Anti-citrullinated protein antibody detection by hemagglutination.

Objectives: ACPAs play an important role in the classification of RA and can be detected by serological tests. Several ACPA detection assays are available for clinical use, which are all based on ELISA(-like) tests with citrullinated peptides (CCP2) or alternative citrullinated proteins/peptides. We aimed to facilitate ACPA detection in low-volume laboratories and resource-poor environments by developing a rapid and easy-to-perform test.

Autoantibodies against a subunit of mitochondrial respiratory chain complex I in inclusion body myositis.

Background: Autoantibodies are found in up to 80 % of patients with idiopathic inflammatory myopathies (IIM) and are associated with distinct clinical phenotypes. Autoantibodies targeting cytosolic 5'-nucleotidase 1A (anti-NT5C1A) are currently the only known serum biomarker for the subgroup inclusion body myositis (IBM), although detected even in other autoimmune diseases. The aim of the study was to identify new autoimmune targets in IIM.

Circulating tRNA-derived fragments are decreased in patients with rheumatoid arthritis and increased in patients with psoriatic arthritis.

Introduction: tRNA-derived fragments (tRFs) play an important role in immune responses. To clarify the role of tRFs in autoimmunity we studied circulating tRF-levels in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA), and in a murine model for arthritis.

Material And Methods: Circulating tRF-levels were quantified by miR-Q RT-qPCR.

IL-6 and TNF are Potential Inflammatory Biomarkers in Facioscapulohumeral Muscular Dystrophy.

Background: FSHD is a highly prevalent inherited myopathy with a still poorly understood pathology.

Objective: To investigate whether proinflammatory cytokines are associated with FSHD and which specific innate immune cells are involved in its pathology.

Methods: First, we measured circulating cytokines in serum samples: IL-6 (FSHD, n = 150; HC, n = 98); TNF (FSHD, n = 150; HC, n = 59); IL-1α (FSHD, n = 150; HC, n = 66); IL-1β (FSHD, n = 150; HC, n = 98); MCP-1 (FSHD, n = 14; HC, n = 14); VEGF-A (FSHD, n = 14; HC, n = 14).

Citrulline is not a major determinant of autoantibody reactivity to neutrophil extracellular traps.

One of the main strategies of neutrophils in responding to microbial infections is the formation of neutrophil extracellular traps (NETs). NETs are web-like structures of decondensed chromatin associated with antimicrobial proteins. Citrullination plays an important role during NET formation and a substantial fraction of NET-associated proteins appeared to be citrullinated.

A Novel Method to Isolate RNase MRP Using RNA Streptavidin Aptamer Tags.

Interactions between RNA-binding proteins and RNA molecules are at the center of multiple biological processes. Therefore, accurate characterization of the composition of ribonucleoprotein complexes (RNPs) is crucial. Ribonuclease (RNase) for mitochondrial RNA processing (MRP) and RNase P are highly similar RNPs that play distinct roles at the cellular level; as a consequence, the specific isolation of either of these complexes is essential to study their biochemical function.

Mammalian Glycosylation Patterns Protect Citrullinated Chemokine MCP-1/CCL2 from Partial Degradation.

Monocyte chemoattractant protein-1 (MCP-1/CCL2) is a potent chemotactic agent for monocytes, primarily produced by macrophages and endothelial cells. Significantly elevated levels of MCP-1/CCL2 were found in synovial fluids of patients with rheumatoid arthritis (RA), compared to osteoarthritis or other arthritis patients. Several studies suggested an important role for MCP-1 in the massive inflammation at the damaged joint, in part due to its chemotactic and angiogenic effects.

Proteogenomic analysis of the autoreactive B cell repertoire in blood and tissues of patients with Sjögren's syndrome.

Objective: To comparatively analyse the aberrant affinity maturation of the antinuclear and rheumatoid factor (RF) B cell repertoires in blood and tissues of patients with Sjögren's syndrome (SjS) using an integrated omics workflow.

Methods: Peptide sequencing of anti-Ro60, anti-Ro52, anti-La and RF was combined with B cell repertoire analysis at the DNA, RNA and single cell level in blood B cell subsets, affected salivary gland and extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) of patients with SjS.

Results: Affected tissues contained anti-Ro60, anti-Ro52, anti-La and RF clones as a small part of a polyclonal infiltrate.

Surface Ig variable domain glycosylation affects autoantigen binding and acts as threshold for human autoreactive B cell activation.

The hallmark autoantibodies in rheumatoid arthritis are characterized by variable domain glycans (VDGs). Their abundant occurrence results from the selective introduction of N-linked glycosylation sites during somatic hypermutation, and their presence is predictive for disease development. However, the functional consequences of VDGs on autoreactive B cells remain elusive.

A novel experimental approach for the selective isolation and characterization of human RNase MRP.

RNase MRP is a ribonucleoprotein complex involved in the endoribonucleolytic cleavage of different RNAs. Mutations in the RNA component of the RNP are the cause of cartilage hair hypoplasia. Patients with cartilage hair hypoplasia are characterized by skeletal dysplasia.

Profiling Serum Antibodies Against Muscle Antigens in Facioscapulohumeral Muscular Dystrophy Finds No Disease-Specific Autoantibodies.

Background: FSHD is caused by specific genetic mutations resulting in activation of the Double Homeobox 4 gene (DUX4). DUX4 targets hundreds of downstream genes eventually leading to muscle atrophy, oxidative stress, abnormal myogenesis, and muscle inflammation. We hypothesized that DUX4-induced aberrant expression of genes triggers a sustained autoimmune response against skeletal muscle cells.

Anti-Cytosolic 5'-Nucleotidase 1A Autoantibodies Are Absent in Juvenile Dermatomyositis.

Objective: To assess anti-cytosolic 5'-nucleotidase 1A (anti-cN-1A) autoantibodies in children with juvenile dermatomyositis (DM) and healthy controls, using 3 different methods of antibody detection, as well as verification of the results in an independent cohort.

Methods: Anti-cN-1A reactivity was assessed in 34 Dutch juvenile DM patients and 20 healthy juvenile controls using the following methods: a commercially available full-length cN-1A enzyme-linked immunosorbent assay (ELISA), a synthetic peptide ELISA, and immunoblotting with a lysate from cN-1A-expressing HEK 293 cells. Sera from juvenile DM patients with active disease and those with disease in remission were analyzed.

BCG Vaccination Induces Long-Term Functional Reprogramming of Human Neutrophils.

The tuberculosis vaccine bacillus Calmette-Guérin (BCG) protects against some heterologous infections, probably via induction of non-specific innate immune memory in monocytes and natural killer (NK) cells, a process known as trained immunity. Recent studies have revealed that the induction of trained immunity is associated with a bias toward granulopoiesis in bone marrow hematopoietic progenitor cells, but it is unknown whether BCG vaccination also leads to functional reprogramming of mature neutrophils. Here, we show that BCG vaccination of healthy humans induces long-lasting changes in neutrophil phenotype, characterized by increased expression of activation markers and antimicrobial function.

Ultra-fast detection and quantification of nucleic acids by amplification-free fluorescence assay.

Two types of clinically important nucleic acid biomarkers, microRNA (miRNA) and circulating tumor DNA (ctDNA) were detected and quantified from human serum using an amplification-free fluorescence hybridization assay. Specifically, miRNAs hsa-miR-223-3p and hsa-miR-486-5p with relevance for rheumatoid arthritis and cancer related mutations BRAF and KRAS of ctDNA were directly measured. The required oligonucleotide probes for the assay were rationally designed and synthesized through a novel "clickable" approach which is time and cost-effective.

Low molecular weight silicones induce cell death in cultured cells.

Women with silicone gel-filled breast implants are exposed to organosilicon compounds, in particular methylsiloxanes, as a result of 'gel bleed' and implant rupture. Although these silicones were originally considered to be inert, increasing evidence indicates that they can cause serious health problems. Here, we have analyzed the effects of microdroplets of the methylcyclosiloxanes, in particular D4, on the viability of cultured human cells.

Mechanism of biomolecular recognition of trimethyllysine by the fluorinated aromatic cage of KDM5A PHD3 finger.

The understanding of biomolecular recognition of posttranslationally modified histone proteins is centrally important to the histone code hypothesis. Despite extensive binding and structural studies on the readout of histones, the molecular language by which posttranslational modifications on histone proteins are read remains poorly understood. Here we report physical-organic chemistry studies on the recognition of the positively charged trimethyllysine by the electron-rich aromatic cage containing PHD3 finger of KDM5A.

Autoantibodies to neutrophil extracellular traps represent a potential serological biomarker in rheumatoid arthritis.

Neutrophil extracellular traps (NETs) are networks of extracellular chromatin decorated with antimicrobial proteins, formed by neutrophils to entrap pathogens. NETs have been implicated in the generation of autoimmune reactions. Here, we investigate the reactivity of rheumatoid arthritis (RA) serum antibodies with NETs and explore whether anti-NET antibodies (ANETA) have a potential as biomarker in RA.

Global Characterization of Circulating Nucleic Acids.

Circulating nucleic acids (CNAs) include genomic and mitochondrial DNA fragments, small RNAs, and bacterial and viral DNA/RNA. Different mechanisms such as cell apoptosis, necrosis, and active CNA release from cells have been proposed to result in nucleic acids in the circulation. Application of next generation sequencing technology demonstrated that CNAs contain specific mutations, indels, microsatellite alterations, and epigenetic changes (DNA methylation) associated with various diseases.

Autoantibody testing in idiopathic inflammatory myopathies.

The diagnosis and classification of idiopathic inflammatory myopathies are based mainly on clinical and histological features. The discovery of myositis-specific and myositis-associated antibodies has simplified the (sub)classification of inflammatory myopathies. Patients suspected of having an idiopathic inflammatory myopathy should undergo routine antibody testing to gain more insight into distinct phenotypes, comorbidities, treatment response and prognosis.

Stimulus-dependent chromatin dynamics, citrullination, calcium signalling and ROS production during NET formation.

Neutrophils can release their chromatin to form neutrophil extracellular traps (NETs), a process known as NETosis. Although NET formation can be induced by various stimuli, recent evidence suggests that these stimuli do so via different mechanisms. Here, we have analysed NET formation induced by lipopolysaccharide (LPS), phorbol 12‑myristate 13‑acetate (PMA) and the calcium (Ca) ionophore A23187.

Sequential Prodrug Strategy To Target and Eliminate ACPA-Selective Autoreactive B Cells.

Autoreactive B cells are thought to play a pivotal role in many autoimmune diseases. Rheumatoid arthritis (RA) is an autoimmune disease affecting ∼1% of the Western population and is hallmarked by the presence of anticitrullinated proteins antibodies (ACPA) produced by autoreactive B cells. We intend to develop a method to target and selectively eliminate these autoreactive B cells using a sequential antigen prodrug targeting strategy.

Pathogenic variants in glutamyl-tRNA amidotransferase subunits cause a lethal mitochondrial cardiomyopathy disorder.

Mitochondrial protein synthesis requires charging mt-tRNAs with their cognate amino acids by mitochondrial aminoacyl-tRNA synthetases, with the exception of glutaminyl mt-tRNA (mt-tRNA). mt-tRNA is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. Defects involving the mitochondrial protein synthesis machinery cause a broad spectrum of disorders, with often fatal outcome.

Autoantibodies to Cytosolic 5'-Nucleotidase 1A in Primary Sjögren's Syndrome and Systemic Lupus Erythematosus.

Introduction: Autoantibodies to cytosolic 5'-nucleotidase 1A (cN-1A; NT5C1A) have a high specificity when differentiating sporadic inclusion body myositis from polymyositis and dermatomyositis. In primary Sjögren's syndrome (pSS) and systemic lupus erythematosus (SLE) anti-cN-1A autoantibodies can be detected as well. However, various frequencies of anti-cN-1A reactivity have been reported in SLE and pSS, which may at least in part be explained by the different assays used.

NETosis, complement, and coagulation: a triangular relationship.

NETosis is a regulated form of neutrophil cell death that contributes to the host defense against pathogens and was linked to various diseases soon after its first description in 2004. During NETosis, neutrophils release neutrophil extracellular traps (NETs), which can capture and kill bacteria and other pathogens to prevent them from spreading. Although substantial progress has been made in our understanding of NETosis, the precise mechanism underlying NETosis is still a matter of debate.

Sputum Anticitrullinated Protein Antibodies in Patients With Long-standing Rheumatoid Arthritis.

Objective: The aim of this study was to evaluate the presence of autoantibodies to cyclic citrullinated synthetic peptides (ACPAs) in the sputum of patients with long-standing rheumatoid arthritis (RA).

Methods: Nineteen consecutive RA patients and 16 age- and sex-matched control subjects participated in this cross-sectional study. All underwent complete lung function tests and provided induced sputum.