Heparin binding protein in severe COVID-19-A prospective observational cohort study

Abstract

Background and aims: Neutrophil-derived heparin binding protein (HBP; also known as azurocidin or CAP-37) is a key player in bacterial sepsis and a promising biomarker in severe infections. The aims of this study were to assess whether HBP is involved in the pathophysiology of COVID-19 and, if so, whether it can be used to predict severe disease preferably using a point-of-care test.

Methods: This was a prospective convenience sample study of biomarkers in patients admitted to Skåne University hospital in Sweden with a confirmed COVID-19 diagnosis. Plasma samples and clinical data were collected within 72h after admission, during hospital stay and at discharge. Plasma HBP concentrations samples were measured both with enzyme-linked immunosorbent assay (ELISA) and with a novel dry immunofluorescence analyzer (Joinstar) point-of-care test.

Results: Thirty-five COVID-19 patients were enrolled in the study. Twenty-nine patients had blood samples taken within 72h after admission. We compared the highest HBP value taken within 72h after admission in patients who eventually developed organ dysfunction (n = 23) compared to those who did not (n = 6), and found that HBP was significantly elevated in those who developed organ dysfunction (25.0 ng/mL (interquartile range (IQR) 16.6-48.5) vs 10.6 ng/mL (IQR 4.8-21.7 ng/mL), p = 0.03). Point-of-care test measurements correlated well with ELISA measurements (R = 0.83). HBP measured by the POC device predicted development of COVID-induced organ dysfunction with an AUC of 0.88 (95% confidence interval (CI) 0.70-1.0).

Conclusions: HBP is elevated prior to onset of organ dysfunction in patients with severe COVID-19 using a newly developed point-of-care test and hence HBP could be used in a clinical setting as a prognostic marker in COVID-19.

Fig 1. Plasma concentration of HBP in patients with severe COVID-19 and other sepsis.

Plasma HBP levels measured by ELISA in patients with COVID-19, verified bacterial infection or other viral infection than COVID-19 with and without organ dysfunction (OD). Only one patient with bacterial infection did not have organ dysfunction and is not shown on the graph. HBP values in the COVID-19 cohort are the highest value measured in the first 72 hours from admission. Samples in the bacterial and other viral cohorts were taken at admission. Values were compared using Kruskal-Wallis test with Dunn’s post-hoc test for multiple comparisons.

Fig 2. Correlation between ELISA and Joinstar values.

Correlation of HBP levels in the same samples measured by Joinstar point of care device and ELISA. Correlation coefficient R = 0.8250; p<0.01). Values were compared using Spearman correlation.

Fig 3. HBP prognosticates organ dysfunction in severe COVID-19.

(A) A Receiver operating curve (ROC) of HBP measured by Joinstar point of care test (highest value in the first 72h) predicting organ dysfunction (OD) in severe COVID-19. Area under the curve is 0.86. (B) HBP levels in first sample taken within 72h after admission, within 48h before development of organ dysfunction, and within 48h before hospital discharge measured by the Joinstar point of care test. Samples from patients who developed organ dysfunction within 48h after admission were included in the “before OD” group instead of the “admission” group. Values were compared using Kruskal Wallis test with Dunn’s post-hoc test for multiple comparisons.