Serial measurement of circulating calprotectin as a prognostic biomarker in COVID-19 patients in intensive care setting.

OBJECTIVES: Circulating calprotectin (cCLP) has been shown to be a promising prognostic marker for COVID-19 severity. We aimed to investigate the prognostic value of serial measurements of cCLP in COVID-19 patients admitted to an intensive care unit (ICU). METHODS: From November 2020 to May 2021, patients with COVID-19, admitted at the ICU of the OLV Hospital, Aalst, Belgium, were prospectively included. For sixty-six (66) patients, blood samples were collected at admission and subsequently every 48 h during ICU stay. On every sample (total n=301), a cCLP (EliA™ Calprotectin 2, Phadia 200, Thermo Fisher Scientific; serum/plasma protocol (for Research Use Only, -RUO-) and C-reactive protein (CRP; cobas c501/c503, Roche Diagnostics) analysis were performed. Linear mixed models were used to associate biomarkers levels with mortality, need for mechanical ventilation, length of stay at ICU (LOS-ICU) and medication use (antibiotics, corticosteroids, antiviral and immune suppressant/modulatory drugs). RESULTS: Longitudinally higher levels of all biomarkers were associated with LOS-ICU and with the need for mechanical ventilation. Medication use and LOS-ICU were not associated with variations in cCLP and CRP levels. cCLP levels increased significantly during ICU hospitalization in the deceased group (n=21/66) but decreased in the non-deceased group (n=45/66). In contrast, CRP levels decreased non-significantly in both patient groups, although significantly longitudinally higher CRP levels were obtained in the deceased subgroup. CONCLUSIONS: Serial measurements of cCLP provides prognostic information which can be useful to guide clinical management of COVID-19 patients in ICU setting.

Clinical utility of circulating calprotectin to assist prediction and monitoring of COVID-19 severity: An Italian study.

BACKGROUND: Calprotectin (S100A8/A9) has been identified as a biomarker that can aid in predicting the severity of disease in COVID-19 patients. This study aims to evaluate the correlation between levels of circulating calprotectin (cCP) and the severity of COVID-19. METHODS: Sera from 245 COVID-19 patients and 110 apparently healthy individuals were tested for calprotectin levels using a chemiluminescent immunoassay (Inova Diagnostics). Intensive care unit (ICU) admission and type of respiratory support administered were used as indicators of disease severity, and their correlation with calprotectin levels was assessed. RESULTS: Samples from patients in the ICU had a median calprotectin concentration of 11.6 µg/ml as compared to 3.5 µg/ml from COVID-19 patients who were not in the ICU. The median calprotectin concentration in a cohort of healthy individuals collected before the COVID-19 pandemic was 3.0 µg/ml (95% CI: 2.820-2.969 µg/ml). Patients requiring a Venturi mask, continuous positive airway pressure, or orotracheal intubation all had significantly higher values of calprotectin than controls, with the increase of cCP levels proportional to the increasing need of respiratory support. CONCLUSION: Calprotectin levels in serum correlate well with disease severity and represent a promising serological biomarker for the risk assessment of COVID-19 patients.

Circulating calprotectin as a supporting inflammatory marker in discriminating SARS-CoV-2 infection: an observational study.

OBJECTIVE AND DESIGN: Fecal calprotectin (CLP) is widely known for its detection in stools of patients with inflammatory bowel diseases (IBDs), to investigate the intestinal inflammatory status. Current research is promoting the circulating protein role as a systemic inflammatory marker. However, most studies report serum calprotectin analysis although plasma assay prevents its massive release by granulocytes. In this perspective, the ongoing SARS-CoV-2 pandemic deserves deployment of convenient and easy-to-dose markers that could reliably address the state of infection. METHODS: We analyzed serum circulating calprotectin (cCLP) levels in hospitalized COVID-19 patients and plasma cCLP levels from patients with suspected SARS-CoV-2 infection, then assessed negative or positive on molecular tests. RESULTS: Our results confirm a significant circulating calprotectin increase in infected subjects respect to controls, in serum and plasma. Moreover, plasma calprotectin has higher levels in suspected patients with positive SARS-CoV-2-RT-PCR, compared to suspected patients with negative SARS-CoV-2-RT-PCR. Furthermore, ROC curves results showed the circulating plasma calprotectin discriminatory ability to differentiate infected SARS-CoV-2 patients at a cutoff value greater than 131.3 ng/ml. CONCLUSIONS: Our data propose circulating calprotectin as a new, quantitative and predictive marker, which in addition to being an interesting generic inflammatory marker may provide important indications in SARS-CoV-2 infection.