The Majority of SARS-CoV-2 Plasma Cells are Excluded from the Bone Marrow Long-Lived Compartment 33 Months after mRNA Vaccination.

The goal of any vaccine is to induce long-lived plasma cells (LLPC) to provide life-long protection. Natural infection by influenza, measles, or mumps viruses generates bone marrow (BM) LLPC similar to tetanus vaccination which affords safeguards for decades. Although the SARS-CoV-2 mRNA vaccines protect from severe disease, the serologic half-life is short-lived even though SARS-CoV-2-specific plasma cells can be found in the BM. To better understand this paradox, we enrolled 19 healthy adults at 1.5-33 months after SARS-CoV-2 mRNA vaccine and measured influenza-, tetanus-, or SARS-CoV-2-specific antibody secreting cells (ASC) in LLPC (CD19-) and non-LLPC (CD19+) subsets within the BM. All individuals had IgG ASC specific for influenza, tetanus, and SARS-CoV-2 in at least one BM ASC compartment. However, only influenza- and tetanus-specific ASC were readily detected in the LLPC whereas SARS-CoV-2 specificities were mostly excluded. The ratios of non-LLPC:LLPC for influenza, tetanus, and SARS-CoV-2 were 0.61, 0.44, and 29.07, respectively. Even in five patients with known PCR-proven history of infection and vaccination, SARS-CoV-2-specific ASC were mostly excluded from the LLPC. These specificities were further validated by using multiplex bead binding assays of secreted antibodies in the supernatants of cultured ASC. Similarly, the IgG ratios of non-LLPC:LLPC for influenza, tetanus, and SARS-CoV-2 were 0.66, 0.44, and 23.26, respectively. In all, our studies demonstrate that rapid waning of serum antibodies is accounted for by the inability of mRNA vaccines to induce BM LLPC.

Hepatic Encephalopathy-A Guide to Laboratory Testing.

Hepatic encephalopathy (HE) remains both a clinical diagnosis and one of exclusion. Laboratory testing is largely focused on identifying precipitating factors. Ammonia levels in the blood can be helpful for the diagnosis of HE but are not required for confirmation. More recent literature is lending support to the prognostic capabilities of ammonia in cirrhosis, both in predicting future HE events and in determining outcomes in hospitalized patients. Accurate ammonia testing requires strict protocols to avoid common pitfalls in the measurement of this labile analyte. Future studies investigating the utility of other laboratory testing to diagnose, stage, or predict HE are encouraged.

Single center outcomes from parenchymal-sparing resections and microwave ablations for neuroendocrine tumor liver metastases.

BACKGROUND: Reported outcomes after surgical debulking in patients with advanced neuroendocrine tumor liver metastases (NETLM) are sparse. METHODS: NETLM patients that underwent surgical debulking from 2019 to 2021 were reviewed. Trends in perioperative liver function, complications, symptom response, and progression-free survival were examined. RESULTS: 1069 liver lesions were debulked from 53 patients using a combination of parenchymal-sparing resections (PSR) and ultrasound-guided microwave ablations (MWA). Post-operative transaminitis and thrombocytopenia were common, and severity correlated with increasing number of lesions. Laboratory markers for synthetic liver function did not differ according to the number of lesions debulked. 13% of patients sustained a Clavien-Dindo grade 3 or 4 complication which was not associated with the number of lesions targeted. All patients with preoperative symptoms had improvement after surgery. Median time to progression was 10.9 months. CONCLUSIONS: PSR with MWA for large numbers of NETLM is safe and effective for symptom control and does not affect synthetic liver function.

Association between travel distance and overall survival among patients with adrenocortical carcinoma.

BACKGROUND AND OBJECTIVES: Regionalization of care is associated with improved perioperative outcomes after adrenalectomy. However, the relationship between travel distance and treatment of adrenocortical carcinoma (ACC) is unknown. We investigated the association between travel distance, treatment, and overall survival (OS) among patients with ACC. METHODS: Patients diagnosed with ACC between 2004 and 2017 were identified with the National Cancer Database. Long distance was defined as the highest quintile of travel (≥42.2 miles). The likelihood of surgical management and adjuvant chemotherapy (AC) were determined. The association between travel distance, treatment, and OS was evaluated. RESULTS: Of 3492 patients with ACC included, 2337 (66.9%) received surgery. Rural residents were more likely to travel long distances for surgery than metropolitan residents (65.8% vs. 15.5%, p < 0.001), and surgery was associated with improved OS (HR 0.43, 95% CI 0.34-0.54). Overall, 807 (23.1%) patients received AC with rates decreasing approximately 1% per 4-mile travel distance increase. Also, long distance travel was associated with worse OS among surgically treated patients (HR 1.21, 95% CI 1.05-1.40). CONCLUSIONS: Surgery was associated with improved overall survival for patients with ACC. However, increased travel distance was associated with lower likelihood to receive adjuvant chemotherapy and decreased overall survival.

mRNA bivalent booster enhances neutralization against BA.2.75.2 and BQ.1.1.

The emergence of the highly divergent SARS-CoV-2 Omicron variant has jeopardized the efficacy of vaccines based on the ancestral spike. The bivalent COVID-19 mRNA booster vaccine within the United States is comprised of the ancestral and the Omicron BA.5 spike. Since its approval and distribution, additional Omicron subvariants have been identified with key mutations within the spike protein receptor binding domain that are predicted to escape vaccine sera. Of particular concern is the R346T mutation which has arisen in multiple subvariants, including BA.2.75.2 and BQ.1.1. Using a live virus neutralization assay, we evaluated serum samples from individuals who had received either one or two monovalent boosters or the bivalent booster to determine neutralizing activity against wild-type (WA1/2020) virus and Omicron subvariants BA.1, BA.5, BA.2.75.2, and BQ.1.1. In the one monovalent booster cohort, relative to WA1/2020, we observed a reduction in neutralization titers of 9-15-fold against BA.1 and BA.5 and 28-39-fold against BA.2.75.2 and BQ.1.1. In the BA.5-containing bivalent booster cohort, the neutralizing activity improved against all the Omicron subvariants. Relative to WA1/2020, we observed a reduction in neutralization titers of 3.7- and 4-fold against BA.1 and BA.5, respectively, and 11.5- and 21-fold against BA.2.75.2 and BQ.1.1, respectively. These data suggest that the bivalent mRNA booster vaccine broadens humoral immunity against the Omicron subvariants.

Diagnosis and management of chronic hepatitis B: A patient-friendly summary of the 2018 American Association for the Study of Liver Diseases practice guidance.

Content available: Author Interview and Audio Recording.

Telesimulation to Improve Critical Decision-Making in Prehospital Airway Management: A Feasibility Study.

OBJECTIVES: Telesimulation, in which learners and evaluators use technology to connect remotely to simulation-based learning activities, is effective for skills and decision-making review. Historical models in which learners are colocated with the simulation equipment have inherent issues, especially for emergency medical services (EMS) providers. This feasibility study placed the evaluators in the simulation center, whereas the learners were at a distance steering the scenario evolution through telehealth technologies. METHODS: Volunteer EMS providers across South Carolina with varying levels of training and experience completed difficult airway management scenarios focused on clinical decision making. The program consisted of pre- and postexperience examinations, a lecture, and increasingly complicated simulations using high-fidelity mannequins that were facilitated by local trainers under the direction of remote trainees. Audio and video content, including vital signs and cardiac monitoring, were live streamed. Participants worked in two-person teams with lead providers on each scenario clinically assessing and managing cases of anaphylaxis. Data were collected from the simulations using Laerdal software, as well as examination and survey results. RESULTS: A total of 24 participants completed all of the elements of the training. Trends toward improvement in times to bag-mask ventilation and initial epinephrine administration were noted. Average cognitive test scores increased by 9.6%, and learners reported improved comfort with simulation (75%, P ≥ 0.0001) and videoconferencing (83%, P ≥ 0.0001). They also reported high degrees of comfort with intubation (73.3%) following the training. CONCLUSIONS: This method of telesimulation appears to be a viable addition to continuing EMS education and may address access issues for some providers.

COVID-19 and plasma cells: Is there long-lived protection?

Infection with SARS-CoV-2, the etiology of the ongoing COVID-19 pandemic, has resulted in over 450 million cases with more than 6 million deaths worldwide, causing global disruptions since early 2020. Memory B cells and durable antibody protection from long-lived plasma cells (LLPC) are the mainstay of most effective vaccines. However, ending the pandemic has been hampered by the lack of long-lived immunity after infection or vaccination. Although immunizations offer protection from severe disease and hospitalization, breakthrough infections still occur, most likely due to new mutant viruses and the overall decline of neutralizing antibodies after 6 months. Here, we review the current knowledge of B cells, from extrafollicular to memory populations, with a focus on distinct plasma cell subsets, such as early-minted blood antibody-secreting cells and the bone marrow LLPC, and how these humoral compartments contribute to protection after SARS-CoV-2 infection and immunization.

Adolescent exposure to a solid high-fat, high-sugar 'cafeteria' diet leads to more pronounced changes in metabolic measures and gut microbiome composition than liquid sugar in female rats.

Adolescence is a dynamic developmental period where unhealthy solid foods and sugar-sweetened beverages are routinely consumed. Regular consumption of solid 'junk' foods rich in fat and refined carbohydrate and sugar-sweetened beverages are independently associated with an increased risk of metabolic disease and altered gut microbiome composition. Here we used a validated rat model to determine the effects of a solid 'cafeteria' diet high in fat and sugar (Caf) and 10% liquid sucrose solution (Suc) on food intake, metabolic measures and gut microbiome composition. Sixty adolescent female Sprague-Dawley rats were fed standard chow with or without continuous access to Caf diet and/or Suc for 13 weeks (n = 15). Exposure to cafeteria diet and liquid sucrose each increased body weight gain and adiposity, with no synergistic effects. Gut microbiome alpha and beta diversity parameters were more strongly affected by exposure to Caf diet than access to liquid Suc. Nonetheless, providing liquid sucrose to rats fed chow altered gut microbiome beta diversity and significantly enriched the abundance of five taxa from order Clostridiales. By contrast, in the two groups fed Caf, Suc did not alter beta diversity, with few differentially abundant taxa between Caf and Caf + Suc groups. In sum, liquid sucrose and solid cafeteria diet exerted largely independent effects on metabolic and gut microbiome measures. Interventions targeting either solid junk foods or sugary beverages are likely to reduce diet-related disease burden.

Bispecific antibodies targeting distinct regions of the spike protein potently neutralize SARS-CoV-2 variants of concern.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern threatens the efficacy of existing vaccines and therapeutic antibodies and underscores the need for additional antibody-based tools that potently neutralize variants by targeting multiple sites of the spike protein. We isolated 216 monoclonal antibodies targeting SARS-CoV-2 from plasmablasts and memory B cells collected from patients with coronavirus disease 2019. The three most potent antibodies targeted distinct regions of the receptor binding domain (RBD), and all three neutralized the SARS-CoV-2 Alpha and Beta variants. The crystal structure of the most potent antibody, CV503, revealed that it binds to the ridge region of SARS-CoV-2 RBD, competes with the angiotensin-converting enzyme 2 receptor, and has limited contact with key variant residues K417, E484, and N501. We designed bispecific antibodies by combining nonoverlapping specificities and identified five bispecific antibodies that inhibit SARS-CoV-2 infection at concentrations of less than 1 ng/ml. Through a distinct mode of action, three bispecific antibodies cross-linked adjacent spike proteins using dual N-terminal domain­RBD specificities. One bispecific antibody was greater than 100-fold more potent than a cocktail of its parent monoclonals in vitro and prevented clinical disease in a hamster model at a dose of 2.5 mg/kg. Two bispecific antibodies in our panel comparably neutralized the Alpha, Beta, Gamma, and Delta variants and wild-type virus. Furthermore, a bispecific antibody that neutralized the Beta variant protected hamsters against SARS-CoV-2 expressing the E484K mutation. Thus, bispecific antibodies represent a promising next-generation countermeasure against SARS-CoV-2 variants of concern.

MicroRNA-155 Modulates Macrophages' Response to Non-Tuberculous Mycobacteria through COX-2/PGE2 Signaling.

Non-tuberculous mycobacteria (NTM) have been recognized as a causative agent of various human diseases, including severe infections in immunocompromised patients, such as people living with HIV. The most common species identified is the Mycobacterium avium-intracellulare complex (MAI/MAC), accounting for a majority of infections. Despite abundant information detailing the clinical significance of NTM, little is known about host-pathogen interactions in NTM infection. MicroRNAs (miRs) serve as important post-transcriptional regulators of gene expression. Using a microarray profile, we found that the expression of miR-155 and cyclo-oxygenase 2 (COX-2) is significantly increased in bone-marrow-derived macrophages from mice and human monocyte-derived macrophages from healthy volunteers that are infected with NTM. Antagomir against miR-155 effectively suppressed expression of COX-2 and reduced Prostaglandin E2(PGE2) secretion, suggesting that COX-2/PGE2 expression is dependent on miR-155. Mechanistically, we found that inhibition of NF-κB activity significantly reduced miR-155/COX-2 expression in infected macrophages. Most importantly, blockade of COX-2, E-prostanoid receptors (EP2 and EP4) enhanced killing of MAI in macrophages. These findings provide novel mechanistic insights into the role of miR-155/COX-2/PGE2 signalling and suggest that induction of these pathways enhances survival of mycobacteria in macrophages. Defining host-pathogen interactions can lead to novel immunomodulatory therapies for NTM infections which are difficult to treat.

Heterofunctional Particles as Single Cell Sensors to Capture Secreted Immunoglobulins and Isolate Antigen-Specific Antibody Secreting Cells.

Isolating cells based on their secreted proteins remain a challenge. The authors demonstrate a capacity for high throughput single-cell protein secretion analysis and isolation based on heterofunctional particles combined with fluorescence activated cell sorting (FACS). The workflow shows that antibody secreting cells (ASCs) specific for the H1 protein from influenza virus can be isolated from B cells. The workflow consists of incubating anti-CD27 particles with the ASCs, capturing locally secreted immunoglobulins with Protein G on the particles, and identifying immunoglobulins specific to H1 via fluorescent labeled antigens followed by FACS to enrich antigen-specific ASCs. Two particles designs, Janus and mixed, are tested with hybridoma cells. Mixed particles are found to improve antibody collection, while Janus particles are found to bind target cells more effectively. Targeted hybridoma cells in coculture with non-specific hybridoma cells are identified with a sensitivity of 96% and specificity of 98%. Heterofunctional particles are used to capture ASCs that secrete antibodies specific for influenza virus from B cells from healthy adults isolated from blood after vaccination. Positive H1-tetramer sorted ASCs are validated using single ASC cultures and identify 23/56 cells specific for H1 demonstrating 164-fold enrichment from total B cells and 14.6-fold enrichment from total ASCs.

Immediate Reactions After the First Dose of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Messenger RNA Vaccines Do Not Preclude Second-Dose Administration.

Addressing coronavirus disease 2019 (COVID-19) vaccine hesitancy and minimizing potential vaccine contraindications are critical to combatting the pandemic. We describe a practical approach to immediate adverse events after the first dose of messenger RNA vaccines for severe acute respiratory syndrome coronavirus 2, focusing on diagnosis and management of allergic reactions.