Immune Complex Formation Research Articles

Unique Interplay Between Antinuclear Antibodies and Nuclear Molecules in the Pathogenesis of Systemic Lupus Erythematosus.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease that primarily affects young women and causes a wide range of inflammatory manifestations. The hallmark of SLE is the production of antibodies to components of the cell nucleus (antinuclear antibodies [ANAs]). These antibodies can bind to DNA, RNA, and protein complexes with nucleic acids. Among ANAs, antibodies to DNA (anti-DNA) are markers for classification and disease activity, waxing and waning disease activity in many patients. In the blood, anti-DNA antibodies can bind to DNA to form immune complexes with two distinct roles in pathogenesis: (1) renal deposition to provoke nephritis and (2) stimulation of cytokine production following uptake into innate immune cells and interaction with internal nucleic acid sensors. These sensors are part of an internal host defense system in the cell cytoplasm that can respond to DNA from infecting organisms; during cell stress, DNA from nuclear and mitochondrial sources can also trigger these sensors. The formation of immune complexes requires a source of extracellular DNA in an immunologically accessible form. As shown in in vivo and in vitro systems, extracellular DNA can emerge from dead and dying cells in both a free and a particulate form. Neutrophils undergoing the process of NETosis can release DNA in mesh-like structures called neutrophil extracellular traps. In SLE, therefore, the combination of ANAs and immunologically active DNA can create new structures that can promote inflammation throughout the body as well as drive organ inflammation and damage.

Mitochondrial Dysfunction in Systemic Lupus Erythematosus with a Focus on Lupus Nephritis.

Systemic lupus erythematosus (SLE) is an autoimmune disease affecting mostly women of child-bearing age. Immune dysfunction in SLE results from disrupted apoptosis which lead to an unregulated interferon (IFN) stimulation and the production of autoantibodies, leading to immune complex formation, complement activation, and organ damage. Lupus nephritis (LN) is a common and severe complication of SLE, impacting approximately 30% to 40% of SLE patients. Recent studies have demonstrated an alteration in mitochondrial homeostasis in SLE patients. Mitochondrial dysfunction contributes significantly to SLE pathogenesis by enhancing type 1 IFN production through various pathways involving neutrophils, platelets, and T cells. Defective mitophagy, the process of clearing damaged mitochondria, exacerbates this cycle, leading to increased immune dysregulation. In this review, we aim to detail the physiopathological link between mitochondrial dysfunction and disease activity in SLE. Additionally, we will explore the potential role of mitochondria as biomarkers and therapeutic targets in SLE, with a specific focus on LN. In LN, mitochondrial abnormalities are observed in renal cells, correlating with disease progression and renal fibrosis. Studies exploring cell-free mitochondrial DNA as a biomarker in SLE and LN have shown promising but preliminary results, necessitating further validation and standardization. Therapeutically targeting mitochondrial dysfunction in SLE, using drugs like metformin or mTOR inhibitors, shows potential in modulating immune responses and improving clinical outcomes. The interplay between mitochondria, immune dysregulation, and renal involvement in SLE and LN underscores the need for comprehensive research and innovative therapeutic strategies. Understanding mitochondrial dynamics and their impact on immune responses offers promising avenues for developing personalized treatments and non-invasive biomarkers, ultimately improving outcomes for LN patients.

Reduction of oxidative stress response and protection of liver and renal cell functions by reduced glutathione in lower limb arterial ischemia–reperfusion in New Zealand white rabbits with high triglyceride levels

ObjectiveAcute liver and kidney injury is the most common complication after aortic surgery, which seriously affects the survival and safety of perioperative patients. The presence of chronic preoperative liver and renal insufficiency, presence of preoperative blood inflammation indicators, duration of intraoperative extracorporeal circulation, and volume of red blood cell transfusion are the main influencing factors for acute postoperative liver and kidney injuries. In recent years, with the research progress on oxidative stress, a growing body of evidence has demonstrated that oxidative stress may cause tissue damage after ischemia–reperfusion (IR). However, the impact of the oxidative stress of distal tissues caused by IR on liver and renal cells after arterial surgeries has not yet been elucidated. MethodsNew Zealand white rabbits were used for the experiments and were divided into three groups. Among them, two groups were fed high-fat feed to establish a white rabbit model of hypertriglyceridemia, whereas the control group was provided with ordinary feed. In the experiment, white rabbits were subjected to occlusion of the infrarenal aorta abdominalis to simulate IR of the lower limbs. The effects of high triglyceride levels after the arterial IR of the lower limbs were investigated using the contents of reactive oxygen species (ROS) and malondialdehyde (MDA), a fat metabolite, in ischemic muscle tissues and blood tissues. One of the groups receiving high-fat feed received intervention with reduced glutathione (GSH) before IR of the lower limbs. Pathological studies were performed to identify the expression levels of inflammatory factors and inflammatory cells in liver and renal cells as well as cell apoptosis. The effects of GSH administration before IR on reducing the oxidative stress in adipose tissues and alleviating liver and kidney damage after stress response were investigated. ResultsAfter IR, the increases in ROS and MDA in ischemic muscle tissues and blood tissues were higher in white rabbits with high triglyceride levels than in those that only received ordinary feed or received intervention with GSH. In addition, for white rabbits with high triglyceride levels, the TNF-α expression levels in the liver increased after IR. Moreover, a considerable increase in the expression of TNF-α, IL-6, macrophages, and T lymphocytes were observed in renal cells. A large number of inflammatory cells and the formation of immune complexes were also noted in the glomeruli; in addition, cell apoptosis was promoted. ConclusionThis study showed that high triglyceride levels enhanced the oxidative stress response and increased ROS production in New Zealand white rabbits after arterial IR of the lower limbs. High ROS levels activated the expression of inflammatory factors and inflammatory cells in the liver and kidney, which affected cell functions and promoted apoptosis. At high triglyceride levels, GSH downregulated ROS production in oxidative stress after IR, thereby protecting liver and kidney functions.

IgA vasculitis with nephritis: an overview of the pathogenesis and clinical characteristic.

IgA vasculitis with nephritis (IgAVN) is closely related to IgA nephritis (IgAN) and IgA vasculitis (IgAV), but the clinical characteristics and exact pathogenesis of IgAVN remain unclear. In the present study, we have reviewed 8 clinical trials with different treatments and found that most IgAVN patients had partial recovery after treatments while few patients (26.5%) recovered completely within 6 months. Adding cyclophosphamide to mycophenolate mofetil was beneficial in children with severe kidney damage but was not effective in adults with serious organ damage (p=0.847). Tonsillectomy reduced the recurrence rate (p=0.03). In 18 reported cases we summarised, intravenous methylprednisolone pulse (MEP) combined with immunosuppressants (66.7%) and MEP combined with oral prednisolone (27.8%) were the two most commonly utilised treatments, and rituximab (40%) was the most frequently used monoclonal antibody. Mechanistically, activated cytotoxic T lymphocytes, natural killer cells, macrophage and completements contributed to the inflammation and endothelial cell apoptosis in IgAVN patients. Galactose-deficient IgA1 may be a threshold for IgAVN. The bulk formation of immune complexes and the decreased clearance rate led to the deposition of immune complexes. In severe cases, coagulation cascade would be triggered and thus caused renal fibrosis.

#2314 Circulating immune complexes concentration and complement activation in sensitized kidney transplant recipients

Abstract Background and Aims Chronic antibody mediated rejection of the kidney transplant is the most common cause of graft loss in the late posttransplant period. Crucial in this process seems to be the role of classical pathway complement activation due to the formation of immune complexes. The formation of immune complexes is a benign process of a normally functioning immune system. In kidney transplant recipients (KTRs), the production of donor specific IgG/IgM antibodies (DSAs) against donor antigens (MHC molecules, ABO blood group antigens) leads to the attachment of immune complexes to cell membranes and subsequent tissue damage through complement activation. The attachment of C1q complement fragment to the immune complexes holds an important part in this process. This study aims to determine the levels of immune complexes as well as classical pathway complement activation in sensitized kidney transplant recipients. Method In this cross-sectional study 3 groups of KTRs were compared as to the levels of immunocomplexes concentration and classical pathway complement activation. Fourteen KTRs with preformed or de novo donor specific antibodies were compared to 28 kidney transplant recipients with no DSAs and to 22 subjects with no history of chronic kidney disease (controls). We used MicroVue Complement CIC-C1q EIA that is designed to detect immunocomplexes that bind to C1q in human serum or plasma. In order to estimate total classical pathway complement activation in serum, we used MicroVue Complement CH50 Eq EIA. Results Kidney function (eGFR) of KTRs with and without DSAs was similar (53.1 ± vs. 60.8 ± ml/min/1.73 m2, p = 0.54) but lower in comparison to controls (106.4 ml/min/1.73 m2, p < 0.001). We found a significantly higher concentration of C1q-immunocomplexes in the serum of KTRs with donor specific antibodies, in comparison to controls, as well as to the group of kidney transplant recipients with no DSAs (6.78 ± 2.7 vs. 4.83 ± 1.9 vs. 5.04 ± 1.2 μgEq/ml respectively, p = 0.0078). Furthermore, there was no significant difference of C1q-immunocomplexes between kidney transplant recipients with no DSAs and controls. Finally, a significant reduction of CH50 levels was observed in KTRs with DSAs as compared to controls and KTRs with no DSAs (39.2 ± 14.9 vs. 70.6 ± 34.3 vs. 67.9 ± 39.9 U/ml respectively, p = 0.003), which suggests higher levels of classical pathway complement activation. CH50 levels in KTRs with DSAs, who were further subcategorized in those with preformed and those with de novo DSAs were similar (39.68 ± 15.6 vs 39.08 ± 16.04 U/ml). Conclusion Kidney transplant recipients with donor specific antibodies have increased serum levels of immune complexes and increased classical pathway complement activation.

#1360 SARS-COV-2 protein in renal tissue enhanced activation of complement system in MN patients with COVID-19 infection

Abstract Background and Aims Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults. Complement plays an important role in the pathogenesis of MN. COVID-19 infection has been reported to be associated with the occurrence and recurrence of MN. Only few kidney biopsies from COVID-19 patients demonstrate the presence of SARS-CoV-2 in the tissue. The clinical and pathological characteristics and complement system activation of patients with SARS-COV2 in renal tissue are unclear, needing to further study. Method From December 2022 to June 2023, patients with renal biopsy-proven MN at Beijing Anzhen hospital who had experienced COVID-19 infection before proteinuria onset and renal biopsy were enrolled. One hundred patients with primary MN diagnosed from December 2018 to June 2019 (with no COVID-19) were enrolled as control. Patient medical records were reviewed for clinical and pathological data. We performed immunofluorescence and in situ hybridization assays for detection of the SARS-COV2. Glomerular staining for factor H, FHR-5 and MAC were detected by immunohistochemical. Serum C5b-9 were detected by enzyme-linked immunosorbent assay. Clinicopathological and immunological features between MN patients with and without SARS-COV2 infection were analyzed. Results A total of 38 MN patients was proteinuria onset after COVID-19 infection, including 11 patients had SARS-COV protein positive staining along capillary loops in glomerular deposits or in cytoplasm of tubular epithelial cells. The immunofluorescence result shows strong colocalization of SARS-COV2 and IgG, which suggests that SARS-COV protein participated in the formation of immune complex. Compared with primary MN patients, the serum albumin level of 38 MN patients with COVID-19 infection were lower (p = 0.011). However, the clinical manifestations of 11 MN patients with SARS-COV2 renal positive staining were obviously serous. Compared with primary MN patients, urinary protein and serum creatine levels significantly increased (p = 0.027 and p = 0.005), while serum albumin levels decreased (p = 0.014) and the proportion of nephrotic syndrome (p = 0.037) was higher. There was no significant difference in pathological manifestations between MN patients with or without COVID-19 infection. In follow-up, the proportion of patients with urinary protein decreased greater than 50% in MN patients with COVID-19 infection was lower than that in primary MN patients. of urinary protein level Serum level of complement C3 (p = 0.007) and MAC (P = 0.001) in MN patients with COVID-19 infection was significantly higher than that of primary MN patients, especially MN patients with renal tissue positive staining of SARS-COV2 protein (p = 0.002 and p = 0.007). In 38 MN patients with COVID-19 infection, compared with patients with renal tissue negative for SARS-COV2 protein, patients with renal tissue positive for SARS-COV2 protein presented with stronger intensity of MAC deposition (p = 0.023) and factor H deposition (p = 0.002). Conclusion The clinical manifestation of MN patients who was onset after COVID-19 infection with renal tissue positive for SARS-COV2 protein were not only significantly worse than those of primary MN patients, but also worse than patients without tissue SARS-COV2 positive MN patients. We speculate that the reason is the enhanced activation of the complement system in renal tissue.

#2086 Understanding B cell memory autoreactivity in idiopathic membranous nephropathy for tailored therapy

Abstract Background and Aims Idiopathic membranous nephropathy (iMN) is an autoantibody-mediated glomerular disease, and one of the leading causes of nephrotic syndrome in adults. iMN is caused by the formation of immune complexes composed by IgG autoantibodies and target antigens expressed on podocytes. The main autoantigen is the phospholipase A2 receptor1 (PLA2R1) and the antibodies are mainly belonging to the IgG4 isotype. Those immune complexes are responsible for profound changes in the structure and function of the podocytes and disruption of the glomerular barrier. Nevertheless, despite complement components at the site of glomerular injury have been found in biopsies from patients with MN, many factors involved in the pathogenesis are still unclear. We overall aim at characterizing both the serological and the memory cellular component in iMN patients, with identification of dominant B cell epitopes recognized by circulating autoantibodies and autoreactive memory B cells, which could be potentially used to deplete PLA2R1 specific memory B cells and plasma blasts. Method We analyzed the serum from a cohort of 159 iMN patients collected at diagnosis without any previous or concomitant treatment as well as a similar number of healthy controls’ samples. An ELISA-based quantification method has been used to estimate the concentration of circulating anti-PLA2R1 antibodies. Furthermore, we processed 27 additional blood samples from independent iMN patients as well as age and gender matched healthy controls to extract and analyze peripheral blood mononuclear cells by flow cytometry (BD FACS Fortessa) and identify the major B and T cell populations via multi-color staining. In order to identify and clone human anti-PLA2R1 antibodies from primary memory B cells we reproduced the experimental workflow exactly as described in Lindner J.M. et al. Immunity 2019. The isolated antibodies were then characterized with analytical methods (affinity, binding, epitope determination and complement activation ability) and used in competition assays. Results A deep analysis of the serum reactivity has been performed and iMN patients showed a high prevalence of autoantibodies against PLA2R1, mostly of high affine IgG4 subclass with a broad concentration range (1-20ug/ml). A concomitant IgG1 response versus PLA2R1 has been also detected in the serum in different proportion with IgG4. An extended immunophenotyping of circulating peripheral blood mononuclear cells revealed an altered B and T cell compartment in iMN patients. In particular, we described an expansion of circulating CD27neg IgG4 memory B cells, IgG4 plasma blasts, CD4+ T follicular helper cells and CX3CR1+ T peripheral helper cells. Moreover, we isolated and cloned five very specific, highly affine, and somatically hypermutated patient's derived anti-PLA2R1 antibodies. Competition experiments between patient sera and patients’ derived monoclonal antibodies showed a strong inhibitory effect, indicating the presence of a shared epitope recognized on the surface of the CysR domain of PLA2R1. The identified epitope has also shown an important role in complement activation, despite a component patient-specific seems to be involved as well. Conclusion Overall, we performed a comprehensive characterization of the autoreactive B cell memory compartment in iMN, shedding lights on the complexity of the autoantibody repertoire. Indeed, the investigation of the granularity of the anti-PLA2R1 response in term of IgG1 versus IgG4 isotypes provided a potential new way to stratify the patients’ population and potentially tailored the therapy or follow the disease progression. Moreover, the isolation of patient's derived anti-PLA2R1 antibodies opened the possibility of using them the as tools to establish new models directly from the in vivo-selected specificities. Finally, the identification of an immunodominant epitope within PLA2R1 shared among the patients is crucial to develop molecules aimed at depletion of PLA2R1 specific memory B cells and plasma blasts in the patients.

Recombinant ADAMTS13 for Immune Thrombotic Thrombocytopenic Purpura

SummaryIn patients with immune thrombotic thrombocytopenic purpura (iTTP), autoantibodies against the metalloprotease ADAMTS13 lead to catastrophic microvascular thrombosis. However, the potential benefits of recombinant human ADAMTS13 (rADAMTS13) in patients with iTTP remain unknown. Here, we report the clinical use of rADAMTS13, which resulted in the rapid suppression of disease activity and complete recovery in a critically ill patient whose condition had proved to be refractory to all available treatments. We also show that rADAMTS13 causes immune complex formation, which saturates the autoantibody and may promote its clearance. Our data support the role of rADAMTS13 as a novel adjunctive therapy in patients with iTTP.

Vaccines and the Eye: Current Understanding of the Molecular and Immunological Effects of Vaccination on the Eye.

Vaccination is a public health cornerstone that protects against numerous infectious diseases. Despite its benefits, immunization implications on ocular health warrant thorough investigation, particularly in the context of vaccine-induced ocular inflammation. This review aimed to elucidate the complex interplay between vaccination and the eye, focusing on the molecular and immunological pathways implicated in vaccine-associated ocular adverse effects. Through an in-depth analysis of recent advancements and the existing literature, we explored various mechanisms of vaccine-induced ocular inflammation, such as direct infection by live attenuated vaccines, immune complex formation, adjuvant-induced autoimmunity, molecular mimicry, hypersensitivity reactions, PEG-induced allergic reactions, Type 1 IFN activation, free extracellular RNA, and specific components. We further examined the specific ocular conditions associated with vaccination, such as uveitis, optic neuritis, and retinitis, and discussed the potential impact of novel vaccines, including those against SARS-CoV-2. This review sheds light on the intricate relationships between vaccination, the immune system, and ocular tissues, offering insights into informed discussions and future research directions aimed at optimizing vaccine safety and ophthalmological care. Our analysis underscores the importance of vigilance and further research to understand and mitigate the ocular side effects of vaccines, thereby ensuring the continued success of vaccination programs, while preserving ocular health.

Structural properties of immune complexes formed by viral antigens and specific antibodies shape the inflammatory response of macrophages

Data on the course of viral infections revealed severe inflammation as a consequence of antiviral immune response. Despite extensive research, there are insufficient data on the role of innate immune cells in promoting inflammation mediated by immune complexes (IC) of viral antigens and their specific antibodies. Recently, we demonstrated that antigens of human polyomaviruses (PyVs) induce an inflammatory response in macrophages. Here, we investigated macrophage activation by IC. We used primary murine macrophages as a cell model, virus-like particles (VLPs) of PyV capsid protein as antigens, and a collection of murine monoclonal antibodies (mAbs) of IgG1, IgG2a, IgG2b subclasses. The inflammatory response was investigated by analysing inflammatory chemokines and activation of NLRP3 inflammasome. We observed a diverse pattern of chemokine secretion in macrophages treated with different IC compared to VLPs alone. To link IC properties with cell activation status, we characterised the IC by advanced optical and acoustic techniques. Ellipsometry provided precise real-time kinetics of mAb-antigen interactions, while quartz crystal microbalance measurements showed changes in conformation and viscoelastic properties during IC formation. These results revealed differences in mAb-antigen interaction and mAb binding parameters of the investigated IC. We found that IC-mediated cell activation depends more on IC characteristics, including mAb affinity, than on mAb affinity for the activating Fc receptor. IC formed by the highest affinity mAb showed a significant enhancement of inflammasome activation. This may explain the hyperinflammation related to viral infection and vaccination. Our findings demonstrate that IC promote the viral antigen-induced inflammatory response depending on antibody properties.

Burden, Outcome, and Comorbidities of Extrahepatic Manifestations in Hepatitis B Virus Infections.

Hepatitis B virus (HBV) infections affect approximately 296 million people around the world, and the prevalence of any past or present HBV infection during the years 2015-2018 was as high as 4.3%. Acute HBV infection often presents with nonspecific symptoms and is usually self-limited, but 5% of patients can have persistent infections leading to chronic HBV infection and the risk of turning into chronic HBV infection is significantly higher in babies with vertical transmission (95%). Patients with chronic HBV infection are usually asymptomatic, but 15 to 40% of chronic HBV carriers develop cirrhosis and/or hepatocellular carcinoma. In addition to liver-related disorders, HBV is also associated with several extrahepatic complications, including glomerulonephritis, cryoglobulinemia, neurologic disorders, psychological manifestations, polyarthritis, and dermatologic disorders. Making the diagnosis of HBV can be challenging since patients with chronic infections can remain symptom-free for decades before developing cirrhosis or hepatocellular carcinoma, and patients with acute HBV infection may have only mild, nonspecific symptoms. Therefore, understanding how this virus causes extrahepatic complications can help clinicians consider this possibility in patients with diverse symptom presentations. The pathophysiology of these extrahepatic disorders likely involves immune-related tissue injury following immune complex formation and inflammatory cascades. In some cases, direct viral infection of extrahepatic tissue may cause a clinical syndrome. Currently, the American Association for the Study of Liver Diseases recommends treatment of chronic HBV infections with interferon therapy and/or nucleos(t)ide analogs, and this treatment has been reported to improve some extrahepatic disorders in some patients with chronic HBV infection. These extrahepatic complications have a significant role in disease outcomes and increase medical costs, morbidity, and mortality. Therefore, understanding the frequency and pathogenesis of these extrahepatic complications provides important information for both specialists and nonspecialists and may help clinicians identify patients at an earlier stage of their infection.

Ultrasensitive Label-Free Electrochemical Immunosensor for Carbohydrate Antigen-125 (CA125) Employing Cu(II)-Polyethyleneimine (PEI)/Silica Nanoparticle@Overoxidized Polypyrrole (OPPy)/Multi-Walled Carbon Nanotubes (MWNTs) Hybrid Nanomaterial

Novel electroactive nanotags of Cu(II) functionalized polyethylenimine (PEI)/SiO2 nanoparticles (abbreviated as Cu2+/PEI/SiO2 NPs) were conveniently synthesized using a strong coordination reaction between Cu(II) and the multi-amino groups of PEI. These electroactive nanotags were easily coated on the overoxidized polypyrrole (OPPy) modified Nafion/multi-walled carbon nanotubes (abbreviated as Nafion/MWNTs) electrode surface through Cu-N bonds and strong electrostatic interactions. The Cu2+/PEI/SiO2 NPs@OPPy/MWNTs hybrid nanomaterial was formed without the addition of extra membrane-forming substances. The experimental results demonstrate that the OPPy/MWNTs composite membrane coupled with electrocatalytic Cu(Tris)4 2+ complexes in tris(hydroxymethyl)aminomethane (Tris)-HCl buffer medium amplified the electrochemical signals of nanotags based on the mutual synergistic effects. As an application, a label-free electrochemical immunosensor for epithelial ovarian cancer biomarker-carbohydrate antigen-125 (CA125) was constructed by covalently immobilizing CA125 antibody onto the hybrid nanomaterial modified electrode. With the increasing concentrations of CA125 antigen, different decreases in the electrochemical signals of the nanotags were observed due to the formation of antigen-antibody immune complexes. The electrochemical immunosensor showed a linear relationship from 0.001 to 500 U·mL−1 for CA125 with a detection limit of 3.4 × 10−4 U·mL−1. In addition, the proposed immunosensor was applied to the determination of CA125 in human serum with satisfactory results.

Novel assay format for total anti-adeno-associated virus antibody detection with low capsid consumption and built-in specificity control.

Aim: To develop an assay format for detection of total anti-adeno-associated virus 2 (AAV2) antibodies with low capsid material consumption. Methods: An immune complex (IC) assay format was developed. The format is based on the formation of ICs in solution and their subsequent detection using an anti-AAV2 antibody for capture and an antibody against the study species IgG for detection. Results: The feasibility of the IC assay for detection of preexisting and treatment-emergent anti-AAV2 antibodies was demonstrated in cynomolgus monkey and human serum samples, including samples from a preclinical study with AAV2-based therapies. Conclusion: The presented IC assay is an easy-to-perform total anti-AAV2 antibody assay that requires a small amount of unlabeled capsid material and provides an intrinsic specificity control.

Biodistribution of Drug/ADA Complexes: The Impact of Immune Complex Formation on Antibody Distribution

The clinical use of therapeutic monoclonal antibodies (mAbs) for the treatment of cancer, inflammation, and other indications has been successfully established. A critical aspect of drug-antibody pharmacokinetics is immunogenicity, which triggers an immune response via an anti-drug antibody (ADA) and forms drug/ADA immune complexes (ICs). As a consequence, there may be a reduced efficacy upon neutralization by ADA or an accelerated drug clearance. It is therefore important to understand immunogenicity in biological therapies. A drug-like immunoglobulin G (IgG) was radiolabeled with tritium, and ICs were formed using polyclonal ADA, directed against the complementary-determining region of the drug-IgG, to investigate in vivo biodistribution in rodents. It was demonstrated that 65% of the radioactive IC dose was excreted within the first 24 h, compared with only 6% in the control group who received non-complexed 3H-drug. Autoradiographic imaging at the early time point indicated a deposition of immune complexes in the liver, lung, and spleen indicated by an increased radioactivity signal. A biodistribution study confirmed the results and revealed further insights regarding excretion and plasma profiles. It is assumed that the immune complexes are readily taken up by the reticuloendothelial system. The ICs are degraded proteolytically, and the released radioactively labeled amino acids are redistributed throughout the body. These are mainly renally excreted as indicated by urine measurements or incorporated into protein synthesis. These biodistribution studies using tritium-labeled immune complexes described in this article underline the importance of understanding the immunogenicity induced by therapeutic proteins and the resulting influence on biological behavior.Graphical Created with BioRender.com

Management of guillain-barré syndrome patients with type 2 respiratory failure in RSUD Gambiran

Guillain-Barré syndrome (GBS) is an autoimmune disorder that affects the peripheral nervous system. Most patients with GBS are clinically characterized by tetraplegia with or without sensory disturbances. In GBS this is due to a hyperreactive immune response including the release of anti-ganglioside antibodies, the formation of antibody-dependent immune complexes, and an increase in macrophages that cause demyelination and axonal degeneration. In severe cases GBS can appear clinically progressive with respiratory muscle involvement requiring mechanical ventilation and treatment in the intensive care unit. The patient we report is a 24 year old man with clinical type 2 respiratory failure with suspicion of GBS who was initially examined at the RSUD Kilisuci, then referred to the RSUD Gambiran and treated in the ICU at the RSUD Gambiran and received immunomodulatory therapy in the form of plasma exchange (PE). The patient was treated for 10 days in the ICU at RSUD Gambiran with the outcome being that the patient was able to move to the ward.

Renal Injury During Viral Infections

Renal pathologies following viral infections have become an emerging public health problem in both developed and developing countries. Diagnostic criteria are complex. In most cases, they involve correlation between clinical, biological and histological data, with occasional recourse to molecular biology techniques. Several mechanisms are involved in the pathogenesis of virus-related nephropathy, including virus tropism in the kidney, formation of immune complexes in situ or in the bloodstream, direct cytopathogenic effects, and multiple organ failure. The hepatitis C virus is responsible for three main types of kidney disease: membranoproliferative glomerulnephritis, cryoglobulinemia and membranous nephropathy. Hepatitis B virus is associated with membranous nephropathy, membranoproliferative glomerulnethritis, and IgA nephropathy. HIV (human immunodeficiency virus) infection is associated with several glomerular and tubular kidney damage. HIVAN (HIV-associated nephropathy), a specific entity mainly affecting Africans and African-Americans, presents as a rapidly progressive glomerulonephritis rapidly progressing to the terminal stage. Infections secondary to adenovirus, cytomegalovirus, epstein-barr virus, poliomavirus and coronavirus are often responsible for acute or chronic tubulointerstitial nephritis. Treatment is mainly symptomatic, based on nephroprotection measures, rarely combined with antiviral therapy. Prophylaxis with vacci-nation, when available, remains the best means of preventing viral nephropathy.

The role of BAFF and APRIL in IgA nephropathy: pathogenic mechanisms and targeted therapies.

Immunoglobulin A nephropathy (IgAN), characterized by mesangial deposition of galactose-deficient-IgA1 (Gd-IgA1), is the most common biopsy-proven primary glomerulonephritis worldwide. Recently, an improved understanding of its underlying pathogenesis and the substantial risk of progression to kidney failure has emerged. The "four-hit hypothesis" of IgAN pathogenesis outlines a process that begins with elevated circulating levels of Gd-IgA1 that trigger autoantibody production. This results in the formation and deposition of immune complexes in the mesangium, leading to inflammation and kidney injury. Key mediators of the production of Gd-IgA1 and its corresponding autoantibodies are B-cell activating factor (BAFF), and A proliferation-inducing ligand (APRIL), each playing essential roles in the survival and maintenance of B cells and humoral immunity. Elevated serum levels of both BAFF and APRIL are observed in patients with IgAN and correlate with disease severity. This review explores the complex pathogenesis of IgAN, highlighting the pivotal roles of BAFF and APRIL in the interplay between mucosal hyper-responsiveness, B-cell activation, and the consequent overproduction of Gd-IgA1 and its autoantibodies that are key features in this disease. Finally, the potential therapeutic benefits of inhibiting BAFF and APRIL in IgAN, and a summary of recent clinical trial data, will be discussed.

Ultrasensitive Detection of PSA Using Antibodies in Crowding Polyelectrolyte Multilayers on a Silicon Nanowire Field-Effect Transistor.

Immunosensors based on field-effect transistors with nanowire channels (NWFETs) provide fast and real-time detection of a variety of biomarkers without the need for additional labels. The key feature of the developed immunosensor is the coating of silicon NWs with multilayers of polyelectrolytes (polyethylenimine (PEI) and polystyrene sulfonate (PSS)). By causing a macromolecular crowding effect, it ensures the "soft fixation" of the antibodies into the 3-D matrix of the oppositely charged layers. We investigated the interaction of prostate-specific antigen (PSA), a biomarker of prostate cancer, and antibodies adsorbed in the PEI and PSS matrix. In order to visualize the formation of immune complexes between polyelectrolyte layers using SEM and AFM techniques, we employed a second clone of antibodies labeled with gold nanoparticles. PSA was able to penetrate the matrix and concentrate close to the surface layer, which is crucial for its detection on the nanowires. Additionally, this provides the optimal orientation of the antibodies' active centers for interacting with the antigen and improves their mobility. NWFETs were fabricated from SOI material using high-resolution e-beam lithography, thin film vacuum deposition, and reactive-ion etching processes. The immunosensor was characterized by a high sensitivity to pH (71 mV/pH) and an ultra-low limit of detection (LOD) of 0.04 fg/mL for PSA. The response of the immunosensor takes less than a minute, and the measurement is carried out in real time. This approach seems promising for further investigation of its applicability for early screening of prostate cancer and POC systems.

P264 The utility of ANCA in Ulcerative Colitis and Crohn’s Disease: A Retrospective Cohort Study in Taiwan

Abstract Background Inflammatory bowel disease (IBD) includes two chronic idiopathic inflammatory diseases: ulcerative colitis (UC) and Crohn disease (CD). The diagnosis of IBD depends on clinical, endoscopic, histological, radiological and biochemical criteria, which may be invasive, time consuming and usually not accepted by patients with IBD. Antineutrophil cytoplasmic antibodies (ANCAs) is believed to be related to IBD. The aim of this study was to investigate these serological markers and the evidence for their use in the diagnosis and management of IBD in Taiwan. Methods We conducted a retrospective cohort study in adult IBD patients who had received the serum examinations using the medical records of China Medical University Hospital between 1 January 1980 and 31 October. 2023. Results A total of 301 IBD patients (194 with UC, 107 with CD) were included in this current study. A high proportion were male (IBD 70.41%; UC 65.63%, and CD 76.71%). The mean diagnostic age of these enrolled patients was 42.9 years. In our patients, the prevalence of positive anti-HCV Ab is 0.0% in UC patients and 0.96% in CD patients. However, the prevalence of positive HBsAg was 14.5% in UC patients and 9.4% in CD patients. The prevalence of pANCA was 21.2% in UC patients and 1.4% in CD patients, respectively. The prevalence of cANCA was 3.1% in UC patients and 0.0% in CD patients. This pattern of low sensitivity and high specificity for pANCA is also seen in UC patients in various cohort studies. The serum positivity of p-ANCA was significantly higher in UC patients (Figure 1). UC patients with positive p-ANCA were older than CD patients with positive p-ANCA (44.9 vs. 37.3 years). Furthermore, we found that the incidence of positive p-ANCA in UC patients with E1, E2, and E3 at diagnosis was 3.5%, 39.2%, and 57.1%, respectively (Table 1). The serum levels of ANCA-IgG were indeed higher in patients in the severe group than those in the moderate and mild groups. Conclusion Serological biomarkers have been demonstrated to be a series of rapid, non-invasive approaches for assessments of early diagnosis, disease activity and prognosis for IBD. ANCA may be helpful in the early diagnosis of UC and in differentiating it from CD. UC patients with positive ANCA have a higher rate of intestinal mucosal vasculitis than UC patients with negative ANCA. Furthermore, ANCA may also contributes to the pathogenesis of HBV-related systemic vasculitis. Therefore, the management of HBV-related vasculitis includes control the immune complex formation and reaction as well as antiviral agents to reduce the antigenic load resulting in reduction of inflammation. Moreover, effective biomarkers with high sensitivity and specificity need to be investigated in the future.

ImmunoglobulinA vasculitis

The immune-mediated small vessel vasculitis is known as Schoenlein-Henoch purpura predominantly from pediatrics and in these cases occurs more frequently after infections of the upper airways. In adults, immunoglobulinA (IgA) vasculitis often proceeds more severely und recurrently with the classical tetrad of skin manifestations in the sense of leukocytoclastic vasculitis, joint affection, gastrointestinal involvement and IgA nephritis, in contrast to the mostly mild and self-limiting course in children. The background of this systemic vasculitis with formation of IgA immune complexes is considered to be an altered glycosylation of IgA, as this causes the exposure of binding sites for autoantibodies so that an immune complex reaction can be elicited. This ultimately leads to perivascular deposition of IgA and afurther activation of neutrophils. Groundbreaking in the diagnostics is the histological detection of leukocytoclastic vasculitis and in cases of renal manifestations akidney biopsy with characteristic deposits of immune complexes, which cannot be clearly differentiated from IgA nephropathy. The treatment is aimed at the respective manifestation and is mostly based on consensus recommendations due to the lack of randomized studies. In addition to immunosuppressive medication, in the presence of achronic kidney disease general nephroprotection is becoming increasingly more important also by inhibition of sodium-glucose transporter2 (SGLT2). The type and extent of kidney involvement and also rare cardiac manifestations are the main determinants of the prognosis. Continuous medical accompaniment of those affected is necessary due to the possible progression of the disease and the risk of recurrence.