Immune responses of lung transplant recipients against SARS-CoV-2 and common respiratory coronaviruses: Evidence for pre-existing cross-reactive immunity

Humoral and cellular immune responses to SARS-CoV-2 and other coronaviruses in lung transplant recipients are unknown. We measured antibodies and T cell responses against the SARS-CoV-2 spike S2 and nucleocapsid antigens and spike antigens from common respiratory coronaviruses (229E, NL63, OC43, and HKU1) after vaccination or infection of LTxRs. 148 LTxRs from single center were included in this study: 98 after vaccination and 50 following SARS-CoV-2 infection. Antibodies were quantified by enzyme-linked immunosorbent assay. The frequency of T cells secreting IL2, IL4, IL10, IL17, TNFα, and IFNγ were enumerated by enzyme-linked immunospot assay. Our results have shown the development of antibodies to SARS-CoV-2 spike protein in infected LTxRs (39/50) and vaccinated LTxRs (52/98). Vaccinated LTxRs had higher number of T cells producing TNFα but less cells producing IFNγ than infected LTxRs in response to the nucleocapsid antigen and other coronavirus spike antigens. We didn't find correlation between the development of antibodies and cellular immune responses against the SARS-CoV-2 spike protein after vaccination. Instead, LTxRs have pre-existing cellular immunity to common respiratory coronaviruses, leading to cross-reactive immunity against SARS-CoV-2 which likely will provide protection against SARS-Cov-2 infection.

Renin-Angiotensin System Modulation With Synthetic Angiotensin (1-7) and Angiotensin II Type 1 Receptor-Biased Ligand in Adults With COVID-19: Two Randomized Clinical Trials

Importance

Preclinical models suggest dysregulation of the renin-angiotensin system (RAS) caused by SARS-CoV-2 infection may increase the relative activity of angiotensin II compared with angiotensin (1-7) and may be an important contributor to COVID-19 pathophysiology.

Objective

To evaluate the efficacy and safety of RAS modulation using 2 investigational RAS agents, TXA-127 (synthetic angiotensin [1-7]) and TRV-027 (an angiotensin II type 1 receptor-biased ligand), that are hypothesized to potentiate the action of angiotensin (1-7) and mitigate the action of the angiotensin II.

Design, Setting, and Participants

Two randomized clinical trials including adults hospitalized with acute COVID-19 and new-onset hypoxemia were conducted at 35 sites in the US between July 22, 2021, and April 20, 2022; last follow-up visit: July 26, 2022.

Interventions

A 0.5-mg/kg intravenous infusion of TXA-127 once daily for 5 days or placebo. A 12-mg/h continuous intravenous infusion of TRV-027 for 5 days or placebo.

Main Outcomes and Measures

The primary outcome was oxygen-free days, an ordinal outcome that classifies a patient's status at day 28 based on mortality and duration of supplemental oxygen use; an adjusted odds ratio (OR) greater than 1.0 indicated superiority of the RAS agent vs placebo. A key secondary outcome was 28-day all-cause mortality. Safety outcomes included allergic reaction, new kidney replacement therapy, and hypotension.

Results

Both trials met prespecified early stopping criteria for a low probability of efficacy. Of 343 patients in the TXA-127 trial (226 [65.9%] aged 31-64 years, 200 [58.3%] men, 225 [65.6%] White, and 274 [79.9%] not Hispanic), 170 received TXA-127 and 173 received placebo. Of 290 patients in the TRV-027 trial (199 [68.6%] aged 31-64 years, 168 [57.9%] men, 195 [67.2%] White, and 225 [77.6%] not Hispanic), 145 received TRV-027 and 145 received placebo. Compared with placebo, both TXA-127 (unadjusted mean difference, -2.3 [95% CrI, -4.8 to 0.2]; adjusted OR, 0.88 [95% CrI, 0.59 to 1.30]) and TRV-027 (unadjusted mean difference, -2.4 [95% CrI, -5.1 to 0.3]; adjusted OR, 0.74 [95% CrI, 0.48 to 1.13]) resulted in no difference in oxygen-free days. In the TXA-127 trial, 28-day all-cause mortality occurred in 22 of 163 patients (13.5%) in the TXA-127 group vs 22 of 166 patients (13.3%) in the placebo group (adjusted OR, 0.83 [95% CrI, 0.41 to 1.66]). In the TRV-027 trial, 28-day all-cause mortality occurred in 29 of 141 patients (20.6%) in the TRV-027 group vs 18 of 140 patients (12.9%) in the placebo group (adjusted OR, 1.52 [95% CrI, 0.75 to 3.08]). The frequency of the safety outcomes was similar with either TXA-127 or TRV-027 vs placebo.

Conclusions and Relevance

In adults with severe COVID-19, RAS modulation (TXA-127 or TRV-027) did not improve oxygen-free days vs placebo. These results do not support the hypotheses that pharmacological interventions that selectively block the angiotensin II type 1 receptor or increase angiotensin (1-7) improve outcomes for patients with severe COVID-19.

Trial Registration

ClinicalTrials.gov Identifier: NCT04924660.

Utility of COVID-19 antigen testing in the emergency department

BACKGROUND

The BinaxNOW coronavirus disease 2019 (COVID-19) Ag Card test (Abbott Diagnostics Scarborough, Inc.) is a lateral flow immunochromatographic point-of-care test for the qualitative detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein antigen. It provides results from nasal swabs in 15 minutes. Our purpose was to determine its sensitivity and specificity for a COVID-19 diagnosis.

METHODS

Eligible patients had symptoms of COVID-19 or suspected exposure. After consent, 2 nasal swabs were collected; 1 was tested using the Abbott RealTime SARS-CoV-2 (ie, the gold standard polymerase chain reaction test) and the second run on the BinaxNOW point of care platform by emergency department staff.

RESULTS

From July 20 to October 28, 2020, 767 patients were enrolled, of which 735 had evaluable samples. Their mean (SD) age was 46.8 (16.6) years, and 422 (57.4%) were women. A total of 623 (84.8%) patients had COVID-19 symptoms, most commonly shortness of breath (n = 404; 55.0%), cough (n = 314; 42.7%), and fever (n = 253; 34.4%). Although 460 (62.6%) had symptoms ≤7 days, the mean (SD) time since symptom onset was 8.1 (14.0) days. Positive tests occurred in 173 (23.5%) and 141 (19.2%) with the gold standard versus BinaxNOW test, respectively. Those with symptoms >2 weeks had a positive test rate roughly half of those with earlier presentations. In patients with symptoms ≤7 days, the sensitivity, specificity, and negative and positive predictive values for the BinaxNOW test were 84.6%, 98.5%, 94.9%, and 95.2%, respectively.

CONCLUSIONS

The BinaxNOW point-of-care test has good sensitivity and excellent specificity for the detection of COVID-19. We recommend using the BinasNOW for patients with symptoms up to 2 weeks.

Cutting Edge: Circulating Exosomes with COVID Spike Protein Are Induced by BNT162b2 (Pfizer-BioNTech) Vaccination prior to Development of Antibodies: A Novel Mechanism for Immune Activation by mRNA Vaccines

Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) causes severe acute respiratory syndrome. mRNA vaccines directed at the SARS-CoV-2 spike protein resulted in development of Abs and protective immunity. To determine the mechanism, we analyzed the kinetics of induction of circulating exosomes with SARS-CoV-2 spike protein and Ab following vaccination of healthy individuals. Results demonstrated induction of circulating exosomes expressing spike protein on day 14 after vaccination followed by Abs 14 d after the second dose. Exosomes with spike protein, Abs to SARS-CoV-2 spike, and T cells secreting IFN-γ and TNF-α increased following the booster dose. Transmission electron microscopy of exosomes also demonstrated spike protein Ags on their surface. Exosomes with spike protein and Abs decreased in parallel after four months. These results demonstrate an important role of circulating exosomes with spike protein for effective immunization following mRNA-based vaccination. This is further documented by induction of humoral and cellular immune responses in mice immunized with exosomes carrying spike protein.

The Internet Tracking Registry of Acute Coronary Syndromes (i*trACS): A Multicenter Registry of Patients With Suspicion of Acute Coronary Syndromes Reported Using the Standardized Reporting Guidelines for Emergency Department Chest Pain Studies

STUDY OBJECTIVE

Observational studies of well-described patient populations presenting to emergency departments (EDs) with suspicion of acute coronary syndrome are necessary to understand the relationships between patients' signs and symptoms, cardiac risk profile, test results, practice patterns, and outcomes. We describe the methods for data collection and the ED population enrolled in a multicenter registry of patients with chest pain.

METHODS

Patients older than 18 years, presenting to one of 8 EDs in the United States or 1 ED in Singapore, and with possible acute coronary syndrome were enrolled in the Internet Tracking Registry of Acute Coronary Syndromes between June 1999 and August 2001. Prospective data, including presenting signs and symptoms, ECG findings, and the ED physician's initial impression of risk, were systematically collected. Medical record review or daily follow-up was used to obtain cardiac biomarker results, invasive and noninvasive testing, treatments, procedures, and inhospital outcomes. Thirty-day outcomes were determined by telephone follow-up and medical record review.

RESULTS

The registry includes 15,608 patients, with 17,713 visits. Chest pain was the chief complaint in 71% of visits. The ECG was diagnostic of ischemia or infarction in 10.1% and positive cardiac biomarkers were observed in 10% of visits. Forty-three percent of patients were sent home directly from the ED. Of admitted patients, 5% died by 30 days, and 3% had documented coronary artery disease or had undergone percutaneous coronary intervention or coronary artery bypass grafting within 30 days. For patients discharged directly from the ED, 0.4% died or had a documented myocardial infarction within 30 days. Coronary artery bypass graft surgery, percutaneous coronary intervention, or a diagnosis of coronary artery disease was found in 0.5% of discharged patients.

CONCLUSION

A unique description of undifferentiated ED chest pain patients with suspected acute coronary syndrome is provided. The data set can be used to generate and explore hypotheses to improve understanding of the complex relationships between presentation, treatment, testing, intervention and outcomes.

The impact of race on the acute management of chest pain

OBJECTIVES

African Americans with acute coronary syndromes receive cardiac catheterization less frequently than whites. The objective was to determine if such disparities extend to acute evaluation and non interventional treatment.

METHODS

Data on adults with chest pain (N = 7,935) presenting to eight emergency departments (EDs) were evaluated from the Internet Tracking Registry of Acute Coronary Syndromes. Groups were selected from final ED diagnosis: 1) acute myocardial infarction (AMI), n = 400; 2) unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI), n = 1,153; and 3) nonacute coronary syndrome chest pain (non-ACS CP), n = 6,382. American College of Cardiology/American Heart Association guidelines for AMI and UA/NSTEMI were used to evaluate racial disparities with logistic regression models. Odds ratios (ORs) were adjusted for age, gender, guideline publication, and insurance status. Non-ACS CP patients were assessed by comparing electrocardiographic (ECG)/laboratory evaluation, medical treatment, admission rates, and invasive and noninvasive testing for coronary artery disease (CAD).

RESULTS

African Americans with UA/NSTEMI received glycoprotein IIb/IIIa receptor inhibitors less often than whites (OR, 0.41; 95% CI = 0.19 to 0.91). African Americans with non-ACS CP underwent ECG/laboratory evaluation, medical treatment, and invasive and noninvasive testing for CAD less often than whites (p < 0.05). Other nonwhites with non-ACS CP were admitted and received invasive testing for CAD less often than whites (p < 0.01). African Americans and other nonwhites with AMI underwent catheterization less frequently than whites (OR, 0.45; 95% CI = 0.29 to 0.71 and OR, 0.40; 95% CI = 0.17 to 0.92, respectively). A similar disparity in catheterization was noted in UA/NSTEMI therapy (OR, 0.53; 95% CI = 0.40 to 0.68 and OR, 0.68; 95% CI = 0.47 to 0.99).

CONCLUSIONS

Racial disparities in acute chest pain management extend beyond cardiac catheterization. Poor compliance with recommended treatments for ACS may be an explanation.

Prospective evaluation of emergency department patients with potential coronary syndromes using initial absolute CK-MB vs. CK-MB relative index

We compared the predictive properties of an initial absolute creatine kinase-MB (CK-MB) to creatine kinase-MB relative index (CK-MB RI) for detecting acute myocardial infarction (AMI), acute coronary syndromes (ACS), and serious cardiac events (SCE). Consecutive patients > 24 years of age with chest pain who received an electrocardiogram (EKG) as part of their Emergency Department (ED) evaluation had CK and CK-MB drawn at presentation. Patients were followed prospectively during their hospital course. The main outcome was AMI, ACS or SCE (death, AMI, dysrhythmias, CHF, PTCA/stent, CABG) within 30 days. The sensitivity, specificity, PPV and NPV of CK-MB and CK-MB RI to predict AMI, ACS, and SCE were calculated with 95% CIs. We enrolled 2028 patients. There were 105 patients (5.2%) with AMI, 266 (13.1%) with ACS, and 150 with SCE (7.4%). Absolute CK-MB had a higher sensitivity than CK-MB RI for AMI (52.0 vs. 46.9, respectively), ACS (23.5 vs. 20.8, respectively), and SCE (39.6 vs. 36.0, respectively), but a lower specificity than CK-MB RI for AMI (93.2 vs. 96.1, respectively), ACS (93.1 vs. 96.1, respectively) and SCE (93.3 vs. 96.3, respectively); and lower PPV for AMI (35.7 vs. 46.5, respectively), ACS (42.0 vs. 53.4, respectively) and SCE (38.5 vs. 50.5, respectively). The negative predictive values were similar for all outcomes. We conclude that the risk stratification of ED chest pain patients by absolute CK-MB has higher sensitivity, similar NPV, but a lower specificity and PPV than CK-MB relative index for detection of AMI, ACS, and SCE. The optimal test depends upon the relative importance of the sensitivity or specificity for clinical decision-making in an individual patient.

Combination of Goldman risk and initial cardiac troponin I for emergency department chest pain patient risk stratification

BACKGROUND

Accurate identification of low-risk emergency department (ED) chest pain patients who may be safe for discharge has not been well defined. Goldman criteria have reliably risk-stratified patients but have not identified any subset safe for ED release. Cardiac troponin I (cTnI) values have also been shown to risk-stratify patients but have not identified a subset safe for ED release.

OBJECTIVE

To test the hypothesis that ED chest pain patients with a Goldman risk of < or =4% and a single negative cTnI (< or =0.3 ng/mL) at the time of ED presentation would be safe for discharge [<1% risk for death, acute myocardial infarction (AMI), revascularization].

METHODS

A prospective cohort study was performed in which consecutive ED chest pain patients were enrolled from July 1999 to November 2000. Data collected included patient demographics, medical and cardiac history, electrocardiogram, and creatine kinase-MB and cTnI. Goldman risk stratification score was calculated while patients were still in the ED. Hospital course was followed daily. Telephone follow-up occurred at 30 days. The main outcome was death, AMI, or revascularization (percutaneous transluminal coronary angioplasty/stents/coronary artery bypass grafting) within 30 days.

RESULTS

Of 2,322 patients evaluated, 998 had both a Goldman risk < or =4% and a cTnI < or =0.3 ng/mL. During the initial hospitalization, 37 patients met the composite endpoint (3.7%): 6 deaths (0.7%), 17 AMIs (1.7%), 18 revascularizations (1.8%). Between the time of hospital discharge and 30-day follow-up, 15 patients met the composite endpoint: 4 deaths (0.4%), 6 AMIs (0.6%), and 5 revascularizations (0.5%). Overall, 49 patients met the composite endpoint (4.9%; 95% CI = 3.6% to 6.2%): 10 deaths (1.0%; 95% CI = 0.4% to 1.6%); 23 AMIs (2.3%; 95% CI = 1.4% to 3.2%), and 23 revascularizations (2.3%; 95% CI = 1.4% to 3.2%) within 30 days of presentation.

CONCLUSIONS

The combination of two risk stratification modalities for ED chest pain patients (Goldman risk < or =4% and cTnI < or =0.3 ng/mL) did not identify a subgroup of chest pain patients at <1% risk for death, AMI, or revascularization within 30 days.

A new system for sternal intraosseous infusion in adults

BACKGROUND

Intraosseous (IO) infusion provides an alternative route for the administration of fluids and medications when difficulty with peripheral or central lines is encountered during resuscitation of critically ill and injured patients.

OBJECTIVE

To report the first 50 uses of a new system for emergency IO infusion into the sternum in adults, the Pyng F.A.S.T.1 IO infusion system.

METHODS

Six emergency departments and five prehospital emergency medical services (EMS) sites in Canada and the United States provided clinical and/or research data on their use of the IO system in a pilot study of success rates, insertion times, and complications. Indications for use included adult patient, urgent need for fluids or medications, and unacceptable delay or inability to achieve standard vascular access. A basic data set was standardized for all sites, and some sites collected additional data.

RESULTS

The overall success rate for achieving vascular access with the system was 84%. Success rates were 74% for first-time users, and 95% for experienced users. Failure to achieve vascular access occurred most frequently in patients (5 of 9) described subjectively by the user as "very obese," in whom there was a thick layer of tissue overlying the sternum. Mean time to achieve vascular access was 77 seconds. Flow rates of up to 80 mL/min were reported for gravity drip, and more than 150 mL/min by syringe bolus. Pressure cuffs were also used successfully, although fluid rate was controlled by clamping the line. Further research on flow rates is needed. No complications or complaints were reported at two-month follow-up.

CONCLUSION

These early data indicate that sternal IO infusion using the new F.A.S.T.1 IO system may provide rapid, safe vascular access and may be a useful technique for reducing unacceptable delays in the provision of emergency treatment.