ObjectivesTo study the role of biological markers of immunothrombosis and polymorphisms of cytokine genesIL2,IL6,IL10and their influence on the severity of COVID-19 in a Kazakh population.MethodsA 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 polymorphismsIL2Rrs1801274,IL6rs2069840, andIL10rs1800872 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.ResultsThe 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.ConclusionThe 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 withIL10rs1800872 gene polymorphism in the Kazakh population with severe COVID-19.