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.83 ht 1 Abbreviations: IgG, immunoglobulin G; IgRT, immunoglobulin replacement therapy; IQR, interquartile range. We demonstrate that, in previously stable patients, IgRT dose reductions lead to a reduction in trough IgG, which is associated with an increased frequency of infections requiring outpatient antibiotic use. [Extracted from the article]

Summary: Coronavirus 19 (COVID‐19) has been associated with both transient and persistent systemic symptoms that do not appear to be a direct consequence of viral infection. The generation of autoantibodies has been proposed as a mechanism to explain these symptoms. To understand the prevalence of autoantibodies associated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, we investigated the frequency and specificity of clinically relevant autoantibodies in 84 individuals previously infected with SARS‐CoV‐2, suffering from COVID‐19 of varying severity in both the acute and convalescent setting. These were compared with results from 32 individuals who were on the intensive therapy unit (ITU) for non‐COVID reasons. We demonstrate a higher frequency of autoantibodies in the COVID‐19 ITU group compared with non‐COVID‐19 ITU disease control patients and that autoantibodies were also found in the serum 3–5 months post‐COVID‐19 infection. Non‐COVID patients displayed a diverse pattern of autoantibodies; in contrast, the COVID‐19 groups had a more restricted panel of autoantibodies including skin, skeletal muscle and cardiac antibodies. Our results demonstrate that respiratory viral infection with SARS‐CoV‐2 is associated with the detection of a limited profile of tissue‐specific autoantibodies, detectable using routine clinical immunology assays. Further studies are required to determine whether these autoantibodies are specific to SARS‐CoV‐2 or a phenomenon arising from severe viral infections and to determine the clinical significance of these autoantibodies. [ABSTRACT FROM AUTHOR]

Background: Immunologists are increasingly being asked to assess patients with non-classical and secondary antibody deficiency to determine their potential need for immunoglobulin replacement therapy (IGRT). Immunoglobulin is a limited, expensive resource and no clear guidance exists for this broad patient group. The purpose of this survey is to establish what factors influence the decision to commence IGRT in adult patients, when diagnostic criteria for primary antibody deficiency are not fulfilled.Methods: Under the auspices of the United Kingdom Primary Immunodeficiency Network (UKPIN), a study group was established which circulated an online questionnaire to the consultant body across the UK and Ireland. Results provided a snapshot of the current clinical practice of 71% of consultant immunologists, from 30 centers.Results: In order of importance, factors which influence the decision to commence IGRT include number of hospital admissions with infection, serum IgG level, bronchiectasis, radiologically proven pneumonia, number of positive sputum cultures, number of antibiotic courses, and results of immunization studies. The commonest test vaccine used was Pneumovax 23 with measurement of serotype-specific responses at 4 weeks, with a threshold of 0.35 μg/ml in 2/3 of serotypes measured. Eighty-six percent of patients are treated with a trial of prophylactic antibiotics prior to consideration of IGRT. Efficacy of IGRT trial is assessed at between 6 and 12 months.Conclusions: There was consistency in clinical practice using a combination of clinical history, evidence of infections, and vaccination testing for diagnosis. However, there was some variation in the implementation of this practice, particularly in vaccine choice and assessment of response to vaccination. [ABSTRACT FROM AUTHOR]

We describe the case of a 34-year-old gentleman investigated for persistent neutropaenia following two episodes of pneumonia. Specialist investigations led to the diagnosis of multiple myeloma (MM) producing a truncated monoclonal γ3 heavy chain (HC) immunoglobulin molecule unattached to a light chain (LC) with atypical features for both MM and HC disease. Western blot showed γ3HC was truncated with a large deletion (75 kDa). Flow cytometry of the bone marrow aspirate revealed an unusual staining pattern. This plasma cell dyscrasia was also unusual in that a subpopulation (30%) secreted large quantities of free LC (FLC) as well as truncated IgG HC. This is the first description, investigation and treatment of MM with a plasma cell population producing truncated γ3HC and κFLC M-proteins and illustrates a number of unique immunological and clinical features. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Lung cancer is the leading cause of cancer-related death worldwide. Surgical resection remains the definitive curative treatment for early-stage disease offering an overall 5-year survival rate of 62%. Despite careful case selection, a significant proportion of early-stage cancers relapse aggressively within the first year post-operatively. Identification of these patients is key to accurate prognostication and understanding the biology that drives early relapse might open up potential novel adjuvant therapies.Methods: We performed an unsupervised interrogation of >1600 serum-based autoantibody biomarkers using an iterative machine-learning algorithm.Results: We identified a 13 biomarker signature that was highly predictive for survivorship in post-operative early-stage lung cancer; this outperforms currently used autoantibody biomarkers in solid cancers. Our results demonstrate significantly poor survivorship in high expressers of this biomarker signature with an overall 5-year survival rate of 7.6%.Conclusions: We anticipate that the data will lead to the development of an off-the-shelf prognostic panel and further that the oncogenic relevance of the proteins recognised in the panel may be a starting point for a new adjuvant therapy. [ABSTRACT FROM AUTHOR]

Background: The striking increase in COVID-19 severity in older adults provides a clear example of immunesenescence, the age-related remodelling of the immune system. To better characterise the association between convalescent immunesenescence and acute disease severity, we determined the immune phenotype of COVID-19 survivors and non-infected controls. Results: We performed detailed immune phenotyping of peripheral blood mononuclear cells isolated from 103 COVID-19 survivors 3–5 months post recovery who were classified as having had severe (n = 56; age 53.12 ± 11.30 years), moderate (n = 32; age 52.28 ± 11.43 years) or mild (n = 15; age 49.67 ± 7.30 years) disease and compared with age and sex-matched healthy adults (n = 59; age 50.49 ± 10.68 years). We assessed a broad range of immune cell phenotypes to generate a composite score, IMM-AGE, to determine the degree of immune senescence. We found increased immunesenescence features in severe COVID-19 survivors compared to controls including: a reduced frequency and number of naïve CD4 and CD8 T cells (p < 0.0001); increased frequency of EMRA CD4 (p < 0.003) and CD8 T cells (p < 0.001); a higher frequency (p < 0.0001) and absolute numbers (p < 0.001) of CD28−ve CD57+ve senescent CD4 and CD8 T cells; higher frequency (p < 0.003) and absolute numbers (p < 0.02) of PD-1 expressing exhausted CD8 T cells; a two-fold increase in Th17 polarisation (p < 0.0001); higher frequency of memory B cells (p < 0.001) and increased frequency (p < 0.0001) and numbers (p < 0.001) of CD57+ve senescent NK cells. As a result, the IMM-AGE score was significantly higher in severe COVID-19 survivors than in controls (p < 0.001). Few differences were seen for those with moderate disease and none for mild disease. Regression analysis revealed the only pre-existing variable influencing the IMM-AGE score was South Asian ethnicity (β = 0.174, p = 0.043), with a major influence being disease severity (β = 0.188, p = 0.01). Conclusions: Our analyses reveal a state of enhanced immune ageing in survivors of severe COVID-19 and suggest this could be related to SARS-Cov-2 infection. Our data support the rationale for trials of anti-immune ageing interventions for improving clinical outcomes in these patients with severe disease. [ABSTRACT FROM AUTHOR]

Post-acute cardiac sequelae, following SARS-CoV-2 infection, are well recognized as complications of COVID-19. We have previously shown the persistence of autoantibodies against antigens in skin, muscle, and heart in individuals following severe COVID-19; the most common staining on skin tissue displayed an inter-cellular cement pattern consistent with antibodies against desmosomal proteins. Desmosomes play a critical role in maintaining the structural integrity of tissues. For this reason, we analyzed desmosomal protein levels and the presence of anti-desmoglein (DSG) 1, 2, and 3 antibodies in acute and convalescent sera from patients with COVID-19 of differing clinical severity. We find increased levels of DSG2 protein in sera from acute COVID-19 patients. Furthermore, we find that DSG2 autoantibody levels are increased significantly in convalescent sera following severe COVID-19 but not in hospitalized patients recovering from influenza infection or healthy controls. Levels of autoantibody in sera from patients with severe COVID-19 were comparable to levels in patients with non-COVID-19-associated cardiac disease, potentially identifying DSG2 autoantibodies as a novel biomarker for cardiac damage. To determine if there was any association between severe COVID-19 and DSG2, we stained post-mortem cardiac tissue from patients who died from COVID-19 infection. This confirmed DSG2 protein within the intercalated discs and disruption of the intercalated disc between cardiomyocytes in patients who died from COVID-19. Our results reveal the potential for DSG2 protein and autoimmunity to DSG2 to contribute to unexpected pathologies associated with COVID-19 infection. We find raised levels of anti-DSG2 autoantibodies in sera from individuals following severe COVID-19. Staining of post-mortem cardiac tissue from individuals that died from COVID-19 with an anti-DSG2 antibody revealed disruption of the intercalated disc between cardiomyocytes that was consistent with separation of the DSG2 protein homodimer. Our results reveal the potential for DSG2 protein and autoimmunity to DSG2 to contribute to unexpected pathologies associated with COVID-19 infection. [ABSTRACT FROM AUTHOR]

Objectives: Patients with Systemic Lupus Erythematosus are known to have dysregulated immune responses and may have reduced response to vaccination against COVID-19 while being at risk of severe COVID-19 disease. The aim of this study was to identify whether vaccine responses were attenuated in SLE and to assess disease- and treatment-specific associations. Methods: Patients with SLE were matched by age, sex and ethnic background to healthcare worker healthy controls (HC). Anti-SARS-CoV-2 spike glycoprotein antibodies were measured at 4–8 weeks following the second COVID-19 vaccine dose (either BNT162b2 or ChAdOx1 nCoV-19) using a CE-marked combined ELISA detecting IgG, IgA and IgM (IgGAM). Antibody levels were considered as a continuous variable and in tertiles and compared between SLE patients and HC and associations with medication, disease activity and serological parameters were determined. Results: Antibody levels were lower in 43 SLE patients compared to 40 HC (p < 0.001). There was no association between antibody levels and medication, lupus disease activity, vaccine type or prior COVID infection. Higher serum IgA, but not IgG or IgM, was associated with being in a higher anti-SARS-CoV-2 antibody level tertile (OR [95% CI] 1.820 [1.050, 3.156] p = 0.033). Similarly, higher lymphocyte count was also associated with being in a higher tertile of anti-SARS-CoV-2 (OR 3.330 [1.505, 7.366] p = 0.003) Conclusion: Patients with SLE have lower antibody levels following 2 doses of COVID-19 vaccines compared to HC. In SLE lower lymphocyte counts and serum IgA levels are associated with lower antibody levels post vaccination, potentially identifying a subgroup of patients who may therefore be at increased risk of infection. [ABSTRACT FROM AUTHOR]

In this population-based cohort of 7538 adults, combined immunoglobulin (Ig) G, IgA, and IgM (IgG/A/M) anti-spike titers measured after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination were predictive of protection against breakthrough SARS-CoV-2 infection. Discrimination was significantly improved by adjustment for factors influencing risk of SARS-CoV-2 exposure, including household overcrowding, public transport use, and visits to indoor public places. Anti-spike IgG/A/M titers showed positive correlation with neutralizing antibody titers (rs = 0.80 [95% confidence interval, .72-.86]; P < .001) and S peptide-stimulated interferon-γ concentrations (rs = 0.31 [.13-.47]; P < .001). [ABSTRACT FROM AUTHOR]

Aims Thrombotic complications and vasculopathy have been extensively associated with severe COVID-19 infection; however, the mechanisms inducing endotheliitis and the disruption of endothelial integrity in the microcirculation are poorly understood. We hypothesized that within the vessel wall, pericytes preferentially take up viral particles and mediate the subsequent loss of vascular integrity. Methods and results Immunofluorescence of post-mortem patient sections was used to assess pathophysiological aspects of COVID-19 infection. The effects of COVID-19 on the microvasculature were assessed using a vascular organoid model exposed to live viral particles or recombinant viral antigens. We find increased expression of the viral entry receptor angiotensin-converting enzyme 2 on pericytes when compared to vascular endothelium and a reduction in the expression of the junctional protein CD144, as well as increased cell death, upon treatment with both live virus and/or viral antigens. We observe a dysregulation of genes implicated in vascular permeability, including Notch receptor 3, angiopoietin-2, and TEK. Activation of vascular organoids with interleukin-1β did not have an additive effect on vascular permeability. Spike antigen was detected in some patients' lung pericytes, which was associated with a decrease in CD144 expression and increased platelet recruitment and von Willebrand factor (VWF) deposition in the capillaries of these patients, with thrombi in large vessels rich in VWF and fibrin. Conclusion Together, our data indicate that direct viral exposure to the microvasculature modelled by organoid infection and viral antigen treatment results in pericyte infection, detachment, damage, and cell death, disrupting pericyte-endothelial cell crosstalk and increasing microvascular endothelial permeability, which can promote thrombotic and bleeding complications in the microcirculation. [ABSTRACT FROM AUTHOR]

The article offers an overview of the diagnosis and management of immunoglobulin G4 (IgG4)-related disease, a multisystem fibroinflammatory disease that can process to organ failure if left untreated. Topics include the pathophysiologic mechanisms involved in IgG4-related disease, the geoepidemiology of the disease, and diagnosis which include routine blood tests, immunologic blood tests, and histologic assessment. The sensitivity of IgG4-related disease to glucocorticoid therapy is noted.

Background: Prospective population-based studies investigating multiple determinants of pre-vaccination antibody responses to SARS-CoV-2 are lacking. Methods: We did a prospective population-based study in SARS-CoV-2 vaccine-naive UK adults recruited between May 1 and November 2, 2020, without a positive swab test result for SARS-CoV-2 prior to enrolment. Information on 88 potential sociodemographic, behavioural, nutritional, clinical and pharmacological risk factors was obtained through online questionnaires, and combined IgG/IgA/IgM responses to SARS-CoV-2 spike glycoprotein were determined in dried blood spots obtained between November 6, 2020, and April 18, 2021. We used logistic and linear regression to estimate adjusted odds ratios (aORs) and adjusted geometric mean ratios (aGMRs) for potential determinants of SARS-CoV-2 seropositivity (all participants) and antibody titres (seropositive participants only), respectively. Results: Of 11,130 participants, 1696 (15.2%) were seropositive. Factors independently associated with higher risk of SARS-CoV-2 seropositivity included frontline health/care occupation (aOR 1.86, 95% CI 1.48–2.33), international travel (1.20, 1.07–1.35), number of visits to shops and other indoor public places (≥ 5 vs. 0/week: 1.29, 1.06–1.57, P-trend = 0.01), body mass index (BMI) ≥ 25 vs. < 25 kg/m2 (1.24, 1.11–1.39), South Asian vs. White ethnicity (1.65, 1.10–2.49) and alcohol consumption ≥15 vs. 0 units/week (1.23, 1.04–1.46). Light physical exercise associated with lower risk (0.80, 0.70–0.93, for ≥ 10 vs. 0–4 h/week). Among seropositive participants, higher titres of anti-Spike antibodies associated with factors including BMI ≥ 30 vs. < 25 kg/m2 (aGMR 1.10, 1.02–1.19), South Asian vs. White ethnicity (1.22, 1.04–1.44), frontline health/care occupation (1.24, 95% CI 1.11–1.39), international travel (1.11, 1.05–1.16) and number of visits to shops and other indoor public places (≥ 5 vs. 0/week: 1.12, 1.02–1.23, P-trend = 0.01); these associations were not substantially attenuated by adjustment for COVID-19 disease severity. Conclusions: Higher alcohol consumption and lower light physical exercise represent new modifiable risk factors for SARS-CoV-2 infection. Recognised associations between South Asian ethnic origin and obesity and higher risk of SARS-CoV-2 seropositivity were independent of other sociodemographic, behavioural, nutritional, clinical, and pharmacological factors investigated. Among seropositive participants, higher titres of anti-Spike antibodies in people of South Asian ancestry and in obese people were not explained by greater COVID-19 disease severity in these groups. [ABSTRACT FROM AUTHOR]

There are limited treatments for severe COVID-19; of the empirical treatments used in this study (dexamethasone, remdesivir, convalescent plasma), the only dexamethasone is associated with reduced 28-day mortality in the general population [[3]-[5]]. Herein, we highlight our experience of using remdesivir and convalescent plasma to treat persistent symptomatic COVID-19 in a patient with secondary immunodeficiency following long-term rituximab treatment. To the Editor, We read with interest the report from London et al. regarding the efficacy of convalescent plasma in the treatment of severe COVID-19 in two patients with primary immunodeficiencies [[1]]. The efficacy of convalescent plasma in the treatment of COVID-19 in patients has been reported in small case series of individuals with both congenital and acquired B cell aplasia [[7]-[9]]. [Extracted from the article]

Dried blood spot (DBS) samples can be used for the detection of severe acute respiratory syndrome coronavirus 2 spike antibodies. DBS sampling is comparable to matched serum samples with a relative 98.1% sensitivity and 100% specificity. Thus, DBS sampling offers an alternative for population-wide serologic testing in the coronavirus pandemic. [ABSTRACT FROM AUTHOR]

Children were relatively spared during COVID-19 pandemic. However, the recently reported hyperinflammatory syndrome with overlapping features of Kawasaki disease and toxic shock syndrome—"Paediatric Inflammatory Multisystem Syndrome-temporally associated with SARS-CoV-2" (PIMS-TS) has caused concern. We describe cardiac findings and short-term outcomes in children with PIMS-TS at a tertiary children's hospital. Single-center observational study of children with PIMS-TS from 10th April to 9th May 2020. Data on ECG and echocardiogram were retrospectively analyzed along with demographics, clinical features and blood parameters. Fifteen children with median age of 8.8 (IQR 6.4–11.2) years were included, all were from African/Afro-Caribbean, South Asian, Mixed or other minority ethnic groups. All showed raised inflammatory/cardiac markers (CRP, ferritin, Troponin I, CK and pro-BNP). Transient valve regurgitation was present in 10 patients (67%). Left Ventricular ejection fraction was reduced in 12 (80%), fractional shortening in 8 (53%) with resolution in all but 2. Fourteen (93%) had coronary artery abnormalities, with normalization in 6. ECG abnormalities were present in 9 (60%) which normalized in 6 by discharge. Ten (67%) needed inotropes and/or vasopressors. None needed extracorporeal life support. Improvement in cardiac biochemical markers was closely followed by improvement in ECG/echocardiogram. All patients were discharged alive and twelve (80%) have been reviewed since. Our entire cohort with PIMS-TS had cardiac involvement and this degree of involvement is significantly more than other published series and emphasizes the need for specialist cardiac review. We believe that our multi-disciplinary team approach was crucial for the good short-term outcomes. [ABSTRACT FROM AUTHOR]

Summary: Monoclonal gammopathy of undetermined significance (MGUS) affects 3·2% of adults aged >50 years. MGUS carries a life‐long risk of progression to multiple myeloma and causes complications including infection and renal impairment; common causes of hospital admission. This study aimed to assess MGUS prevalence in emergency medical hospital admissions. Patients were recruited from unselected emergency medical admissions in a hospital in the United Kingdom. Serum protein electrophoresis was performed, with immunofixation of abnormal results. Reason for admission and routine test results were recorded. After education about MGUS and myeloma, patients chose whether they wished to be informed of new diagnoses. A total of 660 patients were tested and 35 had a paraprotein suggestive of MGUS. The overall rate of MGUS was 5·3%. MGUS prevalence in those aged >50 years was 6·94%, higher than the previously published rate of 3·2% (P < 0·0005). There were higher rates in those with chronic kidney disease (13·75% vs. 4·14%, P = 0·002), heart failure (14% vs. 4·59%, P = 0·012), anaemia (8·96% vs. 3·41%, P = 0·003) or leucocytosis (9·33% vs. 3·04%, P = 0·002). In all, 96% of patients wished to be informed of their screening results. The prevalence of MGUS in emergency hospital admissions is higher than expected based on previous population‐based rates. This may suggest a selected population for screening. [ABSTRACT FROM AUTHOR]

The article focuses on a research related to presence of poor functional antibody responses in patients with chronic lymphocytic leukaemia (CLL). Topics discussed include high risks of CLL due to development of secondary immunodeficiency, use of total immunoglobulin G (IgG) concentration as an indicator of antibody deficiency, and suggestion towards enhanced vaccine regimens and prophylactic antibiotics to reduce mortality of infection in CLL.

[Display omitted] • HexaPro and 2P are recombinant glycoprotein versions of SARS-CoV-2 spike (S). • HexaPro is an expression-enhanced version of SARS-CoV-2 S protein. • Compared to 2P, HexaPro exhibits localised perturbations in glycosylation. • Binding of antibodies from COVID-19 patients was insensitive to the glycoform of S. • These results suggests that variations in S protein glycosylation will not impact serological studies. Extensive glycosylation of viral glycoproteins is a key feature of the antigenic surface of viruses and yet glycan processing can also be influenced by the manner of their recombinant production. The low yields of the soluble form of the trimeric spike (S) glycoprotein from SARS-CoV-2 has prompted advances in protein engineering that have greatly enhanced the stability and yields of the glycoprotein. The latest expression-enhanced version of the spike incorporates six proline substitutions to stabilize the prefusion conformation (termed SARS-CoV-2 S HexaPro). Although the substitutions greatly enhanced expression whilst not compromising protein structure, the influence of these substitutions on glycan processing has not been explored. Here, we show that the site-specific N-linked glycosylation of the expression-enhanced HexaPro resembles that of an earlier version containing two proline substitutions (2P), and that both capture features of native viral glycosylation. However, there are site-specific differences in glycosylation of HexaPro when compared to 2P. Despite these discrepancies, analysis of the serological reactivity of clinical samples from infected individuals confirmed that both HexaPro and 2P protein are equally able to detect IgG, IgA, and IgM responses in all sera analysed. Moreover, we extend this observation to include an analysis of glycan engineered S protein, whereby all N-linked glycans were converted to oligomannose-type and conclude that serological activity is not impacted by large scale changes in glycosylation. These observations suggest that variations in glycan processing will not impact the serological assessments currently being performed across the globe. [ABSTRACT FROM AUTHOR]

A Correction to this paper has been published: https://doi.org/10.1007/s10875-021-01029-z [ABSTRACT FROM AUTHOR]