Identification of Clinically and Pathophysiologically Relevant Rheumatoid Factor Epitopes by Engineered IgG Targets

Objective: Rheumatoid factors (RFs), which are anti-IgG autoantibodies strongly associated with rheumatoid arthritis (RA), are also found in other diseases and in healthy individuals. RFs bind to various epitopes in the constant (Fc-) domain of IgG. Therefore, disease-specific reactivity patterns may exist. This study was undertaken in order to develop a new approach to dissecting RF epitope binding patterns across different diseases. Methods: We analyzed RF reactivity patterns in serum from patients with seropositive arthralgia, patients with RA, and patients with primary Sjögren’s syndrome (SS) using bioengineered, natively folded IgG-Fc targets that demonstrated selective RF binding toward several distinct regions of the IgG-Fc domain. Results: Rheumatoid factor responses primarily bound the Fc Elbow region, with a smaller number of RFs binding the Fc Tail region, while the Fc receptor binding region was hardly targeted. A restricted reactivity against the IgG-Fc Tail region was associated with less positivity for anti–citrullinated protein antibodies (ACPAs) and less arthritis development in arthralgia, whereas combined reactivity toward IgG-Fc Tail and Elbow regions was associated with more arthritis development. Reactivity toward the IgG-Fc Tail region was observed far more frequently in RA than in primary SS. Conclusion: Bioengineered IgG targets enable serologic characterization of RF reactivity patterns, and use of this approach appears to reveal patterns associated with ACPA detection and arthritis development in patients with arthralgia. These patterns are able to distinguish RA patients from primary SS patients. This new methodology improves the clinical value of RFs and our understanding of their pathophysiologic processes

Dynamics of circulating TNF during adalimumab treatment using a drug-tolerant TNF assay

Patients with rheumatoid arthritis (RA) can be successfully treated with tumor necrosis factor (TNF) inhibitors, including the monoclonal antibody adalimumab. Once in remission, a proportion of patients can successfully discontinue treatment, indicating that blocking TNF is no longer required for disease control. To explore the dynamics of circulating TNF during adalimumab treatment, we developed a competition enzyme-linked immunosorbent assay that can quantify TNF in the presence of large amounts of TNF inhibitor, i.e., a “drug-tolerant” assay. In 193 consecutive adalimumab-treated patients with RA, we demonstrated that circulating TNF increased in average of &gt;50-fold upon treatment and reached a stable concentration in time for most patients. A similar increase in TNF was found in 30 healthy volunteers after one dose of adalimumab. This implies that TNF in circulation during anti-TNF treatment is not primarily associated with disease activity. During treatment, TNF was in complex with adalimumab and could be recovered as inactive 3:1 adalimumab-TNF complexes. No quantitative association was found between TNF and adalimumab concentrations. Low TNF concentrations at week 4 were associated with a higher frequency of antidrug antibodies (ADAs) at subsequent time points, less frequent methotrexate use at baseline, and less frequent remission after 52 weeks. Also in healthy volunteers, early low TNF concentrations are associated with ADAs. In conclusion, longitudinal TNF concentrations are mostly stable during adalimumab treatment and may therefore not predict successful treatment discontinuation. However, early low TNF is strongly associated with ADA formation and may be used as timely predictor of nonresponse toward adalimumab treatment.</p

How to prepare stool banks for an appropriate response to the ongoing COVID-19 pandemic: Experiences in the Netherlands and a retrospective comparative cohort study for faecal microbiota transplantation

Background Faecal microbiota transplantation (FMT) is an efficacious treatment for patients with recurrent Clostridioides difficile infections (rCDI). Stool banks facilitate FMT by providing screened faecal suspensions from highly selected healthy donors. Due to the ongoing coronavirus disease 2019 (COVID-19) pandemic and the potential risk of SARS coronavirus-2 (SARS-CoV-2) transmission via FMT, many stool banks were forced to temporarily halt and adjust donor activities.Goal The evaluation of a strategy to effectively continue stool banking activities during the ongoing COVID-19 pandemic.Study To restart our stool banking activities after an initial halt, we implemented periodic SARS-CoV-2 screening in donor faeces and serum, and frequent donor assessment for COVID-19 related symptoms. FMT donor and recipient data obtained before (2016-2019) and during the COVID-19 pandemic (March 2020-August 2021) were compared to assess stool banking efficacy.Results Two out of ten donors developed COVID-19. No differences during versus before the COVID-19 pandemic were observed in the number of approved faeces donations (14 vs 22/month, p = 0.06), FMT requests for rCDI (3.9 vs 4.3/month, p = 0.6); rCDI patients eligible for FMT (80.6% vs 73.3%, p = 0.2); rCDI cure rate (90.3% vs 89.2%, p = 0.9); CDI-free survival (p = 0.7); the number of non-rCDI patients treated with FMT (0.5/month vs 0.4/month), and the number of possibly FMT related adverse events (9.5% vs 7.8%, p = 0.7). Two FMTs for rCDI were delayed due to COVID-19.Conclusions There is a continued need for FMT treatment of rCDI during the COVID-19 pandemic. Appropriate donor screening and SARS-CoV-2 infection prevention measures can be implemented in existing protocols without increasing the burden for donors, and allow safe, effective and efficient FMT during the ongoing COVID-19 pandemic. Stool banks should evaluate their SARS-CoV-2 donor screening protocols for long-term sustainability and efficacy, and share their experiences to help the utilisation, standardisation and improvement of stool banks worldwide.Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

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

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

CD5L is a canonical component of circulatory IgM

Immunoglobulin M (IgM) is an evolutionary conserved key component of humoral immunity, and the first antibody isotype to emerge during an immune response. IgM is a large (1 MDa), multimeric protein, for which both hexameric and pentameric structures have been described, the latter additionally containing a joining (J) chain. Using a combination of single-particle mass spectrometry and mass photometry, proteomics, and immunochemical assays, we here demonstrate that circulatory (serum) IgM exclusively exists as a complex of J-chain-containing pentamers covalently bound to the small (36 kDa) protein CD5 antigen-like (CD5L, also called apoptosis inhibitor of macrophage). In sharp contrast, secretory IgM in saliva and milk is principally devoid of CD5L. Unlike IgM itself, CD5L is not produced by B cells, implying that it associates with IgM in the extracellular space. We demonstrate that CD5L integration has functional implications, i.e., it diminishes IgM binding to two of its receptors, the FcαµR and the polymeric Immunoglobulin receptor. On the other hand, binding to FcµR as well as complement activation via C1q seem unaffected by CD5L integration. Taken together, we redefine the composition of circulatory IgM as a J-chain containing pentamer, always in complex with CD5L

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