analysis of immune profiles related to disease severity in covid-19 by flow cytometry

Background: more than 768 million people have been affected by covid-19. identifying lymphocyte subsets and cytokine level abnormalities in covid-19 patients is essential to gain new insights and data on immunity mechanisms against viral infections. objectives: we used flow cytometry to determine the relationship between disease severity, lymphocyte subsets distribution, and cytokine level alterations in covid-19 patients. methods: totally 94 covid-19 patients (32 mild, 31 moderate, and 31 severe) and 27 healthy individuals were included in the cross-sectional study. the distribution of peripheral lymphocyte subsets and cytokine levels was assessed by flow cytometry. results: the percentages of cd56+ natural killer (nk) cells in all patient groups and total t lymphocytes in moderate and severe groups were significantly lower than those in the control group (p < 0.001). also, il-2 (p < 0.001), il-17a (p < 0.001), il-4 (p < 0.001), il-6 (p < 0.001), tnf-α (p = 0.004), ip-10 (p < 0.001), ifn-λ1 (il-29) (p < 0.001), ifn-λ2/3 (il-28a/b) (p = 0.011), ifn-β (p < 0.001), il-10 (p < 0.001), and ifn-γ (p < 0.001) levels were statistically higher in patients than in the controls. conclusions: our data revealed that increased levels of certain cytokines in peripheral blood contribute to disease severity. increased crp (or: 1.012, %95 ci: 1.002 - 1.023, p = 0.038) and il-10 (or: 1.068, %95 ci: 1.000 - 1.141, p = 0.049) levels, decreased cd56+ nk percentage (or: 0.576, %95 ci: 0.376 - 0.882, p = 0.011) and lymphocyte count (or: 0.02, %95 ci: 0.001 - 0.368, p = 0.009), and the presence of diabetes mellitus and mechanical ventilation were independent predictors of mortality.