The number of circulating CD26 expressing cells is decreased in critical COVID-19 illness

Area of Science:

• Immunology
• Virology
• Clinical Medicine

Background:

• COVID-19 is an infectious disease with significant morbidity and mortality.
• Understanding immune cell dynamics is crucial for predicting disease severity and treatment response.
• CD26 (dipeptidyl peptidase-4) is a cell surface molecule expressed on various immune cells, including T lymphocytes.

Purpose of the Study:

• To investigate the association between CD26 expressing cells in peripheral blood and COVID-19 severity.
• To evaluate CD26 T cell dynamics during the initial week of standard COVID-19 treatment.
• To explore the potential of CD26 as a biomarker for disease outcome and therapeutic efficacy.

Main Methods:

• Quantification of CD26 expressing cells in peripheral blood of COVID-19 patients.
• Analysis was performed within 72 hours of admission, and on days 4 and 7 post-enrollment.
• Flow cytometry was used to identify and enumerate CD26 expressing cells, primarily CD3+ CD4+ lymphocytes.

Main Results:

• A low number of CD26 expressing cells correlated with critical COVID-19 severity.
• Increasing numbers of CD26 expressing T cells during the first week of treatment were associated with favorable outcomes.
• The majority of CD26 expressing cells were identified as CD3+ CD4+ T lymphocytes.

Conclusions:

• Circulating CD26 cell counts may serve as a valuable biomarker for monitoring COVID-19 recovery.
• CD26 levels can indicate the therapeutic efficacy of anti-COVID-19 treatments.
• Therapeutic strategies aimed at preserving or increasing CD26 expressing T cells could be beneficial for COVID-19 patients.