Regulatory T-cell Notch4 expression correlates with mortality in hospitalized COVID-19 patients
et al., The Journal of Infectious Diseases, doi:10.1093/infdis/jiag203, Apr 2026
Analysis of peripheral circulating regulatory T (Treg) cells in 169 hospitalized patients finding that persistent Notch4 expression serves as a critical late marker of mortality after six weeks of intensive care. Authors observed that this high Notch4 expression correlates with hypoxia, immunosuppression, multiple organ failure, and a phenotypic reprogramming of Treg and T follicular regulatory (Tfr) cells toward a proinflammatory profile with decreased regulatory capacity. Authors conclude that Notch4 is a viable therapeutic target to reverse immune dysregulation and treat late-stage, critically ill patients.
Alkarkoukly et al., 9 Apr 2026, peer-reviewed, 6 authors.
DOI record:
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"abstract": "<jats:title>Abstract</jats:title>\n <jats:sec>\n <jats:title>Purpose</jats:title>\n <jats:p>Severe COVID-19 is characterized by profound immune dysregulation, yet the mechanisms distinguishing fatal from non-fatal outcomes remain incompletely understood. Regulatory T (Treg) cells have been shown to play a central role in regulating immune responses and promoting tissue repair. In this study, we investigate the expression of Notch4 on peripheral circulating Treg cells in 169 hospitalized COVID-19 patients and evaluate its association with clinical outcomes.</jats:p>\n </jats:sec>\n <jats:sec>\n <jats:title>Results</jats:title>\n <jats:p>Our analysis divulges that Notch4 expression on Treg cells correlates significantly with death in patients after six weeks of intensive care unit (ICU) admission, correlating with hypoxia, immunosuppression, and multiple organ failure. Unlike early-phase inflammatory cytokines such as IL-6, IL-8, and IL-10—whose upregulation was observed during the first two weeks—Notch4 expression emerges as a late marker, specifically distinguishing patients who eventually succumb to the disease. Similar to earlier reports, deeper immune profiling of Regulatory cells identified a short of both reg and T follicular regulatory (Tfr) cells in deceased patients toward a proinflammatory profile, suggesting phenotypic reprogramming. In our previous studies, Notch4 expression was strongly associated with decreased regulatory capacity and increased immune activation. Our results indicate that persistent Notch4+ Treg signatures, particularly after 6 weeks of ICU admission, serve as critical markers of mortality in COVID-19.</jats:p>\n </jats:sec>\n <jats:sec>\n <jats:title>Conclusion</jats:title>\n <jats:p>Notch4 can be used as a viable therapeutic target to restore immune homeostasis in critically ill patients. Further studies are still needed to understand the role of Treg cell Notch4 expression in other viral acute respiratory distress syndromes (ARDS).</jats:p>\n </jats:sec>",
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"name": "Medical Data Integration Center (MeDIC), Faculty of Medicine and University Hospital Cologne, University of Cologne , Cologne ,",
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"name": "Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital Cologne, University of Cologne , Cologne ,",
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"family": "Hambo",
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"family": "Menk",
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"title": "Regulatory T-cell Notch4 expression correlates with mortality in hospitalized COVID-19 patients",
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