Figure legends
Figure 1: Evaluation of serological markers indicating intestinal barrier leakage and damage. PCS patients exhibited significantly higher serum levels of Lipopolysaccharide-binding protein (LBP) compared to convalescent SARS-CoV-2 participants and healthy controls (A). In contrast, serum levels of sCD14 were significantly lower in PCS patients than in all other groups (B). When examining the LBP/sCD14 ratio, PCS patients again showed a significantly higher ratio compared to convalescent SARS-CoV-2 participants and healthy controls (C). Serum levels of I-FABP showed no differences between the groups (D). Kruskal-Wallis test and Dunn’s multiple comparison test were used to identify significant differences between all test groups. * p<0.05. **p<0.01. ***p<0.001
Figure 2 : Evaluation of pro-inflammatory immune mediators and cytokines related to intestinal barrier integrity. Serum samples were analyzed for IFN-γ, TNF-α, IL-6, IL-1-β, IL-8, and IL-33. Significant increases in IL-6 levels and decreases in serum and IL-1-β levels were observed in PCS patients (A-C). However, many pro-inflammatory cytokine ELISA results were below the manufacturer’s Limit of Detection (LOD) and had to be excluded before statistical analysis. Serum IL-33 levels were significantly lower in PCS patients compared to SARS-CoV-2 negative control participants (D). Data on IL-8 and IFN-γ levels are not shown as they did not exhibit statistical significance or a disease-specific pattern. Kruskal-Wallis test and Dunn’s multiple comparison test were used to identify significant differences between all test groups. * p<0.05. **p<0.01. ***p<0.001
Author contributions
RJ and UE involved in conceptualization. RJ, and KL and involved in methodology. RJ, WV, SJ and ZS involved in formal analysis. SM and UE involved in resources. RJ, WV and SJ involved in data curation. RJ and UE involved in writing original draft preparation. RJ, WV, SJ, KL, SM, ZS and UE involved in writing—review and editing. RJ and UE involved in visualization. UE involved in supervision and project administration. UE involved in funding acquisition.
All authors have read and agreed to the published version of the manuscript.
Acknowledgments
We like to thank all PCS and ME/CFS patients and other participants who made this scientific study possible. Your contributions have enriched our research, providing valuable insights that will help improve diagnosis and treatment.
Funding information
The project was partially supported by WE&ME Foundation and the “Medizinisch-Wissenschaftlicher Fonds des Buergermeisters der Bundeshauptstadt Wien” (Medical-Scientific Fund of the Major of Vienna; project number: 22094). The sponsors had no role in the design, execution, interpretation, or writing of the study.
Conflict of interests
The authors declare no conflict of interest.
Institutional Review Board Statement
The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethics Committee of the Medical University of Vienna (vote number: 2281/2020; approved: January 19th 2021).
Informed Consent Statement
Informed consent was obtained from all subjects involved in the study.
Data Availability Statement
The raw data supporting the conclusions of this article will be made available by the authors on request.