Clinical characteristics of COVID-19 patients.

Objectives
To study the role of biological markers of immunothrombosis and polymorphisms of cytokine genes IL2, IL6, IL10 and their influence on the severity of COVID-19 in a Kazakh population.
Methods
A total of 301 patients of Kazakh nationality with a confirmed diagnosis of COVID-19 participated in the retrospective study, including 142 patients with severe and 159 with a mild course. Single nucleotide polymorphisms IL2R rs1801274, IL6 rs2069840, and IL10 rs1800872 were genotyped by real-time PCR. Activated partial thromboplastin time, normalized ratio, prothrombin index, prothrombin time, fibrinogen prothrombin time, fibrinogen, D-dimer, and C-reactive protein analysis were also conducted.
Results
The average age of patients with severe COVID-19 is higher than of patients with mild COVID-19 (p = 0.03). The findings showed that fibrinogen, D-dimer, and C-reactive protein were significantly greater in the group of patients with severe COVID-19 (p = 0.0001). A very strong correlation between the severity of COVID-19 with the D-dimer and C-reactive protein (p = 0.9) (p = 0.02) was found.
Conclusion
The results of our study confirm that D-dimer, fibrinogen, and CRP are biomarkers of inflammation and hypercoagulation that serve as predictors of immunothrombosis affecting the severity of COVID-19. D-dimer is also associated with IL10 rs1800872 gene polymorphism in the Kazakh population with severe COVID-19.