Vibration based structural health monitoring of a composite plate with stiffeners

A vibration based damage identification algorithm is implemented to assess the damage of a thin-walled composite structure. The structure analysed is a skin with stiffeners, as frequently applied in aircraft components. Both experimental and numerical studies on a single composite skin--stiffener structure showed that the modal strain energy damage index (MSE--DI) algorithm is a suitable method for the detection and localization of a delamination of the stiffener from the skin. A recent study on a strip with a single stiffener and an artificial delamination is extended to a study on a plate with two stiffeners and an impact induced delamination damage

Cross-reactivity of IgM anti-modified protein antibodies in rheumatoid arthritis despite limited mutational load

Background Anti-modified protein antibodies (AMPA) targeting citrullinated, acetylated and/or carbamylated self-antigens are hallmarks of rheumatoid arthritis (RA). Although AMPA-IgG cross-reactivity to multiple post-translational modifications (PTMs) is evident, it is unknown whether the first responding B cells, expressing IgM, display similar characteristics or if cross-reactivity is crucially dependent on somatic hypermutation (SHM). We now studied the reactivity of (germline) AMPA-IgM to further understand the breach of B cell tolerance and to identify if cross-reactivity depends on extensive SHM. Moreover, we investigated whether AMPA-IgM can efficiently recruit immune effector mechanisms. Methods Polyclonal AMPA-IgM were isolated from RA patients and assessed for cross-reactivity towards PTM antigens. AMPA-IgM B cell receptor sequences were obtained by single cell isolation using antigen-specific tetramers. Subsequently, pentameric monoclonal AMPA-IgM, their germline counterparts and monomeric IgG variants were generated. The antibodies were analysed on a panel of PTM antigens and tested for complement activation. Results Pentameric monoclonal and polyclonal AMPA-IgM displayed cross-reactivity to multiple antigens and different PTMs. PTM antigen recognition was still present, although reduced, after reverting the IgM into germline. Valency of AMPA-IgM was crucial for antigen recognition as PTM-reactivity significantly decreased when AMPA-IgM were expressed as IgG. Furthermore, AMPA-IgM was 15- to 30-fold more potent in complement-activation compared to AMPA-IgG. Conclusions We provide first evidence that AMPA-IgM are cross-reactive towards different PTMs, indicating that PTM (cross-)reactivity is not confined to IgG and does not necessarily depend on extensive somatic hypermutation. Moreover, our data indicate that a diverse set of PTM antigens could be involved in the initial tolerance breach in RA and suggest that AMPA-IgM can induce complement-activation and thereby inflammation.Pathophysiology and treatment of rheumatic disease

Human transmission of blastocystis by fecal microbiota transplantation without development of gastrointestinal symptoms in recipients

Background. Patients with multiple recurrent Clostridioides difficile infections (rCDI) are treated with fecal microbiota transplantation (FMT), using feces provided by healthy donors. Blastocystis colonization of donors is considered an exclusion criterion, whereas its pathogenicity is still under debate. Methods. The introduction of molecular screening for Blastocystis sp. at our stool bank identified 2 donors with prior negative microscopies but positive polymerase chain reactions (PCRs). Potential transmission of Blastocystis sp. to patients was assessed on 16 fecal patient samples, pre- and post-FMT, by PCR and subtype (ST) analyses. In addition, clinical outcomes for the treatment of rCDI (n = 31), as well as the development of gastrointestinal symptoms, were assessed. Results. There was 1 donor who carried Blastocystis ST1, and the other contained ST3. All patients tested negative for Blastocystis prior to FMT. With a median diagnosis at 20.5 days after FMT, 8 of 16 (50%) patients developed intestinal colonization with Blastocystis, with identical ST sequences as their respective donors. Blastocystis-containing fecal suspensions were used to treat 31 rCDI patients, with an FMT success rate of 84%. This success rate was not statistically different from patients transferred with Blastocystis sp.–negative donor feces (93%, 76/82). Patients transferred with Blastocystis sp.–positive donor feces did not report any significant differences in bowel complaints in the first week, after 3 weeks, or

A standardised model for stool banking for faecal microbiota transplantation : a consensus report from a multidisciplinary UEG working group

Background Faecal microbiota transplantation is an emerging therapeutic option, particularly for the treatment of recurrent Clostridioides difficile infection. Stool banks that organise recruitment and screening of faeces donors are being embedded within the regulatory frameworks described in the European Union Tissue and Cells Directive and the technical guide to the quality and safety of tissue and cells for human application, published by the European Council. Objective Several European and international consensus statements concerning faecal microbiota transplantation have been issued. While these documents provide overall guidance, we aim to provide a detailed description of all processes that relate to the collection, handling and clinical application of human donor stool in this document. Methods Collaborative subgroups of experts on stool banking drafted concepts for all domains pertaining to stool banking. During a working group meeting in the United European Gastroenterology Week 2019 in Barcelona, these concepts were discussed and finalised to be included in our overall guidance document about faecal microbiota transplantation. Results A guidance document for all domains pertaining to stool banking was created. This document includes standard operating manuals for several processes involved with stool banking, such as handling of donor material, storage and donor screening. Conclusion The implementation of faecal microbiota transplantation by stool banks in concordance with our guidance document will enable quality assurance and guarantee the availability of donor faeces preparations for patients.Peer reviewe

A standardised model for stool banking for faecal microbiota transplantation: a consensus report from a multidisciplinary UEG working group

Background Faecal microbiota transplantation is an emerging therapeutic option, particularly for the treatment of recurrent Clostridioides difficile infection. Stool banks that organise recruitment and screening of faeces donors are being embedded within the regulatory frameworks described in the European Union Tissue and Cells Directive and the technical guide to the quality and safety of tissue and cells for human application, published by the European Council.Objective Several European and international consensus statements concerning faecal microbiota transplantation have been issued. While these documents provide overall guidance, we aim to provide a detailed description of all processes that relate to the collection, handling and clinical application of human donor stool in this document.Methods Collaborative subgroups of experts on stool banking drafted concepts for all domains pertaining to stool banking. During a working group meeting in the United European Gastroenterology Week 2019 in Barcelona, these concepts were discussed and finalised to be included in our overall guidance document about faecal microbiota transplantation.Results A guidance document for all domains pertaining to stool banking was created. This document includes standard operating manuals for several processes involved with stool banking, such as handling of donor material, storage and donor screening.Conclusion The implementation of faecal microbiota transplantation by stool banks in concordance with our guidance document will enable quality assurance and guarantee the availability of donor faeces preparations for patients.Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

Novel approach to monitor intravenous immunoglobulin pharmacokinetics in humans using polymorphic determinants in IgG1 constant domains

Clinical efficacy of intravenous immunoglobulin treatment (IVIg) is related to its pharmacokinetic (PK) profile. Its usual evaluation, by measuring serum total IgG levels, is imprecise, because IVIg cannot be distinguished from endogenous IgG. We developed ELISAs to specifically monitor the PK of IVIg using the polymorphic determinants G1m(a), G1m(x), and G1m(f). The specificity of the IgG1 allotype assays was sufficient to determine IVIg concentrations as low as 0.1 mg/mL in sera from individuals not expressing the respective markers. IVIg was quantified in posttreatment serum from patients with Guillain–Barré syndrome (GBS) by measuring IgG1 allotypes not expressed endogenously. After serotyping, 27/28 GBS patients were found eligible for IVIg monitoring using one or two genetic markers. In 17 cases, IVIg levels could be determined by both anti-G1m(a) and anti-G1m(x) measurement, showing significant correlation. Longitudinal monitoring of IVIg PK in seven GBS patients showed potential differences in clearance of total IgG versus IVIg-derived IgG, highlighting that total IgG measurements may not accurately reflect IVIg PK. To summarize, anti-IgG1 allotype assays can discriminate between endogenous IgG and therapeutic polyclonal IgG. These assays will be an important tool to better understand the variability in IVIg PK and treatment response of all patients treated with IVIg. © 2021 Wiley-VCH GmbH

At Critically Low Antigen Densities, IgM Hexamers Outcompete Both IgM Pentamers and IgG1 for Human Complement Deposition and Complement-Dependent Cytotoxicity

IgM is secreted as a pentameric polymer containing a peptide called the joining chain (J chain). However, integration of the J chain is not required for IgM assembly and in its absence IgM predominantly forms hexamers. The conformations of pentameric and hexameric IgM are remarkably similar with a hexagonal arrangement in solution. Despite these similarities, hexameric IgM has been reported to be a more potent complement activator than pentameric IgM, but reported relative potencies vary across different studies. Because of these discrepancies, we systematically investigated human IgM-mediated complement activation. We recombinantly generated pentameric and hexameric human IgM (IgM+J and IgM-J, respectively) mAbs and measured their ability to induce complement deposition and complement-dependent cytotoxicity when bound to several Ags at varying densities. At high Ag densities, hexameric and pentameric IgM activate complement to a similar extent as IgG1. However, at low densities, hexameric IgM outcompeted pentameric IgM and even more so IgG1. These differences became progressively more pronounced as antigenic density became critically low. Our findings highlight that the differential potency of hexameric and pentameric IgM for complement activation is profoundly dependent on the nature of its interactions with Ag. Furthermore, it underscores the importance of IgM in immunity because it is a more potent complement activator than IgG1 at low Ag densities.Pathophysiology and treatment of rheumatic disease

Elevated Fab glycosylation of anti-hinge antibodies

Objective: Rheumatoid arthritis (RA) is characterized by systemic inflammation and the presence of anti-citrullinated protein antibodies (ACPAs), which contain remarkably high levels of Fab glycosylation. Anti-hinge antibodies (AHAs) recognize immunoglobulin G (IgG) hinge neoepitopes exposed following cleavage by inflammation-associated proteases, and are also frequently observed in RA, and at higher levels compared to healthy controls (HCs). Here, we investigated AHA specificity and levels of Fab glycosylation as potential immunological markers for RA. Method: AHA serum levels, specificity, and Fab glycosylation were determined for the IgG1/4-hinge cleaved by matrix metalloproteinase-3, cathepsin G, pepsin, or IdeS, using enzyme-linked immunosorbent assay and lectin affinity chromatography, in patients with early active RA (n = 69) and HCs (n = 97). Results: AHA reactivity was detected for all hinge neoepitopes in both RA patients and HCs. Reactivity against CatG-IgG1-F(ab´)2s and pepsin-IgG4-F(ab´)2s was more prevalent in RA. Moreover, all AHA responses showed increased Fab glycosylation levels in both RA patients and HCs. Conclusions: AHA responses are characterized by elevated levels of Fab glycosylation and highly specific neoepitope recognition, not just in RA patients but also in HCs. These results suggest that extensive Fab glycosylation may develop in response to an inflammatory proteolytic microenvironment, but is not restricted to RA

Update of treatment algorithms for Clostridium difficile infection

Clostridium difficile is the leading cause of antibiotic-associated diarrhea, both in healthcare facilities and the community. The recurrence rate of C. difficile infection (CDI) remains high, up to 20%. Since the publication of the ESCMID guidance document on CDI treatment in 2014, new therapeutic approaches have been developed and tested to achieve higher sustained clinical cure in CDI. To review novel treatments and approaches for CDI, except probiotics and vaccines. We focused on new antibiotics, antibiotic inactivators, monoclonal antibodies (mAbs), and gut microbiota modulating therapies. A literature review was performed for clinical trials published in Pubmed, Embase, or Cochrane library between January 2013 and November 2017. We analyzed 28 clinical trials and identified 14 novel agents. Completed phase II studies were found for cadazolid, LFF571, ridinilazole, and non-toxigenic C. difficile strains. Four phase III active comparator studies comparing vancomycin with bezlotoxumab, surotomycin (n=2), and rifaximin have been published. Seven clinical trials for treatment of multiple recurrent CDI with fecal microbiota transplantation (FMT) were analyzed, describing FMT by upper or lower gastrointestinal route (n=5) or by capsules (n=2). Metronidazole is mentioned in the ESCMID guideline as first line therapy, but we propose that vancomycin orally will become the first choice when antibiotic treatment for CDI is necessary and the severity of the disease difficult to assess. Fidaxomicin is an good alternative, especially in patients at risk to develop a relapse. Vancomycin combined with FMT remains the primary therapy for multiple recurrent CDI . We anticipate that new medication that protects the gut microbiota will be further developed and tested to prevent CDI during antibiotic therap