Serum calprotectin can indicate current and future severity of COVID‐19

• Published in: Journal of clinical laboratory analysis Vol. 37; no. 1; pp. e24809 - n/a
• Main Authors: Shokri‐Afra, Hajar, Moradi, Mona, Musavi, Hadis, Moradi‐Sardareh, Hemen, Moradi poodeh, Bahman, Kazemi Veisari, Arash, Oladi, Ziaeddin, Ebrahimi, Mahboobe
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01-01-2023
• Subjects: Biomarkers; Body mass index; calprotectin; Cell activation; Chronic obstructive pulmonary disease; Coronaviruses; COVID-19; COVID-19 - diagnosis; Cytokines; Hospitalization; Hospitals; Humans; IL‐6; Immune response; Immune system; Inflammation; inflammatory biomarkers; Inflammatory bowel disease; Interleukin 6; Laboratories; Leukocyte L1 Antigen Complex; Leukocytes (neutrophilic); Neutrophils; outcome; Oxygenation; Prospective Studies; Regression analysis; Rheumatoid arthritis; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Severity of Illness Index; Statistical analysis; Variance analysis; Ventilators; COVID-19; inflammatory biomarkers; calprotectin; IL-6; outcome
• ISSN: 0887-8013; 1098-2825
• DOI: 10.1002/jcla.24809

Background
Predictive and prognostic biomarkers to guide 2019 novel coronavirus disease (COVID‐19) are critically evolving. Dysregulated immune responses are the pivotal cause of severity mainly mediated by neutrophil activation. Thus, we evaluated the association of calprotectin, neutrophil secretory protein, and other mediators of inflammation with the severity and outcomes of COVID‐19.
Methods
This two‐center prospective study focused on PCR‐proven COVID‐19 patients (n = 76) with different clinical presentations and SARS‐CoV‐2 negative control subjects (n = 24). Serum calprotectin (SC) was compared with IL‐6 and other laboratory parameters.
Results
Median levels of SC were significantly higher in COVID‐19 patients in comparison to the control group (3760 vs. 2100 ng/ml, p < 0.0001). Elevated SC was significantly respective of disease severity (3760 ng/ml in mild up to 5700 ng/ml in severe cases, p < 0.0001). Moreover, the significant positive and negative correlations of SC with disease severity and oxygenation status indicated disease progression and respiratory worsening, respectively. It was found that SC was high in severe patients during hospitalization and significantly declined to normal after recovery. The logistic analysis identified the independent predictive power of SC for respiratory status or clinical severity. Indeed, SC behaved as a better discriminator for both outcomes, as it exhibited the largest area under the curve (receiver operating curve analysis), with the highest specificity and sensitivity when the predictive value of inflammatory biomarkers was compared.
Conclusion
Calprotectin can be used as a reliable prognostic tool to predict the poor clinical outcomes of COVID‐19 patients.
SC and IL‐6 had a disease severity‐dependent response for COVID‐19 patients. However, SC content exhibited a better‐differentiated pattern in which it increased significantly with the exacerbation of disease clinical symptoms. Mild to severe subgroups had significantly different SC and IL‐6 levels, regardless of how many days had elapsed since the disease onset. Indeed, SC and IL‐6 levels were not affected by the time of sampling indicating a contiguous inflammatory status in patients because inflammatory markers decreasing reflects attenuating inflammation and consequently an improvement in disease severity. As we observed that SC and IL‐6 levels significantly reduced to normal in recovered patients and were comparable to control cases. Of note, their decrease was respective of disease severity. In general, SC was found as a more reliable marker than IL‐6 in the COVID‐19 investigation.