High Levels of Circulating IL-8 and Soluble IL-2R Are Associated With Prolonged Illness in Patients With Severe COVID-19.

Objectives: The coordinated immune response of the host is the key of the successful combat of the body against SARS-CoV-2 infection and is decisive for the development and progression of COVID-19. In this study, we aimed to investigate whether the immunological phenotype of patients are associated with duration of illness in patients with severe COVID-19. Method: In this single-center study, 69 patients with severe or critical COVID-19 were recruited retrospectively. Immunological parameters including counts of white blood cells, neutrophils, lymphocytes, the neutrophil-to-lymphocyte ratio, and levels of circulating cytokines and cytokine receptors were screened for their association with disease severity, survival and duration of illness of COVID-19. Results: Our data confirmed previous results that neutrophil-to-lymphocyte ratio and circulating levels of IL-6 represent prominent biomarker for the prediction of disease severity and survival of COVID-19. However, this study shows for the first time that duration of illness in patients with severe COVID-19 is positively associated with serum levels of IL-8 (P=0.004) and soluble IL-2Rα (P=0.025). Conclusion: The significant association of duration of illness with circulating levels of IL-8 and soluble IL-2Rα in patients with severe COVID-19 implicates that neutrophils and T cells are involved in the evolution of COVID-19.

A retrospective matched cohort single-center study evaluating outcomes of COVID-19 and the impact of immunomodulation on COVID-19-related cytokine release syndrome in solid organ transplant recipients.

This retrospective matched cohort study describes 30 solid organ transplant (SOT) patients with Coronavirus Disease 2019 (COVID-19) matched 1:2 to 60 non-SOT patients (control group) based on age, body mass index (BMI), and comorbidities (hypertension and diabetes mellitus with hemoglobin A1c > 8.0%). The SOT group had a higher proportion of cardiovascular disease (P < .05). During the index hospitalization, there were no significant differences with regard to disease severity or critical care needs (mechanical intubation, vasopressors, and renal replacement therapy). At 28 days, 4 (13%) patients died in the SOT group and 8 (13%) patients died in the control group (P = 1.0). Nineteen patients received tocilizumab in the SOT group compared to 29 patients in the control group. Among these patients, interleukin-6 (IL-6) and soluble interleukin-2 receptor (sIL2R) levels increased after tocilizumab and interleukin-10 (IL-10) levels decreased after tocilizumab. Overall, SOT patients had comparable mortality to non-SOT patients, although numerically more SOT patients received tocilizumab (63% vs 48%) and steroids (37% vs 20%). Larger, multi-center studies are needed to ascertain these findings. Lastly, the complex cytokine release syndrome in COVID-19 remains an area of intense research and the analysis of key interleukin levels (IL-6, IL-10, and sIL2R) in this study contributes to the understanding of this process.

Deciphering the COVID-19 cytokine storm: Systematic review and meta-analysis.

INTRODUCTION: The coronavirus pandemic has affected more than 20 million people so far. Elevated cytokines and suppressed immune responses have been hypothesized to set off a cytokine storm, contributing to ARDS, multiple-organ failure and, in the most severe cases, death. We aimed to quantify the differences in the circulating levels of major inflammatory and immunological markers between severe and nonsevere COVID-19 patients. METHODS: Relevant studies were identified from PubMed, EMBASE, Web of Science, SCOPUS and preprint servers. Risk of bias was assessed for each study, using appropriate checklists. All studies were described qualitatively and a subset was included in the meta-analysis, using forest plots. RESULTS: Based on 23 studies, mean cytokine levels were significantly higher (IL-6: MD, 19.55 pg/mL; CI, 14.80, 24.30; IL-8: MD, 19.18 pg/mL; CI, 2.94, 35.43; IL-10: MD, 3.66 pg/mL; CI, 2.41, 4.92; IL-2R: MD, 521.36 U/mL; CI, 87.15, 955.57; and TNF-alpha: MD, 1.11 pg/mL; CI, 0.07, 2.15) and T-lymphocyte levels were significantly lower (CD4+ T cells: MD, -165.28 cells/µL; CI, -207.58, -122.97; CD8+ T cells: MD, -106.51 cells/µL; CI, -128.59, -84.43) among severe cases as compared to nonsevere ones. There was heterogeneity across studies due to small sample sizes and nonuniformity in outcome assessment and varied definitions of disease severity. The overall quality of studies was sub-optimal. CONCLUSION: Severe COVID-19 is characterized by significantly increased levels of pro-inflammatory cytokines and reduced T lymphocytes. Well-designed and adequately powered prospective studies are needed to amplify the current evidence and provide definitive answers to dilemmas regarding timing and type of anti-COVID-19 therapy particularly in severe patients.

Diagnosis of SARS-CoV-2 infection in the setting of the cytokine release syndrome.

INTRODUCTION: Coronavirus disease (COVID-19) can trigger a cytokine response storm (CRS) that is associated with high mortality but for which the underlying pathophysiology and diagnostics are not yet well characterized. This review provides an overview of the underlying immune profile of COVID-19-related CRS as well as laboratory markers for acute diagnosis and chronic follow-up of patients with SARS-CoV-2 and CRS. AREAS COVERED: Innate and acquired immune profiles in COVID-19-CRS, RNA-detection methods for SARS-CoV-2 in the setting of CRS including factors that affect assay performance, serology for SARS-CoV-2 in the setting of CRS, and other biomarkers for COVID-19 will be discussed. EXPERT OPINION: Studies support the implication of CRS in the pathogenesis, clinical severity and outcome of COVID-19 through the production of multiple inflammatory cytokines and chemokines from activated innate and adaptive immune cells. Although these inflammatory molecules, including IL-6, IL-2 R, IL-10, IP-10 and MCP-1, often correlate with disease severity as possible biomarkers, the pathogenic contributions of individual molecules and the therapeutic benefits of targeting them are yet to be demonstrated. Detection of SARS-CoV-2 RNA is the gold standard method for diagnosis of COVID-19 in the context of CRS but assay performance varies and is susceptible to false-negative results even as patients clinically deteriorate due to decreased viral shedding in the setting of CRS. Biomarkers including CRP, ferritin, D-dimer and procalcitonin may provide early clues about progression to CRS and help identify thrombotic and infectious complications of COVID-19.

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

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).