Inflammatory markers calprotectin, NETs, syndecan-1 and neopterin in COVID-19 convalescent blood donors

Figures & data

Table 1. Characteristics of COVID-19 convalescent blood donors, median and (range).

Age	Gender	Days of illness	Number^a of symptoms
46 (27–74)	60% F	14 (2–49)	3 (1–8)

Population characteristics among 61 reachable convalescents.

^aTotally 12 symptoms.

Figure 1. Levels of calprotectin measured by novel mixed monoclonal assay in COVID-19 convalescent blood donors and non-COVID-19 controls.

Table 2. Levels of Syndecan-1, neopterin and CRP in COVID-19 convalescent blood donors and non-COVID-19 controls; healthy employees at the Blood bank and healthy blood donors who were unvaccinated and without COVID-19 antibodies.

Analyses	Subjects		p value
	COVID-19 convalescents	Controls
Syndecan-1 (ng/mL)	103.64 ± 84.83/ 69.11 (11.80 − 353.40)	90.57 ± 82.17/ 52.40 (25.12 − 289.38)	.137
Neopterin (mmol/L)	8.65 ± 2.26/ 8.77 (3.95 − 13.31)	8.74 ± 2.00/ 9.05 (2.86 − 13.46)	.821
^aCRP (mg/L)	4.17 ± 4.73 2.70 (1.8–30.0)	2.70 ± 1.84 1.8 (1.8–6.0)	.080

Data is mean ±SD and median (range). Statistics was t-test or Wilcoxon–MWU.

^aOnly measurable in remaining 40 convalescent and five control samples.

Table 3. Correlations between values for inflammatory markers, and between these and antibody levels in COVID-19 convalescents.

Pearson correlation coefficient (rr)
Parameters	Calprotectin	Syndecan-1	Neopterin	Anti-N Ab
Calprotectin	1	0.227*	0.152	0.024
Syndecan-1		1	0.099	–0.036
Neopterin			1	0.009
Anti-N Ab				1

*p = .009.

Data availability statement

The data supporting the findings of this study are available from the corresponding author upon request. The complete data are not publicly available due to ethical restrictions.