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. 2020 Jul 9;5(13):e139024.
doi: 10.1172/jci.insight.139024.

IL-6 and CD8+ T cell counts combined are an early predictor of in-hospital mortality of patients with COVID-19

Miao Luo  1 , Jing Liu  2 , Weiling Jiang  1 , Shuang Yue  1 , Huiguo Liu  1 , Shuang Wei  1
Affiliations

IL-6 and CD8+ T cell counts combined are an early predictor of in-hospital mortality of patients with COVID-19

Miao Luo et al. JCI Insight. .

Abstract

BACKGROUNDFatal cases of COVID-19 are increasing globally. We retrospectively investigated the potential of immunologic parameters as early predictors of COVID-19.METHODSA total of 1018 patients with confirmed COVID-19 were enrolled in our 2-center retrospective study. Clinical feature, laboratory test, immunological test, radiological findings, and outcomes data were collected. Univariate and multivariable logistic regression analyses were performed to evaluate factors associated with in-hospital mortality. Receiver operator characteristic (ROC) curves and survival curves were plotted to evaluate their clinical utility.RESULTSThe counts of all T lymphocyte subsets were markedly lower in nonsurvivors than in survivors, especially CD8+ T cells. Among all tested cytokines, IL-6 was elevated most significantly, with an upward trend of more than 10-fold. Using multivariate logistic regression analysis, IL-6 levels of more than 20 pg/mL and CD8+ T cell counts of less than 165 cells/μL were found to be associated with in-hospital mortality after adjusting for confounding factors. Groups with IL-6 levels of more than 20 pg/mL and CD8+ T cell counts of less than 165 cells/μL had a higher percentage of older and male patients as well as a higher proportion of patients with comorbidities, ventilation, intensive care unit admission, shock, and death. Furthermore, the receiver operating curve of the model combining IL-6 (>20 pg/mL) and CD8+ T cell counts (<165 cells/μL) displayed a more favorable discrimination than that of the CURB-65 score. The Hosmer-Lemeshow test showed a good fit of the model, with no statistical significance.CONCLUSIONIL-6 (>20 pg/mL) and CD8+ T cell counts (<165 cells/μL) are 2 reliable prognostic indicators that accurately stratify patients into risk categories and predict COVID-19 mortality.FundingThis work was supported by funding from the National Natural Science Foundation of China (no. 81772477 and 81201848).

Keywords: Cytokines; Infectious disease; Pulmonology; T cells.

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Conflict of interest statement

Conflict of interest: The authors have declared that no conflict of interest exists.

Figures

Figure 1
Figure 1. ROC curves of T lymphocyte subsets and cytokines.
(A) ROC curves of each category of T lymphocyte subgroup. (B) ROC curves for each category of serum cytokines. AUC, area under the ROC curve; ROC, receiver operating characteristic.
Figure 2
Figure 2. Correlation analysis of indicators of patients with COVID-19.
(A) Correlation analysis between plasma IL-6 and CRP levels (R2 = 0.424, P < 0.001). (B) Correlation analysis between plasma IL-6 levels and CD8+ T cell counts (R2 = 0. 255, P < 0.001). (C) Correlation analysis between plasma CRP levels and CD8+ T cell counts (R2 = 0. 294, P < 0.001). IL-6, C-reactive protein (CRP), and CD8+ T cell counts were collected on admission.
Figure 3
Figure 3. Kaplan-Meier survival curves in 4 groups of patients with COVID-19.
The survival rates of groups I–IV were 98.8% (481 of 487), 77.6% (76 of 98), 85.7% (174 of 203), and 37.4% (86 of 230) at the observed endpoint during hospitalization, respectively. Compared with group I, the patients from the other 3 groups had worse survival rates (P < 0.001). The patients from group IV had a much shorter survival time than those from groups II or III (P < 0.001). However, there was no statistical difference between groups II and III (P = 0.205). Group I, IL-6 ≤20 pg/mL and CD8+ T cells ≥165 cells/μL, n = 487; group II, IL-6 >20 pg/mL and CD8+ T cells ≥165 cells/μL, n = 98; group III, IL-6 ≤20 pg/mL and CD8+ T cells <165 cells/μL, n = 203; and group IV, IL-6 >20 pg/mL and CD8+ T cells <165 cells/μL, n = 230.
Figure 4
Figure 4. ROC curve analysis to predict in-hospital mortality in patients with COVID-19.
ROC curves derived from the model of combined elevated IL-6 and reduced CD8+ T cell counts and CURB-65 scores in our cohort. The ROC curves of this predictive model showed a better performance than that of the CURB-65 score (P < 0.001).
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References

    1. Huang C, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020;395(10223):497–506. doi: 10.1016/S0140-6736(20)30183-5. - DOI - PMC - PubMed
    1. Chen G, et al. Clinical and immunological features of severe and moderate coronavirus disease 2019. J Clin Invest. 2020;130(5):2620–2629. doi: 10.1172/JCI137244. - DOI - PMC - PubMed
    1. Chen L, et al. [Analysis of clinical features of 29 patients with 2019 novel coronavirus pneumonia] Zhonghua Jie He He Hu Xi Za Zhi. 2020;43(3):203–208. - PubMed
    1. Ruan Q, Yang K, Wang W, Jiang L, Song J. Clinical predictors of mortality due to COVID-19 based on an analysis of data of 150 patients from Wuhan, China. Intensive Care Med. 2020;46(5):846–848. doi: 10.1007/s00134-020-05991-x. - DOI - PMC - PubMed
    1. Wan S, et al. Relationships among lymphocyte subsets, cytokines, and the pulmonary inflammation index in coronavirus (COVID-19) infected patients. Br J Haematol. 2020;189(3):428–437. doi: 10.1111/bjh.16659. - DOI - PMC - PubMed

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