Circulating calprotectin as a marker of inflammation and sepsis

ABSTRACT

Background: Sepsis is an infection-induced syndrome of pathological and biochemical abnormalities believed to be a serious public health problem. The Third International Consensus (Sepsis-3) defined sepsis as 'a life-threatening organ threat caused by a dysregulated host response to infection'. Besides, sepsis patients with concomitant coronavirus disease (COVID-19) have been related to high morbidity and mortality rate. By its identification and characterization, fecal calprotectin (CP) has emerged as a biomarker for intestinal bowel diseases. Recently, its concentration has been documented to increase in serum and plasma samples of patients affected by autoimmune diseases. Since, the biochemical markers used in laboratory diagnosis are often unable to detect the onset of sepsis in a timely manner and given the growing interest in circulating calprotectin (cCP) as a generic marker of inflammation in recent literature, its role has been investigated in emergency room patients requiring hospitalization. Method(s) Patients were divided into four groups healthy subjects (CTRL);patients hospitalized for causes other than sepsis and negative to SARS-CoV-2 infection (GROUP 1 'NO SEPSIS');septic patients negative to SARS-CoV-2 infection (GROUP 2 SEPSIS) and septic patients positive to SARS-CoV-2 infection (GROUP 3 SEPSICOV). The cCP concentration was determined by a fully automated chemiluminescence immunoassay. Result(s) Circulating calprotectin values detected were significantly higher in groups 1, 2 and 3 (2.08 mug/mL;4.10 mug/mL;2.25 mug/mL), compared to the control group (0.50 mug/ mL) (p <0.0001), and in group 2 'SEPSIS', compared to group 1 'NO SEPSIS' (p<0.0028). The receiving operating characteristic (ROC) curves showed good AUC (area under curve)(0.888;0.945;0.922), sensitivity (80%, 86%;81%) and specificity (99%) values in group 1, 2 and 3, discriminating healthy subjects from patients. To find a cut-off value able to identify sepsis patients, data from group 2 and 3 were combined and compared to group 1 (AUC=0,598;sensitivity=60%;specificity=63%). Conclusion(s) Our results confirmed cCP as a marker of inflammation. Furthermore, the increase in cCP levels in patients with sepsis, suggests its importance as a good marker of sepsis.