Correlation of interleukin-6 with Epstein–Barr virus levels in COVID-19

© The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat iveco mmons .org/licen ses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creat iveco mmons .org/publi cdoma in/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Introduction Severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) causes coronavirus disease 2019 (COVID-19) pneumonia with respiratory failure in a subset of infected patients. To date, it is unclear which factors trigger or cause the severe course of disease. Moreover, there is only limited evidence concerning extrapulmonary manifestations of COVID-19. We observed that COVID-19 patients invasively ventilated in our intensive care unit (ICU) showed biochemical abnormalities that resemble hepatitis and pancreatitis typically caused by herpesviruses like Epstein–Barr virus (EBV) or cytomegalia virus (CMV). Moreover, a subgroup of COVID-19 patients exhibit a hyperinflammatory pattern similar to secondary hemophagocytic lymphohistiocytosis (sHLH) [1, 2], a syndrome that can be triggered by viruses like EBV. Thus, we speculated whether critically ill COVID-19 patients show evidence of EBVor CMV-infection or reactivation and quantified EBV as well as CMV DNA levels in blood by PCR. Case series Herein, we report a retrospective analysis using data of the Tyrolean COVID-19 intensive care registry. We evaluated all COVID-19 patients that were treated between March 26, 2020, and April 20, 2020, in the Medical ICU at the Medical University Innsbruck, Austria, due to respiratory failure and required invasive ventilation (n = 20). Eighteen patients had at least one EBV and CMV PCR during ICU stay and were thus eligible for analysis. They were compared to eighteen consecutive invasively ventilated ICU patients without COVID-19. We found that 78% of COVID-19 patients had EBV viremia, 39% even above 1000 IU/ml. Prevalence and levels of EBV viremia were significantly higher in COVID19 patients compared to non-COVID-19 patients (44.4%, Pearson Chi-square p = 0.040, Mann–Whitney U test p = 0.022, SPSS 26 (IBM, Armonk, NY)). In contrast, only 17% of COVID-19 patients and 5.6% of non-COVID-19 patients had evidence of CMV viremia, which was not significantly different between the groups (Pearson Chi-square p = 0.289). No correlations between viral load of EBV and blood levels of hepatic and pancreatic enzymes or cholestasis parameters were detected. However, there was a significant correlation between EBV viremia and interleukin-6 (IL-6) level (Fig. 1, r = 0.621, p = 0.006) in COVID-19 patients, but not in non-COVID-19 patients (r = − 0.195, p = 0.438, Spearman’s rank-order correlation). Detailed patient characteristics are outlined in Table 1. Open Access


Introduction
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) pneumonia with respiratory failure in a subset of infected patients. To date, it is unclear which factors trigger or cause the severe course of disease. Moreover, there is only limited evidence concerning extrapulmonary manifestations of COVID-19.
We observed that COVID-19 patients invasively ventilated in our intensive care unit (ICU) showed biochemical abnormalities that resemble hepatitis and pancreatitis typically caused by herpesviruses like Epstein-Barr virus (EBV) or cytomegalia virus (CMV). Moreover, a subgroup of COVID-19 patients exhibit a hyperinflammatory pattern similar to secondary hemophagocytic lymphohistiocytosis (sHLH) [1,2], a syndrome that can be triggered by viruses like EBV.
Thus, we speculated whether critically ill COVID-19 patients show evidence of EBV-or CMV-infection or reactivation and quantified EBV as well as CMV DNA levels in blood by PCR.

Case series
Herein, we report a retrospective analysis using data of the Tyrolean COVID-19 intensive care registry. We evaluated all COVID-19 patients that were treated between March 26, 2020, and April 20, 2020, in the Medical ICU at the Medical University Innsbruck, Austria, due to respiratory failure and required invasive ventilation (n = 20). Eighteen patients had at least one EBV and CMV PCR during ICU stay and were thus eligible for analysis. They were compared to eighteen consecutive invasively ventilated ICU patients without COVID-19.
In contrast, only 17% of COVID-19 patients and 5.6% of non-COVID-19 patients had evidence of CMV viremia, which was not significantly different between the groups (Pearson Chi-square p = 0.289). No correlations between viral load of EBV and blood levels of hepatic and pancreatic enzymes or cholestasis parameters were detected.

Discussion
This is the first systematic report of EBV viremia in critically ill COVID-19 patients which revealed two important findings: First, COVID-19 patients have a higher prevalence of EBV viremia compared to non-COVID-19 patients. Second, levels of EBV viremia correlate with IL-6 in COVID-19 patients but not in non-COVID-19 patients.
Since EBV can induce immune dysregulation and expression of IL-6 in peripheral blood mononuclear cells (PBMCs) via deoxyuridine triphosphate nucleotidohydrolase (dUTPase) in vitro [3], one might speculate that EBV acts as an additional inflammatory trigger in critically ill COVID-19 patients.
The observation that two patients without history of allergy but an EBV viremia above 1000 IU/ml developed a generalized maculopapular rash following administration of amoxicillin/clavulanate and piperacillin/tazobactam, further emphasizes the hypothesized immunological impact of EBV in this setting [4,5].
Although this observation was made in a limited number of patients in a retrospective analysis, the systematic approach based on registry data minimizes the risk of selection bias. Moreover, we compared COVID-19 patients to an appropriate control group. The findings concerning EBV and CMV viremia in the control group are in accordance with previously reported cumulative incidences (i.e., 48% and 18%, respectively) [6].

Conclusion
These data suggest that EBV viremia is highly prevalent in COVID-19 patients with respiratory failure and associated with systemic inflammation as evidenced by high IL-6 levels. It remains to be elucidated whether EBV