Increased plasma level of soluble P-selectin in non-hospitalized COVID-19 convalescent donors
Rebecca Müller1, Gabi Rink1, Günalp Uzun2
1Institute of Transfusion Medicine and Immunology, Heidelberg University, Medical Faculty Mannheim, German Red Cross Blood Service Baden-Württemberg - Hessen, Mannheim, Germany.
Insights
Elevated soluble P-selectin (sP-sel) levels, a marker of platelet activation, persist for weeks after moderate COVID-19. However, in vitro platelet function returns to normal, suggesting other factors contribute to elevated sP-sel post-COVID-19.
Area of Science:
- Cardiovascular biology
- Hematology
- Infectious diseases
Background:
- Coronavirus disease-2019 (COVID-19) significantly impacts the vascular and coagulation systems.
- A procoagulant platelet phenotype is observed during acute COVID-19.
- Soluble P-selectin (sP-sel) is a plasma biomarker for platelet activation, with elevated levels linked to COVID-19 severity.
Purpose of the Study:
- To longitudinally evaluate plasma sP-sel concentrations in blood donors who recovered from moderate COVID-19.
- To assess if platelet activation markers remain elevated weeks after infection.
- To compare platelet function between COVID-19 convalescent donors and non-infected controls.
Main Methods:
- A longitudinal study involving 154 COVID-19 convalescent and 111 control donors.
- Plasma samples collected at three time points (T1, T2, T3) post-COVID-19 diagnosis.
- sP-sel plasma concentration measured using ELISA; platelet function assessed via flow cytometry and aggregometry in a subgroup.
Main Results:
- COVID-19 convalescent donors showed significantly higher plasma sP-sel levels at T1 (43-378 days post-diagnosis) and T2 compared to controls.
- sP-sel levels decreased over time, becoming comparable between groups by T3.
- In vitro platelet function was similar between convalescent and control donors at T1.
Conclusions:
- Elevated plasma sP-sel, indicating platelet or endothelial activation, persists for weeks after moderate COVID-19.
- Despite elevated sP-sel, in vitro platelet function normalizes, suggesting additional factors influence sP-sel levels.
- COVID-19 may lead to sustained increases in sP-sel, potentially influenced by individual factors.
Background:
The coronavirus disease-2019 (COVID-19) is a systemic disease with severe implications on the vascular and coagulation system. A procoagulant platelet phenotype has been reported at least in the acute disease phase. Soluble P-selectin (sP-sel) in the plasma is a surrogate biomarker of platelet activation. Increased plasma levels of sP-sel have been reported in hospitalized COVID-19 patients associated with disease severity. Here, we evaluated in a longitudinal study the sP-sel plasma concentration in blood donors who previously suffered from moderate COVID-19.
Methods:
154 COVID-19 convalescent and 111 non-infected control donors were recruited for plasma donation and for participation in the CORE research trial. First donation (T1) was performed 43-378 days after COVID-19 diagnosis. From most of the donors the second (T2) plasma donation including blood sampling was obtained after a time period of 21-74 days and the third (T3) donation after additional 22-78 days. Baseline characteristics including COVID-19 symptoms of the donors were recorded based on a questionnaire. Platelet function was measured at T1 by flow cytometry and light transmission aggregometry in a representative subgroup of 25 COVID-19 convalescent and 28 control donors. The sP-sel plasma concentration was determined in a total of 704 samples by using a commercial ELISA.
Results:
In vitro platelet function was comparable in COVID-19 convalescent and control donors at T1. Plasma samples from COVID-19 convalescent donors revealed a significantly higher sP-sel level compared to controls at T1 (1.05 ± 0.42 ng/mL vs. 0.81 ± 0.30 ng/mL; p < 0.0001) and T2 (0.96 ± 0.39 ng/mL vs. 0.83 ± 0.38 ng/mL; p = 0.0098). At T3 the sP-sel plasma level was comparable in both study groups. Most of the COVID-19 convalescent donors showed a continuous decrease of sP-sel from T1 to T3.
Conclusion:
Increased sP-sel plasma concentration as a marker for platelet or endothelial activation could be demonstrated even weeks after moderate COVID-19, whereas, in vitro platelet function was comparable with non-infected controls. We conclude that COVID-19 and additional individual factors could lead to an increase of the sP-sel plasma level.
