Interleukin-1 Receptor 2, a New Biomarker for Sepsis Diagnosis and Gram-negative/gram-positive Bacterial Differentiation

ABSTRACTThis study was undertaken to explore the value of interleukin-1 receptor 2 (IL1R2) as a novel potential biomarker for diagnosis of sepsis and discrimination of gram-negative (G)/gram-positive (G) bacterial sepsis. The study was performed in Kunming mice and septic patients. Inactive E.coli or S.aureus were used to stimulate Kunming mice (10 CFU/kg). In clinical study, septic patients with different pathogen infection were studied, and healthy volunteers and systemic inflammation response syndrome (SIRS) patients without definite infection were enrolled as control. IL1R2 transcriptions of human subjects’ peripheral leucocytes were measured by real time quantitative polymerase chain reaction (qPCR) assay. IL1R2 serum concentrations of mice and human subjects were measured by enzyme linked immune sorbent assay (ELISA). The value of IL1R2 as a biomarker was compared with procalcitonin (PCT), C reactive protein (CRP) and Acute Physiology and Chronic Health Evaluation II (APACHE II). The results showed that IL1R2 expression was up regulated in mice treated with inactive E.coli and septic patients. The elevation of serum IL1R2 was more significant in septic patients infected by E.coli or G bacteria than by S.aureus or G bacteria. For sepsis diagnosis and G/G bacterial sepsis discrimination, serum IL1R2 was more sensitive and specific than those traditional biomarkers such as PCT, CRP and APACHE II as shown by the receiver operating characteristic (ROC) curves. It was suggested that IL1R2 was a potential biomarker for diagnosis and G/G bacterial differentiation in sepsis.