Clinical significance of cytokeratin 19 fragment in COVID-19 patients: a retrospective study
Clinical significance of cytokeratin 19 fragment in COVID-19 patients: a retrospective study
Background: Cytokeratin 19 fragment (CYFRA 21-1) is an important biomarker of lung cancer. There are clinical observations of elevated serum levels of lung cancer biomarkers in patients with viral pneumonia. However, the clinical significance of CYFRA 21-1 in coronavirus disease 2019 pneumonia has not been investigated. Methods: This retrospective study included 252 patients with community-acquired pneumonia (CAP) between December 1, 2022, and September 30, 2023. They were classified into three groups by clinical diagnosis and severity, namely mild non-COVID-19 CAP (n = 86), mild COVID-19 (n = 100), and severe COVID-19 (n = 66). Demographic characteristics, history, outcomes, and laboratory tests, including CYFRA 21-1 levels, were collected and compared among the groups. Risk factors associated with the diagnosis of COVID-19 pneumonia and severity were explored using appropriate statistical methods. Results: CYFRA 21-1 levels progressively increased from mild non–COVID-19 CAP to mild COVID-19 and severe COVID-19. Lower lymphocyte and platelet counts, alongside elevated CYFRA 21-1 levels, were associated with COVID-19 pneumonia. Multivariate analysis identified CYFRA 21-1 as an independent diagnostic [diagnosis odds ratio (OR) = 2.369; 95% confidence interval (CI) = 1.638–3.605; p < 0.001] and prognosis factor of COVID-19 pneumonia (severity OR = 1.416; 95% CI = 1.119–1.867; p = 0.01). The area under the receiver operating characteristic curve of CYFRA 21-1 for predicting the development of severe COVID-19 pneumonia was 0.913. Spearman analysis showed a negative correlation between CYFRA 21-1 levels and oxygenation index, with a correlation coefficient of −0.278 (p = 0.024). Conclusion: CYFRA 21-1 may be a potential diagnostic and prognostic indicator of COVID-19 pneumonia. Prospective multicenter studies are needed to confirm its clinical value.
COVID-19, CYFRA 21-1, cancer biomarkers, risk stratification, viral pneumonia
Shen, Simei
950f6d14-7839-40d3-bc13-3eb87568c645
Wu, Dandan
218df870-1849-4a0f-8234-83f14e9832b5
Xie, Haiqin
907b4754-ca63-42c3-a033-ca79875a0345
He, Haiyan
a1db6ef6-dd39-4613-8d17-f760c1a3ab71
Wang, Yihua
f5044a95-60a7-42d2-87d6-5f1f789e3a7e
Lv, Xuedong
afac5371-0a4b-4cc5-8915-ac2c926e3a11
18 December 2025
Shen, Simei
950f6d14-7839-40d3-bc13-3eb87568c645
Wu, Dandan
218df870-1849-4a0f-8234-83f14e9832b5
Xie, Haiqin
907b4754-ca63-42c3-a033-ca79875a0345
He, Haiyan
a1db6ef6-dd39-4613-8d17-f760c1a3ab71
Wang, Yihua
f5044a95-60a7-42d2-87d6-5f1f789e3a7e
Lv, Xuedong
afac5371-0a4b-4cc5-8915-ac2c926e3a11
Shen, Simei, Wu, Dandan, Xie, Haiqin, He, Haiyan, Wang, Yihua and Lv, Xuedong
(2025)
Clinical significance of cytokeratin 19 fragment in COVID-19 patients: a retrospective study.
Frontiers in Public Health, 13, [1738947].
(doi:10.3389/fpubh.2025.1738947).
Abstract
Background: Cytokeratin 19 fragment (CYFRA 21-1) is an important biomarker of lung cancer. There are clinical observations of elevated serum levels of lung cancer biomarkers in patients with viral pneumonia. However, the clinical significance of CYFRA 21-1 in coronavirus disease 2019 pneumonia has not been investigated. Methods: This retrospective study included 252 patients with community-acquired pneumonia (CAP) between December 1, 2022, and September 30, 2023. They were classified into three groups by clinical diagnosis and severity, namely mild non-COVID-19 CAP (n = 86), mild COVID-19 (n = 100), and severe COVID-19 (n = 66). Demographic characteristics, history, outcomes, and laboratory tests, including CYFRA 21-1 levels, were collected and compared among the groups. Risk factors associated with the diagnosis of COVID-19 pneumonia and severity were explored using appropriate statistical methods. Results: CYFRA 21-1 levels progressively increased from mild non–COVID-19 CAP to mild COVID-19 and severe COVID-19. Lower lymphocyte and platelet counts, alongside elevated CYFRA 21-1 levels, were associated with COVID-19 pneumonia. Multivariate analysis identified CYFRA 21-1 as an independent diagnostic [diagnosis odds ratio (OR) = 2.369; 95% confidence interval (CI) = 1.638–3.605; p < 0.001] and prognosis factor of COVID-19 pneumonia (severity OR = 1.416; 95% CI = 1.119–1.867; p = 0.01). The area under the receiver operating characteristic curve of CYFRA 21-1 for predicting the development of severe COVID-19 pneumonia was 0.913. Spearman analysis showed a negative correlation between CYFRA 21-1 levels and oxygenation index, with a correlation coefficient of −0.278 (p = 0.024). Conclusion: CYFRA 21-1 may be a potential diagnostic and prognostic indicator of COVID-19 pneumonia. Prospective multicenter studies are needed to confirm its clinical value.
Text
fpubh-13-1738947 (2)
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Accepted/In Press date: 3 December 2025
Published date: 18 December 2025
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Copyright © 2025 Shen, Wu, Xie, He, Wang and Lv.
Keywords:
COVID-19, CYFRA 21-1, cancer biomarkers, risk stratification, viral pneumonia
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Local EPrints ID: 508225
URI: http://eprints.soton.ac.uk/id/eprint/508225
ISSN: 2296-2565
PURE UUID: f6a4833c-28b2-4b48-bcbf-6299fde0c175
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Date deposited: 14 Jan 2026 18:07
Last modified: 17 Jan 2026 03:04
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Author:
Simei Shen
Author:
Dandan Wu
Author:
Haiqin Xie
Author:
Haiyan He
Author:
Xuedong Lv
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