Peripheral White Blood Cell Dynamics as a Biomarker of Coronavirus Disease Severity
- Author:
Joung Ha PARK
1
;
Joung Ha PARK
;
Hyemin CHUNG
;
Hyemin CHUNG
;
Min-Chul KIM
;
Min-Chul KIM
;
Seong-Ho CHOI
;
Seong-Ho CHOI
;
Jin-Won CHUNG
;
Jin-Won CHUNG
;
Hye Ryoun KIM
;
Hye Ryoun KIM
Author Information
- Publication Type:Original Article
- From:Annals of Laboratory Medicine 2026;46(3):289-296
- CountryRepublic of Korea
- Language:English
-
Abstract:
Background:Despite widespread vaccination efforts against severe acute respiratory syndrome coronavirus 2, variants with increased transmissibility or immune evasion continue to emerge, posing a considerable challenge. Understanding the immunological factors associated with coronavirus disease (COVID-19) progression is essential for improving patient management and treatment strategies. We explored the dynamic changes in the peripheral white blood cell (WBC) profile, including T lymphocyte subsets, to assess their potential as predictors of disease severity and progression.
Methods:Two hundred fifty-eight patients hospitalized for confirmed COVID-19 were classified into four sub-cohorts based on changes in disease severity over 7 days. WBC parameters, including absolute neutrophil, total lymphocyte, and T cell subset counts, and the neutrophil-to-lymphocyte ratio (NLR) were assessed at admission and after 7 days.
Results:Patients with persistent mild-to-moderate illness exhibited a marked increase in the lymphocyte count and a decrease in the NLR over time. In contrast, patients with sustained severe-to-critical illness showed an increasing WBC count without a corresponding increase in the lymphocyte count, in addition to a marked elevation in the NLR. Patients whose condition improved from severe-to-critical to mild-to-moderate illness showed increased cluster of differentiation (CD)3+ and CD4+ T cell counts and an elevated CD4/CD8 ratio, whereas the NLR did not significantly change.
Conclusions:The early-phase dynamics of T cell subsets may serve as a useful biomarker of disease severity and recovery in patients with COVID-19. Monitoring these immunological changes may help support clinical decision-making and inform the timing of therapeutic interventions.
