COVID-19: Seroprevalence and Vaccine Responses in UK Dental Care Professionals.

Dental care professionals (DCPs) are thought to be at enhanced risk of occupational exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, robust data to support this from large-scale seroepidemiological studies are lacking. We report a longitudinal seroprevalence analysis of antibodies to SARS-CoV-2 spike glycoprotein, with baseline sampling prior to large-scale practice reopening in July 2020 and follow-up postimplementation of new public health guidance on infection prevention control (IPC) and enhanced personal protective equipment (PPE). In total, 1,507 West Midlands DCPs were recruited into this study in June 2020. Baseline seroprevalence was determined using a combined IgGAM enzyme-linked immunosorbent assay and the cohort followed longitudinally for 6 mo until January/February 2021 through the second wave of the coronavirus disease 2019 pandemic in the United Kingdom and vaccination commencement. Baseline seroprevalence was 16.3%, compared to estimates in the regional population of 6% to 7%. Seropositivity was retained in over 70% of participants at 3- and 6-mo follow-up and conferred a 75% reduced risk of infection. Nonwhite ethnicity and living in areas of greater deprivation were associated with increased baseline seroprevalence. During follow-up, no polymerase chain reaction-proven infections occurred in individuals with a baseline anti-SARS-CoV-2 IgG level greater than 147.6 IU/ml with respect to the World Health Organization international standard 20-136. After vaccination, antibody responses were more rapid and of higher magnitude in those individuals who were seropositive at baseline. Natural infection with SARS-CoV-2 prior to enhanced PPE was significantly higher in DCPs than the regional population. Natural infection leads to a serological response that remains detectable in over 70% of individuals 6 mo after initial sampling and 9 mo from the peak of the first wave of the pandemic. This response is associated with protection from future infection. Even if serological responses wane, a single dose of the Pfizer-BioNTech 162b vaccine is associated with an antibody response indicative of immunological memory.

Validation of a combined ELISA to detect IgG, IgA and IgM antibody responses to SARS-CoV-2 in mild or moderate non-hospitalised patients.

BACKGROUND: Frequently SARS-CoV-2 results in mild or moderate disease with potentially lower concentrations of antibodies compared to those that are hospitalised. Here, we validated an ELISA using SARS-CoV-2 trimeric spike glycoprotein, with targeted detection of IgG, IgA and IgM (IgGAM) using serum and dried blood spots (DBS) from adults with mild or moderate disease. METHODS: Targeting the SARS-CoV-2 trimeric spike, a combined anti-IgG, IgA and IgM serology ELISA assay was developed using 62 PCR-confirmed non-hospitalised, mild or moderate COVID-19 samples, ≥14 days post symptom onset and 624 COVID-19 negative samples. The assay was validated using 73 PCR-confirmed non-hospitalised, mild or moderate COVID-19 samples, ≥14 days post symptom onset and 359 COVID-19 negative serum samples with an additional 81 DBSs. The assay was further validated in 226 PCR-confirmed non-hospitalised, mild or moderate COVID-19 samples, ≥14 days post symptom onset and 426 COVID-19 negative clinical samples. RESULTS: A sensitivity and specificity of 98.6% (95% CI, 92.6-100.0), 98.3% (95% CI, 96.4-99.4), respectively, was observed following validation of the SARS-CoV-2 ELISA. No cross-reactivities with endemic coronaviruses or other human viruses were observed, and no change in results were recorded for interfering substances. The assay was stable at temperature extremes and components were stable for 15 days once opened. A matrix comparison showed DBS to correlate with serum results. Clinical validation of the assay reported a sensitivity of 94.7% (95% CI, 90.9-97.2%) and a specificity of 98.4% (95% CI, 96.6-99.3%). CONCLUSIONS: The human anti-IgGAM SARS-CoV-2 ELISA provides accurate and sensitive detection of SARS-CoV-2 antibodies in non-hospitalised adults with mild or moderate disease. The use of dried blood spots makes the assay accessible to the wider community.

Management of allergy to penicillins and other beta-lactams.

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

A UK national survey of investigations for beta-lactam hypersensitivity - heterogeneity in practice and a need for national guidelines - on behalf of British Society for Allergy and Clinical Immunology (BSACI).

BACKGROUND: Beta lactams (BL) are the most widely prescribed antibiotics in the UK and the commonest cause of hypersensitivity reactions. There are no UK guidelines for BL testing and the most relevant guidelines were devised by the European Network for Drug Allergy (ENDA) on behalf of the European Academy of Allergy and Clinical Immunology. OBJECTIVE: Delivery of allergy services differs across Europe, so this survey was designed to investigate how closely UK practice adhered to these guidelines. METHODS: An online survey, using surveymonkey.com software, was sent to all consultants offering an allergy service in the UK and who were members of either BSACI or 'Travellers' (Immunology consultant group). RESULTS: The response rate was 48% (n=81/165) and BL allergy testing was undertaken by 78% of respondents. All responders requested SsIgE, although four responders stated they rarely requested. Skin testing was undertaken by 87% of respondents who perform beta lactam testing with 17% undertaking skin prick testing (SPT) only, 77% SPT followed by intra-dermal testing (IDT) if the former were negative or indeterminate and 6% SPT and IDT in all cases. The drugs, doses and protocols for skin testing varied considerably. Drug provocation testing was undertaken by 87% of respondents who undertake beta lactam testing with significant heterogeneity in protocols. Respondents that investigated ≤ 20 patients per year demonstrated lower adherence to ENDA recommendations compared to those who saw > 20. Following positive testing, 79% advised avoidance of all penicillins only and the remainder advised additional drug avoidance. CONCLUSION AND CLINICAL RELEVANCE: This survey revealed variation in the investigation and management of BL hypersensitivity in the UK with some centres reporting procedures that could potentially put patients at risk of anaphylaxis if allergy was falsely excluded. This survey highlights an urgent need for evidence based national guidelines and standardisation of practice.

Neutrophil chemotaxis in granulomatosis with polyangiitis (Wegener's) and idiopathic pulmonary fibrosis.

The presence of antineutrophil cytoplasmic antibodies in granulomatosis with polyangiitis (Wegener's) (GPA) implicates the neutrophil as a key effector cell. Previous studies have reported elevated neutrophil counts in the lung, although the determinants of neutrophil chemotaxis in the GPA lung are unknown. Bronchoalveolar lavage fluid (BALF) cell counts, myeloperoxidase (MPO) and chemokines were measured in 27 patients with GPA, 20 disease controls with idiopathic pulmonary fibrosis (IPF) and six healthy controls. CXC chemokine ligand (CXCL)8, interleukin (IL)-1ß, epithelial neutrophil-activating protein 78, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor were measured by ELISA. The neutrophil chemotactic potential of BALF was investigated using the under-agarose method, and specific antibodies were used to examine the role of CXCL8 and IL-1ß. GPA BALF had an increased neutrophil percentage, and elevated MPO, CXCL8 and G-CSF concentrations compared with healthy controls. Chemotaxis of control neutrophils towards BALF from patients with active (p=0.006) and remission (p=0.077) GPA, and IPF (p=0.001) patients was increased compared with normal controls. BALF-induced chemotaxis correlated with BALF IL-1ß (r=0.761, p=0.001) and CXCL8 (r=0.640, p=0.012) in GPA, and was inhibited by anti-CXCL8 (85%; p<0.001) and anti-IL-1ß (69%; p<0.001). Our study confirms a neutrophilia and pro-inflammatory alveolar milieu that persists in clinical remission. CXCL8 and IL-1ß appear to play important roles in the neutrophil chemotactic response to BALF.

Retrospective case series analysis of penicillin allergy testing in a UK specialist regional allergy clinic.

INTRODUCTION: Penicillin allergy is the most common drug allergy. Skin testing for the major (PPL) and minor determinants (MDMs) of penicillin offers increased sensitivity and specificity over in vitro testing alone. Following a worldwide absence of reagents, a new kit was licensed in the UK in 2008 (Diater, Spain) and this report evaluates its use in a UK specialist allergy clinic. METHODS: Prospective data on 50 consecutive patients tested with the new reagents were collected. The departmental protocol is adapted from the 2003 EAACI position paper. RESULTS: 14% (7/50) and 12% (6/50) of patients were diagnosed with immediate and non-immediate reactions respectively. The negative predictive value of the PPL and MDM reagents at the neat concentration for an immediate reaction was 93% (true negatives 37, false negatives 3). Two patients experienced systemic reactions to DPT in the absence of demonstrable specific IgE. None of the patients were diagnosed using skin prick testing alone or at lower concentrations of IDT. Five patients were diagnosed at the IDT stage and two at the DPT stage in the absence of demonstrable specific IgE. Six patients were diagnosed with non-immediate reactions, two on IDT alone and four following IDT and DPT. CONCLUSION: The new PPL and MDM determinants offer enhanced sensitivity when evaluating ß-lactam hypersensitivity; however, there are limitations to the current testing regimens. The UK would benefit from local guidelines, which incorporate the new reagents and acknowledge the high amoxicillin prescription rate and the relatively lower specialist-to-patient ratio in this country.

Pulmonary infection in Wegener granulomatosis and idiopathic pulmonary fibrosis.

RATIONALE: Wegener granulomatosis (WG) has previously been associated with increased nasal carriage of Staphylococcus aureus, but no studies have investigated the occurrence of pathogen growth in the lower airways. OBJECTIVES: To culture bronchoalveolar lavage fluid (BALF) from patients with WG, patients with idiopathic pulmonary fibrosis (IPF) and normal controls. METHODS: 33 patients with WG, 22 with IPF and 8 normal controls underwent bronchoscopy and bronchoalveolar lavage. Quantitative culture established bacterial levels in the lower airways. Culture experiments were designed to investigate whether BALF is a supportive environment for S aureus growth. BALF cytokines were measured by ELISA. RESULTS: Pathogens were commonly grown from BALF of patients with WG and those with IPF. S aureus was particularly associated with patients with WG both in relapse and in remission. BALF levels of interleukin 1 receptor antagonist (IL1ra) were statistically significantly elevated in those patients who grew a pathogen from lavage fluid. BALF from patients with WG and IPF stimulated S aureus growth compared with normal lavage fluid. CONCLUSIONS: Pathogens are more commonly isolated from BALF from patients with WG than from that of patients with IPF or normal controls, and with a different culture profile. IL1ra was associated with pathogen growth in WG and IPF. WG BALF is a trophic environment for S aureus growth. Pulmonologists treating patients with acute or relapsing WG should consider bronchoscopic microbiological sampling and consider antibiotics with antistaphylococcal activity.

MMP expression and abnormal lung permeability are important determinants of outcome in IPF.

Matrix metalloproteinases (MMPs) degrade all of the extracellular matrix components of the intersititium and may play a role in abnormal alveolar permeability, which is a feature of idiopathic pulmonary fibrosis (IPF). The aims of the present study were to evaluate MMP protein levels in patients with IPF and determine any relationship to treatment and markers of permeability. In total, 20 patients with IPF and eight normal controls underwent bronchoalveolar lavage. MMP, tissue inhibitor of metalloproteinase, and vascular endothelial growth factor (VEGF) levels were related to clinical outcome and protein permeability index. MMP-3, -7, -8 and -9 were elevated in IPF lavage fluid and levels remained high despite treatment. Levels of MMP-3, -7, -8 and -9, VEGF and protein permeability index were higher in those who died early during follow-up. VEGF, and MMP-8 and -9 levels were higher in those with a rapidly declining lung function over 1 yr. Levels of MMP-3, -7, -8 and -9 correlated with an increased permeability index. Matrix metalloproteinase levels were elevated in idiopathic pulmonary fibrosis patients and were not modulated by current standard treatment. Matrix metalloproteinase production through an interaction with the known vascular permogen, vascular endothelial growth factor, was potentially associated with abnormal capillary permeability and may have potentiated the neo-angiogenesis seen in idiopathic pulmonary fibrosis. The changes were greatest in those who died or progressed during follow-up, suggesting that drugs targeting vascular endothelial growth factor or matrix metalloproteinase activity warrant assessment as novel therapy for idiopathic pulmonary fibrosis.

Soluble endostatin is a novel inhibitor of epithelial repair in idiopathic pulmonary fibrosis.

BACKGROUND AND AIM: Aberrant angiogenesis and defective epithelial repair are key features of idiopathic pulmonary fibrosis (IPF). Endostatin is an antiangiogenic peptide with known effects on endothelial cells. This study aimed to establish the levels of endostatin in the bronchoalveolar lavage fluid (BALF) in IPF and to investigate its actions on distal lung epithelial cells (DLEC) and primary type II cells. METHODS: 20 patients with IPF and 10 controls underwent BAL. Endostatin was measured by ELISA. BALF cytokines and matrix metalloproteinase (MMP)-3 were measured by Luminex array. Primary DLEC monolayers were wounded and treated with endostatin. Apoptosis and cell viability were assessed. RESULTS: Endostatin was elevated in the BALF and plasma of patients with IPF compared with normal controls. There was a negative correlation between endostatin, forced vital capacity and gas transfer. Endostatin correlated with a number of proinflammatory cytokines and MMP3. Physiological endostatin doses inhibited DLEC wound repair by 44% in an effect that was partially FasL and caspase dependent. Endostatin increased apoptosis rates by 8% and reduced their viability by 34%. Similar effects of endostatin were seen in primary type II cells in terms of inhibition of wound repair and proliferation. CONCLUSIONS: Elevated BALF endostatin levels correlated with a number of elevated cytokines, MMP3 and lung function in IPF. Endostatin is a novel inhibitor of DLEC wound repair, inducing apoptosis and reducing cell viability in a FasL and caspase dependent manner. Endostatin may play a role in aberrant epithelial repair in IPF.

Structure of interfacial liquids: X-ray scattering studies.

We have used synchrotron x rays to study three different liquids near solid-liquid interfaces. For either ultrathin (45-90 A) or thick ( approximately 5000 A) liquid films on silicon substrates, we find (on the basis of diffraction peaks or specular reflectivity data) that the molecules form 3-6 layers at the interface, with plane spacings close to the molecular dimensions. Rough surfaces and/or impurities reduce the density oscillation amplitudes. Making the liquid film very thin does not observably enhance the effect, which implies that layering is present even at an isolated interface (i.e., in a semi-infinite liquid). On the other hand, predeposited impurities diffuse away from the interface more easily if the liquid films are thick. The liquids studied are nonconducting, nonpolar, and nonreactive; the molecules are roughly spherical; and our substrate surface has no lateral structure. Thus our observations should apply to any liquid near a hard wall.

A rabbit model of toxic shock syndrome that uses a constant, subcutaneous infusion of toxic shock syndrome toxin 1.

We have developed a rabbit model of toxic shock syndrome that uses a subcutaneous infusion pump to administer toxic shock syndrome toxin 1 (TSST-1). A dose of 150 micrograms, infused at a constant rate over a period of 7 days, resulted in a characteristic illness highlighted by fever, conjunctival hyperemia, cachexia, and lethargy. The illness was uniformly fatal, with a mean interval until death of 3.2 +/- 0.4 days. Serial determinations of serum chemistries confirmed the multisystem nature of this illness. Rabbits developed profound hypocalcemia, with levels falling from 15.5 +/- 0.2 to 7.6 +/- 0.4 mg/dl under the influence of TSST-1. Blood urea nitrogen and creatinine rose dramatically, in the setting of oliguria or anuria. Serum glutamicpyruvic transaminase was the most reliable indicator of hepatic dysfunction, with the mean rising from 48 U/liter before administration of TSST-1 to 546 U/liter among rabbits surviving 2 days of the infusion. Creatine phosphokinase also rose dramatically in 10 of 16 rabbits. Rabbits demonstrated relative neutrophilia and lymphopenia as well as an increase in the partial thromboplastin time. Histopathologic examination demonstrated disease of multiple organs, particularly the liver, spleen, and lymph nodes, all of which demonstrated inflammation, thrombosis, hemorrhage, and erythrophagocytosis. The concurrent administration of prednisolone with TSST-1 prevented death in four of four rabbits and greatly lessened the morbidity. Rabbits were not protected from morbidity or mortality by the concurrent administration of polymyxin B. We believe that a constant, subcutaneous infusion of TSST-1 in rabbits provides a reproducible model for studying the pathogenesis of TSS.

Pregnancy toxemia (eclampsia) in Syrian golden hamsters.

Late-term pregnant Syrian golden hamsters (Mesocricetus auratus) died within 24 hours of arrival in our facility. Disseminated thrombi were found in many organs, particularly in the kidneys, liver, intestines, and placenta. Pathogenic bacteria were not identified in bacterial cultures of the liver.