Reduced IFN-γ levels along with changes in hematologic and immunologic parameters are key to COVID-19 severity in Bangladeshi patients.

• Interleukin (IL)-4 and IL-6 levels along with erythrocyte sedimentation rate (ESR); neutrophil count; and the levels of ferritin, C-reactive protein (CRP), and D-dimer were significantly increased however, interferon (IFN)-γ levels were significantly reduced in patients with severe coronavirus disease 2019 (COVID-19) compared with those in patients with mild and/or moderate COVID-19. • The white blood cell (WBC), lymphocyte, eosinophil, and platelet counts are significantly reduced in patients with severe COVID-19 in comparison with those in patients with mild and moderate COVID-19 symptoms. • The neutrophil-to-lymphocyte ratio (NLR), IL-6-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and ferritin-to-ESR ratio are also significantly higher in patients with severe COVID-19 than in those with mild and/or moderate COVID-19. • The reduced level of IFN-γ is attributed to a less fatality toll in Bangladesh. The manifestation of coronavirus disease 2019 (COVID-19) severity and mortality has been associated with dysregulation of the immune response, often influenced by racial disparities and conferred by changes in hematologic and immunologic parameters. These biological and hematologic parameters as well as cytokine profiles were investigated in a cohort of 61 COVID-19-positive patients (categorized into mild, moderate, and severe groups) from Bangladesh using standard analytical methods. The data reported that the interleukin (IL)-4 and IL-6 levels were significantly increased, whereas the levels of interferon (IFN)-γ were significantly reduced in patients with severe COVID-19 (p < 0.05) compared with those in patients with mild and/or moderate COVID-19. The extent of erythrocyte sedimentation rate (ESR); neutrophil count; and levels of ferritin, C-reactive protein (CRP), and D-dimer (p < 0.05) were found to be significantly increased, whereas the white blood cell (WBC), lymphocyte, eosinophil, and platelet counts (p < 0.05) were observed to be significantly reduced in patients with severe COVID-19 compared with those in the patients in other 2 groups. Our study exhibited a significantly higher IL-6-to-lymphocyte ratio in patients with severe COVID-19 than in those with mild and moderate COVID-19. The calculated neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and ferritin-to-ESR ratio were significantly increased in patients with severe COVID-19. The increase in the IL-4 and IL-6 levels along with CRP and D-dimer levels may envisage a hyperinflammatory environment and immune dysregulation, which contribute to prolonged viral persistence, leading to severe disease. However, the reduced level of IFN-γ can be attributed to a less fatality toll in Bangladesh compared with that in the rest of the world. [ABSTRACT FROM AUTHOR]