No abstract

Background A subset of patients with severe COVID-19 develop a hyperinflammatory syndrome, which might contribute to morbidity and mortality. This study explores a specific phenotype of COVID-19-associated hyperinflammation (COV-HI), and its associations with escalation of respiratory support and survival. Methods In this retrospective cohort study, we enrolled consecutive inpatients (aged ≥18 years) admitted to University College London Hospitals and Newcastle upon Tyne Hospitals in the UK with PCR-confirmed COVID-19 during the first wave of community-acquired infection. Demographic data, laboratory tests, and clinical status were recorded from the day of admission until death or discharge, with a minimum follow-up time of 28 days. We defined COV-HI as a C-reactive protein concentration greater than 150 mg/L or doubling within 24 h from greater than 50 mg/L, or a ferritin concentration greater than 1500 μg/L. Respiratory support was categorised as oxygen only, non-invasive ventilation, and intubation. Initial and repeated measures of hyperinflammation were evaluated in relation to the next-day risk of death or need for escalation of respiratory support (as a combined endpoint), using a multi-level logistic regression model. Findings We included 269 patients admitted to one of the study hospitals between March 1 and March 31, 2020, among whom 178 (66%) were eligible for escalation of respiratory support and 91 (34%) patients were not eligible. Of the whole cohort, 90 (33%) patients met the COV-HI criteria at admission. Despite having a younger median age and lower median Charlson Comorbidity Index scores, a higher proportion of patients with COV-HI on admission died during follow-up (36 [40%] of 90 patients) compared with the patients without COV-HI on admission (46 [26%] of 179). Among the 178 patients who were eligible for full respiratory support, 65 (37%) met the definition for COV-HI at admission, and 67 (74%) of the 90 patients whose respiratory care was escalated met the criteria by the day of escalation. Meeting the COV-HI criteria was significantly associated with the risk of next-day escalation of respiratory support or death (hazard ratio 2·24 [95% CI 1·62–2·87]) after adjustment for age, sex, and comorbidity. Interpretation Associations between elevated inflammatory markers, escalation of respiratory support, and survival in people with COVID-19 indicate the existence of a high-risk inflammatory phenotype. COV-HI might be useful to stratify patient groups in trial design. Funding None.

What is known?The NEWS2 scoring system is widely used throughout the UK NHS to monitor physiological parameters in order to enable the early detection of clinical deterioration. However, its performance in COVID-19 has not been validated and concerns have been raised about its sensitivity. What is the question?We aimed to ascertain whether longitudinal NEWS2 monitoring can pre-emptively identify clinical deterioration in patients hospitalised with COVID-19. What was found?NEWS2 ≥5 had an excellent sensitivity to detect deteriorating COVID-19 patients, albeit at the expense of a relatively high false-trigger rate. Longitudinal trends in NEWS2 scores increased many hours before serious clinical events, and baseline NEWS2 was also modestly predictive of future clinical deterioration. What is the implication for practice now?NEWS2 monitoring is an appropriately sensitive method for identifying the potential for clinical deterioration of hospitalised COVID-19 patients and should continue to be used alongside clinical judgement.

The homeostatic maintenance of normal numbers of mature T lymphocytes in the immune system depends on signaling from the T cell antigen receptor (TCR) and the interleukin-7 receptor (IL-7R); however, it is unclear whether there is crosstalk between these two receptors. Here, we have identified a central role for TCR signaling during the development of T lymphocytes in the thymus in the determination of IL-7 function in mature T lymphocytes. We showed that Il7r expression in mature T cells was modulated by developmental TCR-dependent signals elicited during the process of positive selection in the thymus and that this mechanism was common to both CD4(+) and CD8(+) T cells. Control of Il7r expression by the TCR was limited to thymocytes because neither the abundance nor the function of IL-7Rα was affected by TCR signaling in peripheral T cells. Finally, we showed that thymocytes without optimal IL-7Rα abundance failed to form part of the pool of mature T lymphocytes that patrol the periphery of normal hosts, highlighting the importance of this mechanism in shaping the repertoire of lymphocytes that make up this population.