Dissecting CD8+ T cell pathology of severe SARS-CoV-2 infection by single-cell epitope mapping

The current COVID-19 pandemic represents a global challenge. A better understanding of the immune response against SARS-CoV-2 is key to unveil the differences in disease severity and to develop future vaccines targeting novel SARS-CoV-2 variants. Feature barcode technology combined with CITE-seq antibodies and DNA-barcoded peptide-MHC I Dextramer reagents enabled us to identify relevant SARS-CoV-2-derived epitopes and compare epitope-specific CD8+ T cell populations between mild and severe COVID-19. We identified a strong CD8+ T cell response against an S protein-derived epitope. CD8+ effector cells in severe COVID-19 displayed hyperactivation, T cell exhaustion and were missing characteristics of long-lived memory T cells. We identify A*0101 WTAGAAAYY as an immunogenic CD8+ T cell epitope with the ability to drive clonal expansion. We provide an in-depth characterization of the CD8+ T cell-mediated response to SARS-CoV-2 infection which will be relevant for the development of molecular and targeted therapies and potential adjustments of vaccination strategies.

Biometric covariates and outcome in COVID-19 patients: Are we looking close enough?

BackgroundThe impact of biometric covariates on risk for adverse outcomes of COVID-19 disease was assessed by numerous observational studies on unstratified cohorts, which show great heterogeneity. However, multilevel evaluations to find possible complex, e. g. non-monotonic multi-variate patterns reflecting mutual interference of parameters are missing. We used a more detailed, computational analysis to investigate the influence of biometric differences on mortality and disease evolution among severely ill COVID-19 patients. MethodsWe analyzed a group of COVID-19 patients requiring Intensive care unit (ICU) treatment. For further analysis, the study group was segmented into six subgroups according to BMI and age. To link the BMI/age derived subgroups with risk factors, we performed an enrichment analysis of diagnostic parameters and comorbidities. To suppress spurious patterns, multiple segmentations were analyzed and integrated into a consensus score for each analysis step. ResultsWe analyzed 81 COVID-19 patients, of whom 67 required MV. Mean mortality was 35.8 %. We found a complex, non-monotonic interaction between age, BMI and mortality. A subcohort of patients with younger age and intermediate BMI exhibited a strongly reduced mortality risk (p < 0.001), while differences in all other groups were not significant. Univariate impacts of BMI or age on mortality were missing. Comparing MV with non-MV patients, we found an enrichment of baseline CRP, PCT and D-Dimers within the MV-group, but not when comparing survivors vs. non-survivors within the MV patient group. ConclusionsThe aim of this study was to get a more detailed insight into the influence of biometric covariates on the outcome of COVID-19 patients with high degree of severity. We found that survival in MV is affected by complex interactions of covariates differing to the reported covariates, which are hidden in generic, non-stratified studies on risk factors. Hence, our study suggests that a detailed, multivariate pattern analysis on larger patient cohorts reflecting the specific disease stages might reveal more specific patterns of risk factors supporting individually adapted treatment strategies.

Ivabradine for the Therapy of Chronic Stable Angina Pectoris: a Systematic Review and Meta-Analysis

Background and Objectives@#Coronary artery disease (CAD) is the number one cause of death worldwide. The If channel inhibitor ivabradine serves as second line medication for the CAD leading symptom angina pectoris. This systematic review and meta-analysis assess the existing evidence of ivabradine in angina pectoris. @*Methods@#We systematically searched MEDLINE, Embase, CENTRAL, and Web of Science (September 2019) for randomized controlled trials (RCTs) that compared ivabradine versus placebo, standard therapy (ST) or other anti-anginal drugs. Two review authors independently assessed trials for inclusion and performed data extraction. We completed a ‘risk of bias’ assessment for all studies and assessed quality of the trial evidence using the Grading of Recommendations Assessment, Development and Evaluation methodology. We meta-analysed data were applicable and calculated mean differences (MDs) and risk ratios using a random-effects model. @*Results@#A total of 11 RCTs (n=16,039) were included. Compared to placebo/ST, we found significant effects on the frequency of hospitalisation in a small cohort (n=90; hazard ratio [HR], 0.19; 95% confidence interval [CI], 0.04, −0.92; p=0.04), but no effects on cardiovascular mortality (n=19,102; HR, 1.10; 95% CI, 0.94, 1.28; p=0.25) or the frequency of angina pectoris episodes (n=167; weighted MD, −1.06; 95% CI, −2.74, −0.61; p=0.21). @*Conclusions@#The present work makes an important contribution to optimal patient care in angina pectoris by complementing the current European Society of Cardiology guideline—recommending class IIa with evidence level B—decisively with 8 further studies.

Interleukin-6 Serum Levels Correlate With Severity of Burn Injury but Not With Gender.

Gender-specific differences in the outcome of patients with burn injury have been recognized in the past with female patients being at a higher risk of mortality. We hypothesized that early post-burn interleukin-6 (IL-6) cytokine levels may contribute to the different gender-specific outcome. We retrospectively examined 94 burned patients who were treated in the Burn Intensive Care Unit at the University Hospital Aachen. Age, gender, presence of inhalation injury, depth, TBSA, and clinical outcome were documented. Serum samples for IL-6 analysis were collected within 24 hours posttrauma. The relationship between IL-6 levels, gender, survival, and abbreviated burn severity index score was investigated. Male patients (64.9%; n = 61) presented a higher median TBSA (26%) than female patients (20%). The mortality rate of male patients (27.9%; n = 17) and female patients (21.2%; n = 7) was similar. Deceased patients had significant higher TBSA (P = 0.0005) and IL-6 levels (P = 0.0007) than burn survivors. A moderate correlation between IL-6 levels and abbreviated burn severity index score was observed (r = 0.554; P < 0.0001). While TBSA showed a significant influence on IL-6 levels (P = 0.0003), gender did not (P = 0.7395) and inhalation injury indicated a minor influence (P = 0.0780). Only TBSA and age presented a significant influence on mortality (P = 0.0028 and P = 0.0031, respectively). All patients with burn trauma were characterized by elevated IL-6 levels with higher TBSA values resulting in more pronounced levels. Deceased patients had higher initial IL-6 serum levels reflecting higher TBSA and severity. In contrast to other defined trauma mechanisms, gender had no significant influence on postburn IL-6 serum levels and mortality in our patient population.