponse was also observed using serial dilutions of antibody-containing supernatants from anti-alpha glycophorinproducing hybridomas (detection limit 1:2000). Specific capture of antibodies from supernatants in a similar setting was also confirmed using SPR biosensor technology and correlated well with the immunoassay results. The latter technology can be performed in order to provide quick screening results and kinetic analysis of antibody binding interactions aiming at identifying candidates with high affinity and specificity.

RAIDD is required for apoptosis of PC12 cells and sympathetic neurons induced by trophic factor withdrawal

Caspase 2 has been implicated in trophic deprivation-induced neuronal death. We have shown that overexpression of the caspase 2-binding protein RAIDD induces neuronal apoptosis, acting synergistically with trophic deprivation. Currently, we examine the role of endogenous RAIDD in apoptosis of PC12 cells and sympathetic neurons. Expression of a truncated caspase recruitment domain-only form of caspase 2, which presumably disrupts the RAIDD interaction with endogenous caspase 2, attenuated trophic deprivation-induced apoptosis. Furthermore, downregulation of RAIDD by small interfering RNA led to inhibition of trophic deprivation-induced death, whereas death induced by DNA damage, which is not caspase 2-mediated, was not inhibited. Therefore, RAIDD, likely through interaction with caspase 2, is involved in trophic deprivation-induced neuronal apoptosis. This is the first demonstration of the involvement of RAIDD in apoptosis, and provides further support for the idea that apoptotic pathways in the same system may differ depending on the initiating stimulus.