Disparate kinetics in immune response of two different Haemophilus influenzae type b conjugate vaccines: Immunogenicity and safety observations from a randomized controlled phase IV study in healthy infants and toddlers using a 2+1 schedule.

Since the introduction of Haemophilus Influenzae type b (Hib) conjugate vaccines, invasive Hib disease has strongly declined worldwide, yet continued control of Hib disease remains important. In Europe, currently three different hexavalent combination vaccines containing Hib conjugates are marketed. In this phase IV, single-blind, randomized, controlled, multi-country study (NCT04535037), we aimed to compare, in a 2 + 1 vaccination schedule, the immunogenicity and safety and show non-inferiority, as well as superiority, of DTPa-HBV-IPV/Hib (Ih group) versus DTaP5-HB-IPV-Hib (Va group) in terms of anti-polyribosylribitol phosphate (PRP) antibody geometric mean concentrations (GMCs) and proportion of participants reaching anti-PRP antibody concentrations greater than or equal to a threshold of 5 µg/mL. One month after the booster vaccination, the anti-PRP antibody GMC ratio (Ih group/Va group) was 0.917 (95% CI: 0.710-1.185), meeting the non-inferiority criteria. The difference in percentage of participants (Ih group - Va group) reaching GMCs ≥5 µg/mL was -6.3% (95% CI: -14.1% to 1.5%), not reaching the predefined non-inferiority threshold. Interestingly, a slightly higher post-booster antibody avidity was observed in the Ih group versus the Va group. Both vaccines were well tolerated, and no safety concerns were raised. This study illustrates the different kinetics of the anti-PRP antibody response post-primary and post-booster using the two vaccines containing different Hib conjugates and indicates a potential differential impact of concomitant vaccinations on the anti-PRP responses. The clinical implications of these differences should be further studied.

Vaccination against Haemophilus influenzae type b (Hib) is included in the majority of national immunization programs worldwide and has shown to be effective in preventing Hib disease. In Europe, different vaccines containing Hib components are marketed. We compared the immune response and safety of 2 of these (DTPa-HBV-IPV/Hib, Ih group) and DTaP5-HB-IPV-Hib, Va group) in infants and toddlers, when used in a 2 + 1 schedule, i.e. two primary vaccination doses (at 2 and 4 months of age of the infant), followed by one booster dose at the age of one year. One month after the booster vaccination, the antibody concentration ratio between both groups (Ih group/Va group) was 0.917 (95% CI: 0.710­1.185) showing the DTPa-HBV-IPV/Hib vaccine was non-inferior to the DTaP5-HB-IPV-Hib vaccine; the difference in percentage of participants (Ih group ­ Va group) with antibody concentrations above 5 µg/mL was -6.3% (95% CI: −14.1% to 1.5%), which did not meet the pre-defined criterion for non-inferiority. In the Ih group, the quality of antibodies produced was somewhat higher versus the Va group. Both vaccines were well tolerated, and no safety concerns were raised. The kinetics of the immune response are different between the 2 vaccines. Since both vaccines contain different additional components (conjugated proteins), a possible effect of concomitant (simultaneously administered) vaccines was studied. Further investigations to confirm our findings are needed.

Comparison of ex vivo bioluminescence imaging, Alu-qPCR and histology for the quantification of spontaneous lung and bone metastases in subcutaneous xenograft mouse models.

Bioluminescence imaging (BLI) is a non-invasive state-of-the-art-method for longitudinal tracking of tumor cells in mice. The technique is commonly used to determine bone metastatic burden in vivo and also suitable ex vivo to detect even smallest bone micro-metastases in spontaneous metastasis xenograft models. However, it is unclear to which extent ex vivo BLI correlates with alternative methods for metastasis quantification. Here, we compared ex vivo BLI, human DNA-based Alu-qPCR, and histology for the quantification of bone vs. lung metastases, which are amongst the most common sites of metastasis in prostate cancer (PCa) patients and spontaneous PCa xenograft models. Data from 93 immunodeficient mice were considered, each of which were subcutaneously injected with luciferase/RGB-labeled human PCa PC-3 cells. The primary tumors were resected at ~ 0.75 cm³ and mice were sacrificed ~ 3 weeks after surgery and immediately examined by ex vivo BLI. Afterwards, the right lungs and hind limbs with the higher BLI signal (BLIHi bone) were processed for histology, whereas the left lung lobes and hind limbs with the lower BLI signal (BLILo bone) were prepared for Alu-qPCR. Our data demonstrate remarkable differences in the correlation coefficients of the different methods for lung metastasis detection (r ~ 0.8) vs. bone metastasis detection (r ~ 0.4). However, the BLI values of the BLIHi and BLILo bones correlated very strongly (r ~ 0.9), indicating that the method per se was reliable under identical limitations; the overall level of metastasis to contralateral bones was astonishingly similar. Instead, the level of lung metastasis only weakly to moderately correlated with the level of bone metastasis formation. Summarized, we observed a considerable discrepancy between ex vivo BLI and histology/Alu-qPCR in the quantification of bone metastases, which was not observed in the case of lung metastases. Future studies using ex vivo BLI for bone metastasis quantification should combine multiple methods to accurately determine metastatic load in bone samples.

Clinical Validity of Anti-Proteinase 3 Antibodies in Patients with Inflammatory Bowel Disease: A Short Meta-Analysis.

Anti-neutrophil cytoplasmic antibodies (ANCA) directed to proteinase 3 (PR3) represent highly established markers for patients with ANCA-associated vasculitis (AAV). PR3-ANCA have also demonstrated utility in the management of inflammatory bowel disease (IBD). More specifically, PR3-ANCA discriminate individuals with ulcerative colitis (UC) from Crohn's disease (CD) patients and are associated with disease severity, activity, and treatment non-response. Here, we aim to summarize the current data on the diagnostic utility of PR3-ANCA in IBD. A structured, systematic literature review, including three electronic databases, was conducted on June 6th, 2023, to identify studies assessing the diagnostic accuracy of the QUANTA Flash® PR3 assay in UC vs. CD patients. Electronic searches were supplemented by hand searching. A hierarchical, bivariate, mixed-effect meta-analysis was conducted using the metandi function, as per the Cochrane collaboration recommendations. Study quality was assessed using the QUADAS-2 tool, which considers the risk of bias and applicability. Six out of a hundred and eleven citations met the inclusion criteria and reported QUANTA Flash® PR3 diagnostic accuracy in UC vs. CD (UC, n = 667, CD, n = 682 patients). The sensitivity/specificity point estimate for UC was 34.9%/95.9%. This resulted in a Diagnostic Odds Ratio (DOR) of 12.6. The risk of bias was low in the index test and reference standard domains. Four of the six studies (67%) showed an unclear risk of bias in patient selection and in flow and timing domains. All studies had low concerns about applicability in all the domains. PR3-ANCA measured with the QUANTA Flash® PR3 assay represent novel diagnostic markers in IBD and enables discrimination between UC and CD.

Safety and immunogenicity of co-administered meningococcal serogroup B (4CMenB) vaccine: A literature review.

The four-component meningococcal serogroup B vaccine (4CMenB) is indicated for the prevention of invasive meningococcal disease (IMD) caused by Neisseria meningitidis serogroup B. Co-administering 4CMenB with other vaccines may improve vaccine uptake provided that the safety and immunogenicity of either are not affected. Published literature on the immunogenicity and reactogenicity of 4CMenB co-administered with other routine childhood and adulthood vaccines was reviewed. From 282 publications identified, data were collated from 10 clinical studies, 3 real-world studies, and 3 reviews. The evidence showed that 4CMenB co-administration is not associated with significant safety concerns or clinically relevant immunological interferences. The increased reactogenicity (e.g., fever) associated with 4CMenB co-administration can be adequately managed with prophylactic paracetamol in children. Thus, 4CMenB co-administration has the potential to maximize vaccine coverage and improve protection against IMD globally.

Machine Learning in Antibody Diagnostics for Inflammatory Bowel Disease Subtype Classification.

Antibody testing in inflammatory bowel disease (IBD) can add to diagnostic accuracy of the main subtypes Crohn's disease (CD) and ulcerative colitis (UC). Whether modern modeling techniques such as supervised and unsupervised machine learning are of value for finer distinction of subtypes such as IBD-unclassified (IBD-U) is not known. We determined the antibody profile of 100 adult IBD patients from the Swiss IBD cohort study with known subtype (50 CD, 50 UC) as well as of 76 IBD-U patients. We included ASCA IgG and IgA, p-ANCA, MPO- and PR3-ANCA, and xANCA measurements for computing different antibody panels as well as machine learning models. The AUC of an optimized antibody panel was 85% (95%CI, 78-92%) to distinguish CD from UC patients. The antibody profile of IBD-U patients was closely related to UC. No specific antibody profile was predictive for IBD-U nor for re-classification. The panel diagnostic was in favor of UC reclassification prediction with a correct assignment rate of 69.2-73.1% depending on the cut-off applied. Supervised machine learning could not distinguish between CD, UC, and IBD-U. More so, unsupervised machine learning suggested only two distinct clusters as a likely number of IBD subtypes. Antibodies in IBD are supportive in confirming clinical determined subtypes CD and UC but have limited capacity to predict IBD-U and reclassification during follow-up. In terms of antibody profiles, IBD-U is not a distinct subtype of IBD.

Safety and Tolerability of V114 Pneumococcal Vaccine in Infants: A Phase 3 Study.

BACKGROUND AND OBJECTIVES: Disease caused by Streptococcus pneumoniae is associated with considerable morbidity and mortality in children. Pneumococcal conjugate vaccines (PCVs) are well tolerated and effective at reducing pneumococcal disease caused by vaccine serotypes. VAXNEUVANCE (V114) is a 15-valent PCV containing 13 serotypes in Prevnar 13 (PCV13), plus serotypes 22F and 33F. This large phase 3 study evaluated safety and tolerability of V114 in infants. METHODS: In total, 2409 infants were randomized to receive V114 or PCV13 at 2, 4, 6, and 12 to 15 months of age. Safety was evaluated as the proportion of participants with adverse events (AEs). Solicited and unsolicited injection-site and systemic AEs were collected for 14 days after each study vaccination, and serious AEs up to 6 months after the last PCV dose. RESULTS: The proportions of participants with injection-site, systemic, vaccine-related, and serious AEs were generally comparable between recipients of V114 and PCV13. The most frequently reported AEs were solicited, with irritability and somnolence being the most frequent in both groups. Although the incidence of some AEs was higher in the V114 group, the between-group differences were small. The majority of experienced AEs were of mild-to-moderate intensity and lasted ≤3 days. There were 2 vaccine-related serious AEs of pyrexia in the V114 group, and 2 nonvaccine-related deaths, 1 in each group. No participant discontinued study vaccine because of AEs. CONCLUSIONS: V114 is well tolerated and has a generally comparable safety profile to that of PCV13. These study results support routine use of V114 in infants.

Understanding barriers to vaccination against invasive meningococcal disease: a survey of the knowledge gap and potential solutions.

INTRODUCTION: Invasive meningococcal disease (IMD) is a leading cause of life-threatening bacterial meningitis and septicemia. Evidence points to a knowledge gap among parents, teenagers, and healthcare providers (HCPs) regarding IMD and available vaccines, including those against the highly prevalent serogroup B. AREAS COVERED: An online survey was conducted between March 27 and 12 April 2019, to gather insights into the knowledge that parents/guardians have about IMD vaccines. The children were aged 2 months to 10 years in Australia, Brazil, Germany, Greece, Italy, and Spain, 5-20 years in the UK, and 16-23 years in the USA. The findings were discussed in the context of the available literature and solutions were proposed to minimize the knowledge gap and the barriers to vaccination against IMD. EXPERT OPINION: The survey demonstrated that parents have a good understanding of IMD but a limited understanding of the different serogroups and vaccines. The available literature highlighted multiple barriers to IMD vaccine uptake; these may be reduced through education of HCPs, clear recommendations to parents by HCPs, the use of technology, and disease-awareness initiatives that engage parents through physical and digital channels. Further studies are warranted to assess the impact of the COVID-19 pandemic on IMD vaccination.

Pandemic's influence on parents' attitudes and behaviors toward meningococcal vaccination.

Invasive meningococcal disease is a life-threatening infection preventable through vaccination. Pediatric vaccination rates have declined during the coronavirus disease 2019 (COVID-19) pandemic. This survey aimed to understand how parents' attitudes and behaviors have changed during the pandemic with regard to immunization and, more specifically, meningococcal vaccination. An online survey was emailed to parents of eligible children 0-4 years, following the selection process from UK, France, Germany, Italy, Brazil, Argentina, and Australia; and of adolescents 11-18 years from US. Data collection took place 19 January-16 February 2021. Quotas were set to ensure a representative sample. Eleven questions relating to general perceptions around vaccination and attitudes and behaviors toward meningitis vaccination were displayed. On 4,962 parents (average 35 years) participating in the survey, most (83%) believed important for their child to continue receiving recommended vaccines during the COVID-19 pandemic. Nearly half of routine vaccine appointments were delayed or canceled due to the pandemic, and 61% of respondents were likely to have their children catch up once COVID-19 restrictions were lifted. 30% of meningitidis vaccination appointments were canceled or delayed during the pandemic, and 21% of parents did not intend to reschedule them because of lockdown/stay at home regulations, and fear of catching COVID-19 in public places. It is crucial to communicate clear instructions to health workers and the general population and to provide appropriate safety precautions in vaccination centers. This will help to maintain vaccination rates and limit infections to prevent future outbreaks.

What is the context? Invasive meningococcal disease (IMD) is an uncommon infection that can lead to permanent disabilities and even death.Meningitis vaccination can prevent IMDs caused by Neisseria meningitidis.Vaccination rates have declined during the coronavirus (COVID-19) pandemic.What is new? We collected opinion of parents from the UK, France, Germany, Italy, Brazil, Argentina, Australia, and the US, to understand their attitudes and behaviors toward meningitis vaccination during the COVID-19 pandemic.Results were reviewed by health care professional experts as well as by patient authors (IMD survivors).Most (83%) of the 4,962 parents believed that it is important for their child to continue receiving recommended vaccines during the COVID-19 pandemic.Half of the scheduled appointments for meningitis vaccination were canceled or delayed during the COVID-19 pandemic, mainly due to lockdown regulations and fear of catching COVID-19.Twenty-one percent of the parents who had their child's meningitis vaccination appointment canceled, did not intend to reschedule it.What is the impact? It is crucial that clear information is communicated by health care authorities and practitioners about the availability of vaccination during pandemic and the safety precautions that are taken.Collected opinions emphasize the importance of continuing vaccinations against infectious diseases during a pandemic.

[CME: Rational Laboratory Diagnostics in the Context of COVID-19]. / CME: Rationale Labordiagnostik im Kontext von COVID-19.

CME: Rational Laboratory Diagnostics in the Context of COVID-19 Abstract. In the management of COVID-19, a variety of laboratory tests are available to the general practitioner. The choice is difficult, and some of these laboratory tests are discussed controversially in the lay press. In this article, we discuss the important clinical questions and the contribution of laboratory tests to answering these questions. We describe the most common test principles and discuss their diagnostic value. In doing so, we provide the practicing physician with a simple overview for the clinical practice.

Humoral response to mRNA vaccines against SARS-CoV-2 in patients with humoral immunodeficiency disease.

OBJECTIVES: Although mRNA-based vaccines against SARS-CoV-2 induce a robust immune response and prevent infections and hospitalizations, there are limited data on the antibody response in individuals with humoral immunodeficiency. The aim of this study was to evaluate the humoral immune response after two vaccine doses with BNT162b2 or mRNA-1273 in patients with humoral immunodeficiency disease. METHODS: This cross-sectional study assessed 39 individuals with hypogammaglobulinemia under immunoglobulin replacement therapy. IgG anti-SARS-CoV-2 spike protein antibodies (anti-S) were measured 4 weeks to 4 months after two doses of an mRNA vaccine against SARS-CoV-2. The proportion of patients, who developed a humoral immune response to the spike protein were evaluated and compared to 19 healthy controls. RESULTS: After vaccination with two vaccine doses, 26/39 patients (66.7%) with humoral immunodeficiency disease and all healthy controls developed anti-S. In subjects with baseline IgG <3 g/l, only 1/5 (20%) showed a humoral immune response. 10 out of 26 with CVID (38.5%) and 7/9 under immunosuppressive drugs (77.8%) developed no immune response (13 subjects with no response) compared to 0/19 in healthy controls. Subgroup analysis in patients without immunosuppressive drugs revealed lower anti-S in patients with moderate to severe humoral immunodeficiency disease: baseline IgG <3 g/l: 12.0 AU/ml (95%CI 12.0-125.0), baseline IgG 3-5 g/l: 99.9 AU/ml (95%CI 14.4-400.0), baseline IgG >5 g/l: 151.5 AU/ml (95%CI 109.0-400.0), healthy controls 250.0 AU/ml (95%CI 209.0-358.0), p = 0.007. CONCLUSION: In most patients with mild to moderate humoral immunodeficiency we found only slightly lower anti-S antibodies compared with healthy controls after two vaccine doses with BNT162b2 and mRNA-1273. However, in patients with a decreased baseline IgG below 3 g/l and/or under immunosuppressive drugs, we found severely impaired humoral immune responses.

Trajectories of humoral and cellular immunity and responses to a third dose of mRNA vaccines against SARS-CoV-2 in patients with a history of anti-CD20 therapy.

BACKGROUND: The majority of patients with B-cell-depleting therapies show compromised vaccination-induced immune responses. Herein, we report on the trajectories of anti-SARS-CoV-2 immune responses in patients of the RituxiVac study compared with healthy volunteers and investigate the immunogenicity of a third vaccination in previously humoral non-responding patients. METHODS: We investigated the humoral and cell-mediated immune response after SARS-CoV-2 messanger RNA vaccination in patients with a history with anti-CD20 therapies. Coprimary outcomes were antispike and SARS-CoV-2-stimulated interferon-γ concentrations in vaccine responders 4.3 months (median; IQR: 3.6-4.8 months) after first evaluation, and humoral and cell-mediated immunity (CMI) after a third vaccine dose in previous humoral non-responders. Immunity decay rates were compared using analysis of covariance in linear regression. RESULTS: 5.6 months (IQR: 5.1-6.7) after the second vaccination, we detected antispike IgG in 88% (29/33) and CMI in 44% (14/32) of patients with a humoral response after two-dose vaccination compared with 92% (24/26) healthy volunteers with antispike IgG and 69% (11/16) with CMI 6.8 months after the second vaccination (IQR: 6.0-7.1). Decay rates of antibody concentrations were comparable between patients and controls (p=0.70). In two-dose non-responders, a third SARS-CoV-2 vaccine elicited humoral responses in 19% (6/32) and CMI in 32% (10/31) participants. CONCLUSION: This study reveals comparable immunity decay rates between patients with anti-CD20 treatments and healthy volunteers, but inefficient humoral or CMI after a third SARS-CoV-2 vaccine in most two-dose humoral non-responders calling for individually tailored vaccination strategies in this population.Trial registration numberNCT04877496; ClinicalTrials.gov number.

Rational development and application of biomarkers in the field of autoimmunity: A conceptual framework guiding clinicians and researchers.

Clear guidance is needed in the development and implementation of laboratory biomarkers in medicine. So far, no standardized phased approach is established that would pilot researchers and clinicians in this process. This leads to often incompletely validated biomarkers, which can bear the consequence of wrong applications, misinterpretation and inadequate management in the clinical context. In this conceptual article, we describe a stepwise approach to develop and comprehensively validate laboratory biomarkers. We will delineate basic steps including technical performance, pre-analytical issues, and biological variation, as well as advanced aspects of biomarker utility comprising interpretability, diagnostic and prognostic accuracy, and health-care outcomes. These aspects will be illustrated by using well-known examples from the field of immunology. The application of this conceptual framework will guide researchers in conducting meaningful projects to develop and evaluate biomarkers for the use in clinical practice. Furthermore, clinicians will be able to adequately interpret pre-clinical and clinical diagnostic literature and rationally apply biomarkers in clinical practice. Improvement in the implementation and application of biomarkers might relevantly change the management and outcomes of our patients for the better.

Clinical Reasoning: A Dizzy Architect.

There is an increasing body of evidence describing an association between anti-Kelch-like protein 11 (KLHL11) encephalitis and various tumors such as seminoma. However, when the diagnosis of neoplasia is uncertain and the clinical syndrome resembles those caused by other etiologies, the possibility of anti-KLHL11 encephalitis may not be obvious during early clinical evaluations. We present the case of a 68-year-old man with clinical features of anti-KLHL11 encephalitis, in whom no clear signs of an active neoplasia could be found. However, a burnt-out germ cell tumor was suspected. This case highlights the importance of having a high clinical suspicion for anti-KLHL11 encephalitis in patients who exhibit symptoms and signs, even in the absence of an active tumor.

Humoral and cellular immune responses on SARS-CoV-2 vaccines in patients with anti-CD20 therapies: a systematic review and meta-analysis of 1342 patients.

BACKGROUND: Immune responses on SARS-CoV-2 vaccination in patients receiving anti-CD20 therapies are impaired but vary considerably. We conducted a systematic review and meta-analysis of the literature on SARS-CoV-2 vaccine induced humoral and cell-mediated immune response in patients previously treated with anti-CD20 antibodies. METHODS: We searched PubMed, Embase, Medrxiv and SSRN using variations of search terms 'anti-CD20', 'vaccine' and 'COVID' and included original studies up to 21 August 2021. We excluded studies with missing data on humoral or cell-mediated immune response, unspecified methodology of response testing, unspecified timeframes between vaccination and blood sampling or low number of participants (≤3). We excluded individual patients with prior COVID-19 or incomplete vaccine courses. Primary endpoints were humoral and cell-mediated immune response rates. Subgroup analyses included time since anti-CD20 therapy, B cell depletion and indication for anti-CD20 therapy. We used random-effects models of proportions. FINDINGS: Ninety studies were assessed. Inclusion criteria were met by 23 studies comprising 1342 patients. Overall rate of humoral response was 0.40 (95% CI 0.35 to 0.47). Overall rate of cell-mediated immune responses was 0.71 (95% CI 0.57 to 0.87). A time interval >6 months since last anti-CD20 therapy was associated with higher humoral response rates with 0.63 (95% CI 0.53 to 0.72) versus <6 months 0.2 (95% CI 0.03 to 0.43); p=0<01. Similarly, patients with circulating B cells more frequently showed humoral responses. Anti-CD20-treated kidney transplant recipients showed lower humoral response rates than patients with haematological malignancies or autoimmune disease. INTERPRETATION: Patients on anti-CD20 therapies can develop humoral and cell-mediated immune responses after SARS-CoV-2 vaccination, but subgroups such as kidney transplant recipients or those with very recent therapy and depleted B cell are at high risk for non-seroconversion and should be individually assessed for personalised SARS-CoV-2 vaccination strategies. Potential limitations are small patient numbers and heterogeneity of studies included. FUNDING: This study was funded by Bern University Hospital.

Spine Metastases in Immunocompromised Mice after Intracardiac Injection of MDA-MB-231-SCP2 Breast Cancer Cells.

Breast cancer cells frequently metastasize to bone, where their interaction with bone remodeling cell types enhances osteolytic bone destruction. Importantly, however, whereas skeletal analyses of xenograft models are usually restricted to hindlimb bones, human skeletal metastases are far more frequent in the spine, where trabecular bone mass is higher compared to femur or tibia. Here, we addressed whether breast cancer cells injected into immunocompromised mice metastasize to the spine and if this process is influenced by the amount of trabecular bone. We also took advantage of mice carrying the Col1a1-Krm2 transgene, which display severe osteoporosis. After crossing this transgene into the immunocompromised NSG background we injected MDA-MB-231-SCP2 breast cancer cells and analyzed their distribution three weeks thereafter. We identified more tumor cells and clusters of different size in spine sections than in femora, which allowed influences on bone remodeling cell types to be analyzed by comparing tumor-free to tumor-burdened areas. Unexpectedly, the Col1a1-Krm2 transgene did not affect spreading and metastatic outgrowth of MDA-MB-231-SCP2 cells, suggesting that bone tumor interactions are more relevant at later stages of metastatic progression.

Serological testing for SARS-CoV-2 antibodies in clinical practice: A comparative diagnostic accuracy study.

BACKGROUND: Serological tests are a powerful tool in the monitoring of infectious diseases and the detection of host immunity. However, manufacturers often provide diagnostic accuracy data generated through biased studies, and the performance in clinical practice is essentially unclear. OBJECTIVES: We aimed to determine the diagnostic accuracy of various serological testing strategies for (a) identification of patients with previous coronavirus disease-2019 (COVID-19) and (b) prediction of neutralizing antibodies against SARS-CoV-2 in real-life clinical settings. METHODS: We prospectively included 2573 consecutive health-care workers and 1085 inpatients with suspected or possible previous COVID-19 at a Swiss University Hospital. Various serological immunoassays based on different analytical techniques (enzyme-linked immunosorbent assays, ELISA; chemiluminescence immunoassay, CLIA; electrochemiluminescence immunoassay, ECLIA; and lateral flow immunoassay, LFI), epitopes of SARS-CoV-2 (nucleocapsid, N; receptor-binding domain, RBD; extended RBD, RBD+; S1 or S2 domain of the spike [S] protein, S1/S2), and antibody subtypes (IgG, pan-Ig) were conducted. A positive real-time PCR test from a nasopharyngeal swab was defined as previous COVID-19. Neutralization assays with live SARS-CoV-2 were performed in a subgroup of patients to assess neutralization activity (n = 201). RESULTS: The sensitivity to detect patients with previous COVID-19 was ≥85% in anti-N ECLIA (86.8%) and anti-S1 ELISA (86.2%). Sensitivity was 84.7% in anti-S1/S2 CLIA, 84.0% in anti-RBD+LFI, 81.0% in anti-N CLIA, 79.2% in anti-RBD ELISA, and 65.6% in anti-N ELISA. The specificity was 98.4% in anti-N ECLIA, 98.3% in anti-N CLIA, 98.2% in anti-S1 ELISA, 97.7% in anti-N ELISA, 97.6% in anti-S1/S2 CLIA, 97.2% in anti-RBD ELISA, and 96.1% in anti-RBD+LFI. The sensitivity to detect neutralizing antibodies was ≥85% in anti-S1 ELISA (92.7%), anti-N ECLIA (91.7%), anti-S1/S2 CLIA (90.3%), anti-RBD+LFI (87.9%), and anti-RBD ELISA (85.8%). Sensitivity was 84.1% in anti-N CLIA and 66.2% in anti-N ELISA. The specificity was ≥97% in anti-N CLIA (100%), anti-S1/S2 CLIA (97.7%), and anti-RBD+LFI (97.9%). Specificity was 95.9% in anti-RBD ELISA, 93.0% in anti-N ECLIA, 92% in anti-S1 ELISA, and 65.3% in anti-N ELISA. Diagnostic accuracy measures were consistent among subgroups. CONCLUSIONS: The diagnostic accuracy of serological tests for SARS-CoV-2 antibodies varied remarkably in clinical practice, and the sensitivity to identify patients with previous COVID-19 deviated substantially from the manufacturer's specifications. The data presented here should be considered when using such tests to estimate the infection burden within a specific population and determine the likelihood of protection against re-infection.

A novel functional mast cell assay for the detection of allergies.

BACKGROUND: Clinical management of allergic diseases has been hampered by the lack of safe and convenient tests to reliably identify culprit allergens and to closely follow changes in disease activity over time. Because allergy diagnosis is a complex and laborious multistep procedure, there is an urgent need for simpler but still functionally accurate ex vivo assays allowing objective diagnosis, substantiating treatment choices, and quantifying therapeutic responses. OBJECTIVE: In this study, we sought to develop a novel functional cell-based assay that relies on passive sensitization of allergic effector cells with patient serum, circumventing current limitations in allergy diagnosis. METHODS: We genetically engineered a conditional homeobox B8 (Hoxb8)-immortalized progenitor line from the bone marrow of mice that are transgenic for the human high-affinity IgE receptor (FcεRIα). These cells can be reproducibly differentiated into mature Hoxb8 mast cells within 5 days of culture in virtually unlimited numbers. RESULTS: We demonstrate that the established Hoxb8 mast cell assay can be used to accurately measure total IgE levels, identify culprit allergens, longitudinally monitor allergen-specific immunotherapy, and potentially determine the time point of tolerance induction upon allergen-specific immunotherapy in patients with allergy. To facilitate the analysis of large testing volumes, we demonstrate a proof-of-concept for a high-throughput screening application based on fluorescent cell barcoding using the engineered Hoxb8 mast cells. CONCLUSIONS: Our results indicate that this novel mast cell assay could represent a valuable tool to support clinicians in the identification of IgE-mediated allergies and in the quantification of treatment efficacy as well as duration of therapeutic response.

Symptoms, SARS-CoV-2 Antibodies, and Neutralization Capacity in a Cross Sectional-Population of German Children.

Background: Children and youth are affected rather mildly in the acute phase of COVID-19 and thus, SARS-CoV-2 infection infection may easily be overlooked. In the light of current discussions on the vaccinations of children it seems necessary to better identify children who are immune against SARS-CoV-2 due to a previous infection and to better understand COVID-19 related immune reactions in children. Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a) randomly, if they had an appointment for a regular health check-up or (b) if parents and children volunteered and actively wanted to participate in the study. Symptoms were recorded and two antibody tests were performed in parallel directed against S (in house test) and N (Roche Elecsys) viral proteins. In children with antibody response in either test, neutralization activity was determined. Results: We identified antibodies against SARS-CoV-2 in 162 of 2,832 eligible children (5.7%) between end of May and end of July 2020 in three, in part strongly affected regions of Bavaria in the first wave of the pandemic. Approximately 60% of antibody positive children (n = 97) showed high levels (>97th percentile) of antibodies against N-protein, and for the S-protein, similar results were found. Sufficient neutralizing activity was detected for only 135 antibody positive children (86%), irrespective of age and sex. Initial COVID-19 symptoms were unspecific in children except for the loss of smell and taste and unrelated to antibody responses or neutralization capacity. Approximately 30% of PCR positive children did not show seroconversion in our small subsample in which PCR tests were performed. Conclusions: Symptoms of SARS-CoV-2 infections are unspecific in children and antibody responses show a dichotomous structure with strong responses in many and no detectable antibodies in PCR positive children and missing neutralization activity in a relevant proportion of the young population.

Humoral and cellular responses to mRNA vaccines against SARS-CoV-2 in patients with a history of CD20 B-cell-depleting therapy (RituxiVac): an investigator-initiated, single-centre, open-label study.

BACKGROUND: B-cell-depleting therapies increase the risk of morbidity and mortality due to COVID-19. Evidence-based SARS-CoV-2 vaccination strategies for patients on B-cell-depleting therapies are scarce. We aimed to investigate humoral and cell-mediated immune responses to SARS-CoV-2 mRNA-based vaccines in patients receiving CD20-targeted B-cell-depleting agents for autoimmune disease, malignancy, or transplantation. METHODS: The RituxiVac study was an investigator-initiated, single-centre, open-label study done at the Bern University Hospital (Bern, Switzerland). Patients with a treatment history of anti-CD20-depleting agents (rituximab or ocrelizumab) and with no previous history of SARS-CoV-2 infection were enrolled between April 26 and June 30, 2021, for analysis of humoral and cell-mediated immune responses (by interferon-γ [IFNγ] release assay) at least 4 weeks after completing vaccination against SARS-CoV-2. Healthy controls without a history of SARS-CoV-2 infection were also enrolled at least 4 weeks after completing vaccination against SARS-CoV-2. All study participants received two doses of either the Pfizer-BioNTech BNT162b2 vaccine or the Moderna mRNA-1273 vaccine. The primary outcome was the proportion of patients with a history of anti-CD20 treatment who showed a humoral immune response against the SARS-CoV-2 spike protein in comparison with immunocompetent controls. Prespecified secondary endpoints were the effect of anti-CD20 therapy (including time since last treatment and cumulative dose) on humoral or cell-mediated immune responses to SARS-CoV-2 vaccination, and biomarkers of immunocompetence. This study is registered with ClinicalTrials.gov, NCT04877496. FINDINGS: The final study population comprised 96 patients and 29 immunocompetent controls. The median age of patients was 67 years (IQR 57-72) and of controls was 54 years (45-62), and 51 (53%) of 96 patients and 19 (66%) of 29 controls were female. The median time since last anti-CD20 treatment was 1·07 years (IQR 0·48-2·55) and the median cumulative dose of an anti-CD20 depleting agent was 2·80 g (1·50-5·00). Anti-spike IgG antibodies were detected in 47 (49%) of 96 patients 1·79 months (IQR 1·16-2·48) after the second vaccine dose compared to 29 (100%) of 29 controls 1·81 months (1·17-2·48) after the second vaccine dose (p<0·001). SARS-CoV-2-specific IFNγ release was detected in 13 (20%) of 66 patients and 21 (75%) of 28 of healthy controls (p<0·001). Only nine (14%) of 66 patients were double positive for anti-SARS-CoV-2 spike IgG and cell-mediated responses, compared with 21 (75%) of 28 healthy controls (p<0·001). Time since last anti-CD20 therapy (>7·6 months; positive predictive value 0·78), peripheral CD19+ cell count (>27 cells per µL; positive predictive value 0·70), and CD4+ lymphocyte count (>653 cells per µL; positive predictive value 0·71) were predictive of humoral vaccine response (area under the curve [AUC] 67% [95% CI 56-78] for time since last anti-CD20 therapy, 67% [55-80] for peripheral CD19+ count, and 66% [54-79] for CD4+ count). INTERPRETATION: This study provides further evidence of blunted humoral and cell-mediated immune responses elicited by SARS-CoV-2 mRNA vaccines in patients with a history of CD20 B-cell-depleting treatment. Lymphocyte subpopulation counts were associated with vaccine response in this highly vulnerable population. On validation, these results could help guide both the administration of SARS-CoV-2 vaccines and B-cell-depleting agents in this population. FUNDING: Bern University Hospital.

Cutaneous involvement in anti-HMGCR positive necrotizing myopathy.

OBJECTIVE: Anti-3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) positive immune-mediated necrotizing myopathy (IMNM) is a rare disease. It is induced by exogenous substances, most often by statins. Little is known about cutaneous manifestations of HMGCR positive IMNM and about HMGCR antibody positivity in other diseases. METHODS: The characteristics of patients with anti-HMGCR autoantibodies measured at our laboratory between January 2012 and September 2020 were studied. Characteristics of patients with IMNM were compared to those patients with positive antibodies but without muscle involvement. Associations of IMNM with other organ involvements were searched for. RESULTS: Of the 32 patients studied, 23 showed characteristics of IMNM, 9 did not fulfill current classification criteria but most showed signs of connective tissue diseases. Patients with IMNM were older (66 and 35 years, respectively; 0.92 (0.73-0.98); p < 0.001), had more frequent statin exposure (87% and 33%, respectively; 0.84 (0.61-0.94); p = 0.005) and higher mean peak CK (8717U/l and 329U/l, respectively; 1.0 (0.85-1.0); p < 0.001). 13/23 (56%) of IMNM patients showed cutaneous lesions; none of the patients suffered from cancer; only three IMNM patients showed drug-free complete remission. Incidence of IMNM in the catchment area of our center is at least 2.7/Mio/year. CONCLUSION: Cutaneous lesions were found to be more frequent in anti-HMRCR positive IMNM than previously reported. Titer of anti-HMGCR antibodies and CK levels were significantly higher in IMNM than in other autoimmune connective tissue diseases. The data support the hypothesis of an antigen-driven response in IMNM, and suggests an activation of autoreactive B-lymphocytes in non-IMNM patients.