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Dynamic Changes of Lymphocyte Subsets in the Course of COVID-19
Mitra Rezaei1,2, Majid Marjani3, Shima Mahmoudi4
1Virology Research Center, National Research Institute of Tuberculosis and Lung diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Insights
Dynamic changes in lymphocyte subsets, including CD4+ and CD8+ T cells, predict clinical response in COVID-19 patients. Increased T cell counts indicate a better prognosis, aiding understanding of immune dysfunction in the disease.
Area of Science:
- Immunology
- Virology
- Infectious Diseases
Background:
- COVID-19 pathophysiology is not fully understood, but immune system dysfunction is a leading hypothesis.
- Investigating dynamic changes in lymphocyte subsets offers insight into COVID-19 immune responses.
Purpose of the Study:
- To characterize dynamic changes in peripheral lymphocyte subsets during COVID-19.
- To determine the clinical significance of these changes in relation to patient outcomes.
Main Methods:
- Prospective study of 52 hospitalized COVID-19 patients.
- Flow cytometry used to measure lymphocyte subsets (CD4+, CD8+, CD19+, etc.) at admission and after 7 days.
- Clinical response categorized as early, late, or non-responders based on symptom improvement and survival.
Main Results:
- Significant increases in white blood cell, CD4+ T cells, CD8+ T cells, CD38+, and CD3+HLA-DR+ lymphocytes observed in responders.
- No significant differences in CD4+/CD8+ ratio, B cells, or FOXP3+Treg cells.
- Increased CD4+ T cells, CD8+ T cells, and interferon administration were independent predictors of clinical response.
Conclusions:
- An increasing trend in T cells, activated lymphocytes, and NK cells was noted in responders but not non-responders.
- These findings contribute to understanding COVID-19 pathogenesis and immune system involvement.
- Dynamic monitoring of lymphocyte subsets may offer prognostic value in COVID-19.
Background:
Although the pathophysiology of coronavirus disease 2019 (COVID-19) is not clearly defined, among the proposed mechanisms, immune system dysfunction is more likely than others. The aim of this study was to clarify the characteristics and clinical significance of dynamic changes of lymphocyte subsets in the course of COVID-19.
Methods:
In this prospective study, the levels of peripheral lymphocyte subsets including CD4+, CD8+, CD4+CD25+FOXP3+, CD38+, CD3+HLA-DR+, CD19+, CD20+, and CD16+CD56+ cells were measured by flow cytometry in 52 confirmed hospitalized patients with COVID-19 at the day of admission and after 7 days of care. Clinical response was defined as improvement in symptoms (fever, dyspnea, and cough as well as blood oxygen saturation), and patients who met these criteria after 1 week of admission were classified as early responders; others who survived and finally discharged from the hospital were classified as late responders and patients who died were categorized as nonresponders. Immunophenotyping of studied cell changes on the first day of admission and 7 days after treatment were compared. Besides, the correlation between cellular subset variation and clinical response and outcome were analyzed.
Results:
Total counts of white blood cell, T cells, CD4+ T cells, CD8+ T cells, CD38+ lymphocytes, and CD3+HLA-DR+ lymphocytes were significantly increased in both early and late responders. No statistically significant difference was observed in CD4+/CD8+ ratio, B cells, FOXP3+Treg lymphocytes, and FOXP3 median fluorescence intensity among studied groups. According to the multivariate analysis, an increase in CD4+ T cells (p = 0.019), CD8+ T cells (p = 0.001), and administration of interferon (p < 0.001) were independent predictors of clinical response.
Conclusion:
We found an increasing trend in total T cells, T helpers, cytotoxic T cells, activated lymphocytes, and natural killer cells among responders. This trend was not statistically significant among nonresponders. The findings of this study may enhance our knowledge about the pathogenesis of COVID-19.
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