The Impact of COVID-19 on White Blood Cell Subpopulations and Inflammatory Markers

Background: COVID-19 is a disease of the zoonosis class and much has come to light since the onset of the pandemic in December 2019. Understanding COVID-19 pathophysiology is crucial for its effective treatment. The present study is conducted to observe the haematological changes associated with COVID-19 infection among a cohort of Iraqi patients. Methods and Design: A retrospective cohort study involving confirmed (60) COVID-19 patients and (20) individuals in the control group admitted to Al Karama Teaching Hospital in Al-Kut Wasit Province, Iraq. Data captured included complete blood counts (CBC), C-reactive protein (CRP), and D-dimer levels. The statistical analysis covered t-tests for between-group comparison and multiple linear regression to ascertain the associations between the haematological parameters. Results: The COVID-19 patients had a significantly higher total white blood cell count, with a mean of 17.1575 than the control groups of 8.7005 (p > 0.001). COVID-19 patients also had significantly greater mean lymphocyte counts (mean 55.365) compared to controls (mean 29.79; p > 0.001), suggesting the presence of lymphocytosis. The COVID-19 patients also showed significantly higher mean neutrophil count (mean 82.9205) than the control group (mean 60.369; p > 0. The mean levels of CRP were 75.74667 in COVID-19 patients, which is significantly higher compared to 3.11 as observed in the control group (p > 0.001). Similarly, the mean D-dimer levels were higher in COVID-19 patients at 2319.7 compared to 336.65 in the control group (p > 0.001). The correlation analysis shows a high negative correlation between WBCs and neutrophils and a moderate positive correlation between CRP and D-dimer, which reflects the complex interplay between inflammatory and coagulation processes. Conclusion: This study highlights striking haematological changes in COVID-19, characterized by lymphocytosis, neutrophilia, and activation of inflammatory and coagulation markers. It underlines the importance of monitoring these parameters for better patient management. More research is needed to explore therapeutic interventions targeting these specific immune and coagulation responses in COVID-19.