Complement Activation Research Articles

Complement activation by IgM autoantibodies linked to immune-mediated neuropathies depends on C2.

Complement factor C2 is a potential therapeutic target in immune-mediated neuropathies. However, literature suggests that classical complement pathway activation may proceed to C3 in the absence of C2, a so-called "C2 bypass." Here, we evaluated a C2 bypass mechanism during complement activation by pathogenic human IgM from patients with immune-mediated neuropathies. IgM autoantibodies from 51 patients with multifocal motor neuropathy (MMN) or anti-myelin-associated glycoprotein (MAG) neuropathy (AMN) were used to activate complement in exvivo disease models. C2 bypass was evaluated using C2-depleted (C2D) serum and a therapeutic anti-C2 antibody. In two different disease models of MMN, IgM anti-GM1 and IgM anti-GM2 autoantibodies from MMN patients were bound to induced pluripotent stem cell-derived motor neurons and Schwann cells, respectively, and fixed C3 upon incubation with fresh serum. C3 fixation was inhibited by anti-C2 and did not occur with C2D serum. Similarly, in an AMN model, IgM anti-MAG antibodies were incubated with fresh serum fixed C3, which in all cases was abrogated in the absence of C2 or in the presence of anti-C2. In exvivo disease models of MMN and AMN, complement activation by IgM autoantibodies from 51 patients was in all cases dependent on C2 and was inhibited by an antihuman C2 antibody. No evidence of a C2 bypass mechanism was found.

Whole-blood model reveals granulocytes as key sites of dengue virus propagation, expanding understanding of disease pathogenesis.

Dengue virus (DENV) infection poses a significant global health threat, yet our understanding of its immunopathogenesis remains incomplete due to limitations of existing models. Here, we establish an in vitro whole-blood model using hirudin, an anticoagulant that preserves complement activity and cellular interactions, to study DENV infection. Our model reveals the susceptibility of all major leukocyte populations to DENV infection, with monocytes and granulocytes demonstrating high permissiveness and production of infectious virus progeny. Notably, granulocytes emerge as previously unrecognized targets of DENV infection, highlighting the importance of studying viral tropism within a physiologically relevant context. We also observed efficient DENV binding to B cells, but limited production of infectious virus, suggesting a potential role in viral sequestration or immune dysregulation. Interestingly, both NK and T cells, while less permissive, were also found to be susceptible to DENV infection. Our ex vivo analysis of whole blood from DENV-infected patients confirms the susceptibility of granulocytes, monocytes, B cells, natural killer cells, and T cells to infection, further validating the clinical relevance of our model. Additionally, we observed dynamic changes in circulating blood cell populations during acute dengue, potentially reflecting both direct virus-mediated effects and immune responses. This whole-blood model offers a valuable tool for investigating the complex interplay between DENV and host factors, facilitating a deeper understanding of dengue pathogenesis and ultimately contributing to the development of novel therapeutic strategies.IMPORTANCEDengue virus (DENV) infection is a significant global health threat, with increasing incidence in endemic regions and expanding geographic range due to factors like global warming. Current models for studying DENV pathogenesis often lack the complexity of the human immune system, hindering the development of effective therapies and vaccines. To address this, we have established the first in vitro whole-blood model using hirudin, preserving critical immune components and cellular interactions. This model reveals granulocytes as previously unrecognized targets of productive DENV infection, challenging existing paradigms of viral tropism. Our ex vivo analysis of patient blood samples confirms the clinical relevance of this finding and validates our model's utility. This unique model offers a powerful platform for future studies to dissect the complex interactions between DENV and the host immune system, including the roles of different leukocyte populations, ultimately informing the development of novel therapeutic strategies to combat this devastating disease.

Cushing's syndrome and COVID-19.

This review aims to present current data on the course of COVID-19 in patients with Cushing syndrome (CS) and discuss treatment for CS during to the pandemic. Literature review using PubMed (pubmed.ncbi.nlm.nih.gov). The search included the following terms: "COVID19" in combination with "Cushing syndrome", "Hypercortisolism" and "Glucocorticoid". Chronic hypercortisolism has been reported to increase infectious risk and worsens prognostic of patients with COVID-19 potentially due to its direct impact on the immune system: lymphopenia, impairment of monocytes and neutrophils activity, diminution of complement activation. Main metabolic complications of CS - i.e. diabetes, hypertension and obesity - have been recognized as COVID-19 complications risk factors. Patients with CS treated with steroidogenesis inhibitors might experience adrenal insufficiency during COVID-19. Special attention should be paid to patients with CS and COVID-19. The pandemic has impacted - and delayed - care of chronic illnesses including CS. Specific recommendations had been provided during the pandemic: favor telemedicine consultations, limit in-hospital explorations and postpone surgery when feasible. There are enough evidence for an increased prevalence and severity of COVID-19 to recommend a specific attention and caution in patients with CS.

Africanized honeybee venom (Apis mellifera) promotes human complement activation split products storm

IntroductionComplement activation split products are signatures of many immunopathological disorders. Among the laboratory findings observed in these diseases, a reduction in the level of circulating intact complement components can be mentioned, and this change has also been detected in envenomation by multiple Africanized honeybee (Apis mellifera) stings. Although envenomation by these animals elicits diverse life-threatening reactions, the capacity of bee venom (AmV) to activate the human complement system remains elusive.Methods and findingsBy coupling immunochemical and functional approaches, it was observed that AmV strongly consumes components of the alternative pathway (AP) of the complement system in normal human serum (NHS). Additionally, AmV interfered with classical (CP) and lectin pathways (LP) activities. In parallel, a high increase in Ba fragment levels was detected, suggesting that the changes in AP activity were due to its activation. Furthermore, an increase in the level of the C1s-C1INH complex and a decrease in the physiological level of MASP1-C1INH suggested that CP and LP were also activated in the presence of AmV. Strikingly, NHS exposed to increasing AmV concentrations varying from 5 to 1000 µg/mL presented a high generation of C3a, C4a and C5a anaphylatoxins, and sC5b-9 complexes assembly, thus reinforcing that AmV triggers complement activation.ConclusionThese results show that AmV is a strong complement activator. This activation presents a mixed profile, with a predominance of AP activation. This suggests that complement split products can play important roles in the envenomation by Africanized honeybee, as they could induce diverse immunopathological events observed in patients and may also dictate patient clinical prognosis.

Proteomic Profiling of COVID-19 Patients Sera: Differential Expression with Varying Disease Stage and Potential Biomarkers

Background/Objectives: SARS-CoV-2 is one of the viruses that caused worldwide health issues. This effect is mainly due to the wide range of disease prognoses it can cause. The aim of this study is to determine protein profiles that can be used as potential biomarkers for patients’ stratification, as well as potential targets for drug development. Methods: Eighty peripheral blood samples were collected from heathy as well as SARS-CoV-2 patients admitted at a major tertiary care center in Riyadh, Saudi Arabia. A label-free quantitative mass spectrometry-based proteomic analysis was conducted on the extracted sera. Protein–protein interactions and functional annotations of identified proteins were performed using the STRING. Results: In total, two-hundred-eighty-eight proteins were dysregulated among all four categories. Dysregulated proteins were mainly involved in the network map of SARS-CoV-2, immune responses, complement activation, and lipid transport. Compared to healthy subjects, the most common upregulated protein in all three categories were CRP, LGALS3BP, SAA2, as well as others involved in SARS-CoV-2 pathways such as ZAP70 and IGLL1. Notably, we found fifteen proteins that significantly discriminate between healthy/recovered subjects and moderate/under medication patients, among which are the SERPINA7, HSPD1 and TTC41P proteins. These proteins were also significantly downregulated in under medication versus moderate patients. Conclusions: Our results emphasize the possible association of specific proteins with the SARS-CoV-2 pathogenesis and their potential use as disease biomarkers and drug targets. Our study also gave insights about specific proteins that are likely increased upon infection but are likely restored post recovery.

Acquired and genetic drivers of C3 and C5 convertase dysregulation in C3 glomerulopathy and immunoglobulin-associated MPGN.

Dysregulation of the alternative pathway of complement plays a central role in the pathophysiology of C3 Glomerulopathy (C3G). Various autoimmune and genetic factors targeting the alternative pathway have been associated to both C3G and primary Immunoglobulin-associated Membranoproliferative Glomerulonephritis (Ig-MPGN), suggesting shared pathophysiological mechanisms. This review highlights the wide range of disease drivers identified that mainly target components or protein complexes of the alternative pathway, both in C3G and Ig-MPGN. Nephritic factors, which constitute a heterogeneous group of autoantibodies targeting the C3 or the C5 convertase, are the most common abnormalities. Monoclonal gammopathies are frequent in aging adults. They may promote complement activation and have in some cases also found to target alternative pathway regulatory proteins. Additionally, some patients with C3G and Ig-MPGN carry rare variants in genes encoding complement activating or regulating proteins of the alternative pathway. This review provides an informative overview of pathogenetic mechanisms associated with each abnormality, acting at different steps in the complement cascade. The diversity of targets involved in the C3G pathophysiology suggests the potential benefit of therapeutical approaches tailored to the underlying disease drivers, with a pivotal impact upstream or at the level of the C3 or C5 convertase activity.

Acquired and genetic determinants of disease phenotype and therapeutic strategies in C3 glomerulopathy and immunoglobulin-associated MPGN.

C3 glomerulopathy (C3G), a prototype of complement mediated disease, is characterized by significant heterogeneity, not only in terms of clinical, histological and biological presentation but also of prognosis, and response to existing therapies. Recent advancements in understanding the factors responsible for alternative pathway dysregulation in the disease have highlighted its even more complex nature. Here, we propose a reexamination of the diversity of C3G presentations in light of the drivers of complement activation. Autoantibodies targeting complement proteins, genetic abnormalities in complement genes and monoclonal immunoglobulins are now well-known to drive disease occurrence. This review discusses how these drivers contribute to the heterogeneity in disease phenotype and outcomes, providing insights into tailored diagnostic and therapeutic approaches. In recent years, a broad spectrum of complement inhibitory therapies has emerged, soon to be available in clinical practice. The recognition of specific clinical, biological, and histological patterns associated with different forms of C3G is crucial for personalized management, particularly treatment strategies.

Complement and microglia activation mediate stress-induced synapse loss in layer 2/3 of the medial prefrontal cortex in male mice.

Spatially heterogeneous synapse loss is a characteristic of many psychiatric and neurological disorders, but the underlying mechanisms are unclear. Here, we show that spatially-restricted complement activation mediates stress-induced heterogeneous microglia activation and synapse loss localized to the upper layers of the medial prefrontal cortex (mPFC) in male mice. Single cell RNA sequencing also reveals a stress-associated microglia state marked by high expression of the apolipoprotein E gene (Apoehigh) localized to the upper layers of the mPFC. Mice lacking complement component C3 are protected from stress-induced layer-specific synapse loss, and the Apoehigh microglia population is markedly reduced in the mPFC of these mice. Furthermore, C3 knockout mice are also resilient to stress-induced anhedonia and working memory behavioral deficits. Our findings suggest that region-specific complement and microglia activation can contribute to the disease-specific spatially restricted patterns of synapse loss and clinical symptoms found in many brain diseases.

The Impact of the Histone Deacetylase Inhibitor-Sodium Butyrate on Complement-Mediated Synapse Loss in a Rat Model of Neonatal Hypoxia-Ischemia.

Perinatal asphyxia is one of the most important causes of morbidity and mortality in newborns. One of the key pathogenic factors in hypoxic-ischemic (HI) brain injury is the inflammatory reaction including complement system activation. Over-activated complement stimulates cells to release inflammatory molecules and is involved in the post-ischemic degradation of synaptic connections. On the other hand, complement is also involved in regenerative processes. The histone deacetylase inhibitor (HDACi)-sodium butyrate (SB)-provides reduction of inflammation by decreasing the expression of the proinflammatory factors. The main purpose of this study was to examine the effect of SB treatment on complement activation and synapse elimination after HI. Neonatal HI was induced in Wistar rats pups by unilateral ligation of the common carotid artery followed by 60-min hypoxia (7.6% O2). SB (300mg/kg) was administered on a 5-day regimen. Our study has shown decreased levels of synapsin I, synaptophysin, and PSD-95 in the hypoxic-ischemic hemisphere, indicating synaptic loss after neonatal HI. Transmission electron microscopy revealed injury of the synaptic structures in the brain after HI. SB treatment increased the level of the synaptic proteins, improved tissue ultrastructure, and reduced degradation of the synapses. Neonatal HI induced mRNA expression of the complement C1q, C3, C5, and C9, and their receptors C3aR and C5aR. The effect of SB was different depending on the time after induction of hypoxic-ischemic damage. Our study demonstrated that neuroprotective effect of SB may be related to the modulation of complement activity after HI brain injury.

Praziquantel and factor H recruitment differentially affect the susceptibility of Schistosoma mansoni to complement-mediated damage

BackgroundSchistosomes are highly efficient evaders of human immunity, as evident by their ability to survive in human blood for years. How they protect themselves against the constant attack by a key element of innate immunity, the complement system, has remained unclear. In this study, new light is shed on the interaction between distinct life-cycle stages of Schistosoma mansoni and the human complement system.ResultsWe demonstrate that schistosomula, the young stage assumed immediately after cercaria penetration of the skin, are extremely vulnerable towards complement-mediated killing as only 10-20% survive. The survival rate increases to 70% already within 30 minutes and reaches close to 100% within two hours. Pathway-specific complement inhibitors revealed the alternative pathway of complement activation as the main contributor to killing and damage of the schistosomula. Moreover, the complement regulator factor H is recruited by the schistosomula in this early stage to evade killing. Surviving parasites appear fully viable despite the ongoing complement attack, as demonstrated by the deposition of C3 fragments. However, when exposed to the widely used schistocidal drug praziquantel, the vulnerability of 24 h-old schistosomula towards complement-mediated killing is notably increased; no such effect was observed for mefloquine or oxamniquine. Similar to the younger life-cycle stages, adult worms remain under complement attack. C3 fragments were found all over the outer surface (tegument), deposited mostly on the ridges and not on the tubercles.ConclusionThe recruitment of factor H merits more detailed studies that pinpoint the molecules involved and elucidate the novel possibilities to intercept the uncovered immune evasion therapeutically. That praziquantel and complement work in synergy is surprising and may in the future result in enhanced understanding of the drug’s mechanism of action.

IMMU-31. DAMAGE RESPONSE FROM SYSTEMIC RNA VACCINATION RESTORES HUMORAL IMMUNITY IN GLIOBLASTOMA

Abstract Therapies against glioblastoma (GBM) remain stymied by poor penetration across the blood-brain barrier (BBB) and systemic immunotolerance. These outcomes necessitate development of therapies simultaneously targeted to tumors while engineering peripheral immunity to co-localize for synergistic responses. We developed RNA loaded lipid particles (LPs) to simultaneously function as inducers of cytotoxic responses in the GBM tumor microenvironment (TME) and as systemic activators of peripheral immunity. RNA-LP mediated response was studied in mice bearing KR158b tumors and in canines and humans with spontaneous glioma and glioblastoma respectively. We found that RNA-LPs could localize to the brain TME of animals bearing murine gliomas and rapidly upregulate damage associated signaling pathways including p53-CDKN2A. This correlates with increased gene signatures for complement and proteosome processing. Simultaneously, in the periphery, RNA-LPs increase integrin expression on activated T cells and ICAM expression in brain tumors helping steer T cell translocation across the BBB. In canines with malignant gliomas, response to RNA-LPs correlated with increasing tumor size suggesting pseudoprogression. Similar to murine glioma, canine gliomas harvested within 48h of vaccine administration demonstrated rapid increases in complement and p53 pathway activation. In one human patient treated with RNA-LPs per NCT04573140 (PNOC020 trial), we demonstrate biopsy confirmed pseudoprogression with increases in p53 pathway signaling and complement activation. In post-treatment tumor biopsy samples, there was increased hyperexpanded post-infusion intratumoral IgH clones. Systemic administration of RNA-LP elicits damage response in the TME that predisposes complement activation and humoral immunity. Coupled with peripheral recruitment of T cells that can translocate across the BBB, RNA-LPs elicit potent bi-directional adaptive immunotherapy against GBM.

Thrombosis in Paroxysmal Nocturnal Hemoglobinuria (PNH): From Pathogenesis to Treatment

Paroxysmal Nocturnal Hemoglobinuria (PNH) constitutes a rare bone marrow failure syndrome characterized by hemolytic anemia, thrombotic events (TEs), and bone marrow aplasia of variable degrees. Thrombosis is one of the major clinical manifestations of the disease, affecting up to 40% of individuals with PNH. Venous thrombosis is more prevalent, affecting mainly unusual sites, such as intrabdominal and hepatic veins. TEs might be the first clinical manifestation of PNH. Complement activation, endothelial dysfunction, hemolysis, impaired bioavailability of nitric oxide, and activation of platelets and neutrophils are implicated in the pathogenesis of TEs in PNH patients. Moreover, a vicious cycle involving the coagulation cascade, complement system, and inflammation cytokines, such as interleukin-6, is established. Complement inhibitors, such as eculizumab and ravulizumab (C5 inhibitors), have revolutionized the care of patients with PNH. C5 inhibitors should be initiated in patients with PNH and thrombosis, while they constitute a great prophylactic measure for TEs in those individuals. Anticoagulants, such as warfarin and low-molecular-weight heparin, and, in selected cases, direct oral anticoagulants (DOACs) should be used in combination with C5 inhibitors in patients who develop TEs. Novel complement inhibitors are considered an alternative treatment option, especially for those who develop extravascular or breakthrough hemolysis when terminal inhibitors are administered.

Monocyte/macrophage pyroptosis and C5b-9-induced cyst enlargement in Pkd1-/- mice.

The levels of C5b-9, terminal products of complement activation, were significantly elevated in autosomal dominant polycystic kidney disease (ADPKD). However, the precise mechanisms by which C5b-9 facilitates cyst growth remain incompletely elucidated. Three groups of chronic-onset Pkd1-/- mice were established: one group received intravenous injections of 0.5 mg/kg C5b-9, another was administered 1.0 mg/kg monoclonal anti-C9 antibodies, and a control group received 1 mg/kg IgG isotype control (IC). All treatments were administered biweekly for two months (postnatal day [PD] 180-240). Renal macrophages from distinct subsets were sorted using fluorescence-activated cell sorting (FACS). To deplete macrophages, liposome clodronate (LC) was injected intraperitoneally. Sublethal irradiation followed by bone marrow (BM) reconstruction was performed in Pkd1-/- mice to evaluate the role of BM-derived macrophages (BMDMs) in ADPKD progression. (1) In vitro, sublytic C5b-9 did not affect the viability of renal tubular epithelial cells (RTECs), but significantly induced M1-like polarization and pyroptosis of BMDMs. (2) In vivo, C5b-9 notably triggered pyroptosis of Ly6C+ monocytes and a reduction in circulating monocyte numbers as cysts enlarged. (3) Residual Ly6C+ monocytes infiltrated renal tissues and differentiated into Ly6C+ macrophages, which exhibited a greater susceptibility to pyroptosis compared to Ly6C- macrophages. (4) Although limited evidence has recently suggested that Ly6C- monocytes may also be affected by C5b-9, upregulation of CCR2 in Ly6C- macrophages was observed in C5b-9-treated Pkd1-/- mice, implying that Ly6C- monocytes could represent a significant source of M2 macrophages. C5b-9 infusion promoted RTEC proliferation by inducing pyroptosis of Ly6C+ monocytes/macrophages, contributing to progressive cyst enlargement in chronic-onset PKD mice.

Prognostic value of serum complement cleavage factor Bb in idiopathic membranous nephropathy and establishment of nomogram model

Complement activation is involved in idiopathic membranous nephropathy (IMN). We aimed to investigate the relationship of serum complement cleavage factor Bb with IMN progression, and to establish a model for early prediction of kidney outcomes. We measured serum factor Bb in a retrospective cohort of 449 IMN patients at the time of kidney biopsy. Cox regression analysis showed that higher levels of serum factor Bb were independently associated with IMN progression event defined as end-stage renal disease or ≥ 40% decline in estimated glomerular filtration rate. Patients in the middle and highest tertiles of serum factor Bb had respectively 2.1-, and 2.6-fold higher risk for disease progression compared with those in the lowest tertile. We developed an optimized prognostic nomogram model incorporating age, log serum anti-PLA2R antibody, log serum Bb, proteinuria and tubular atrophy/interstitial fibrosis. The model demonstrated good predictive ability with a concordance index of 0.77 (bootstrap-corrected of 0.76) for predicting 3-, and 5-year kidney survival. Calibration curves and decision curve analysis confirmed the model’s good calibration and clinical utility. Our findings suggest that serum factor Bb may serve as an essential prognostic indicator of IMN. The novel nomogram model may offer important guidance on the management of this patient population.

A Thrilling Case of Anemia

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare bone marrow failure disorder that presents with triad of peripheral blood cytopenias, hemolytic anemia and thrombosis. The absence of two glycosylphosphatidylinositol (GPI)-anchored proteins, CD55 and CD59, leads to uncontrolled complement activation that accounts for hemolysis and other PNH manifestations. GPI anchor protein deficiency is due to acquired somatic mutations in phosphatidylinositol glycan class A (PIGA) gene.Terminal complement inhibition with eculizumab and allogeneic bone marrow transplantation (BMT) are the only widely effective therapies for patients with classical PNH. Compared to eculizumab and ravulizumab that block the fifth component of complement (C5), pegcetacoplan blocks the third component of complement (C3).

Effect of wild-type vaccine doses on BA.5 hybrid immunity, disease severity, and XBB reinfection risk.

Vaccination against the wild-type (WT) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus did not produce detectable levels of neutralizing antibodies (NAbs) against the BA.5 strain before it emerged. However, coronavirus disease-2019 (COVID-19) severity varied highly between unvaccinated, partially vaccinated, and fully vaccinated individuals, for unknown reasons. We assessed the severity of BA.5 infection and the risk of XBB strain reinfection and measured serum levels of NAbs against WT, BA.5, and XBB.1.9.1 SARS-CoV-2 strains at varying time points in 1,373 individuals who received zero, one, two, or three WT vaccine doses. We found that two to three WT doses significantly increased WT and BA.5 NAb levels and reduced the incidence of COVID-19-associated pneumonia upon BA.5 strain infection compared to zero to one dose. Regarding XBB reinfection, those who received two to three doses and were infected with the BA.5 variant exhibited a significantly lower reinfection risk compared to those who received zero to one dose. RNA analysis revealed that the differentially expressed genes between the two to three dose and unvaccinated groups were enriched in B cell activation, cytokine-cytokine receptor interaction, complement, and monocyte activation functions-indicating that vaccination increased the antibody response and reduced inflammation. Our results suggest that multiple antigen exposures to either matched or unmatched SARS-COV-2 variants, through vaccination or infection, may be necessary to achieve significant immune imprinting.IMPORTANCEThe administration of coronavirus disease-2019 (COVID-19) vaccines that do not perfectly match the viral strains that individuals become infected with has been found to impact the resultant illness severity-although the precise mechanism underlying this phenomenon remains unclear. We assessed viral clearance, as well as serum levels of inflammatory cytokines and neutralizing antibodies (NAbs) against wild-type, BA.5, and XBB.1.9.1 variants of the severe acute respiratory syndrome coronavirus 2 among individuals who received varying doses of such strain-mismatched vaccines. Notably, vaccination with ≥2 doses of strain-mismatched COVID-19 vaccines appeared to stimulate the production of specific NAbs during infection with new variants, as well as attenuate the inflammatory response and enhance viral clearance. Such vaccination regimens can also reduce the risk of reinfection. These findings may be important for guiding the development of future COVID-19 vaccination strategies that target both matched and mismatched viral variants.

First, do no harm: the role of preclinical animal models in predicting adverse events in gene therapy clinical trials for Duchenne muscular dystrophy and X-Linked myotubular myopathy

The occurrence of severe adverse events (SAEs) in patients with Duchenne muscular dystrophy (DMD), X-linked myotubular myopathy (XLMTM), and other neuromuscular diseases treated with adeno-associated virus (AAV) constructs has prompted studies to improve the safety and efficacy of gene therapy. Physicians have weighed the medical tenet of “first, do no harm” against the perspective of patients with progressive life-threatening conditions who may accept greater risk. Regarding SAE pathogenesis, discussion has focused on total AAV exposure and patient mutations more likely to induce immunity, while stressing the limitations of animal models in predicting adverse events. Therapeutic strategies for reducing side effects have employed more myotropic AAV serotypes and efficient transgenes. Other recommendations include excluding certain DMD gene mutations associated with SAEs and substituting less immunogenic transgenes such as utrophin (DMD) and myotubularin-related protein (XLMTM). For the sake of preclinical studies, emphasis has been placed on outbred rodents and larger animals that better predict immunity. Here, the absence of side effects in canine DMD and XLMTM models might be explained partly by phenotypic differences between affected humans and dogs. Specifically, dystrophin- and myotubularin-deficient dogs exhibit milder lesions, including less muscle fat deposition and the absence of hepatopathy, respectively, which could lead to reduced immune responses to AAV constructs. To better predict future problems, thought should be given to tracking early subclinical markers of the innate immune response, especially complement activation. Regardless of steps taken to improve the predictive value of animal models for SAEs, some questions will only be answered through human clinical trials after carefully considering the risk-benefit ratio.

Consideration of the EXiLE test for predicting anaphylaxis after diclofenac etalhyaluronate administration

Diclofenac etalhyaluronate, an active pharmaceutical ingredient in JOYCLU® (JCL), serves as a joint function improvement agent in knee and hip osteoarthritis patients. However, frequent cases of anaphylaxis induced by JCL administration have been reported. Recent clinical research suggests the potential utility of the basophil activation test (BAT) in predicting JCL-induced anaphylaxis. Nonetheless, the BAT is deemed impractical for routine diagnostic testing due to complex procedures involving whole blood stimulation and flow cytometry-based analyses. In the study reported here, an IgE crosslinking-induced luciferase expression (EXiLE) test which uses patient sera without complicated procedures, was performed with patients who had received JCL, with or without subsequent anaphylactic symptoms. The results of this test were then compared with those of the BAT reported in a clinical research study. Of the six BAT-positive JCL-induced anaphylaxis-experienced patients, four were positive in the EXiLE test and all non-experienced patients were negative in both the BAT and EXiLE tests, thus illustrating a high concordance rate of 92.3%. Further validation of testing conditions is expected to improve these rates. Notably, complement inactivation treatment led to a positive EXiLE result in a BAT-negative patient. In conclusion, it appears that the EXiLE test exhibits promise as an alternative to BAT for predicting JCL-induced anaphylaxis, and in so doing offers a simpler diagnostic approach.

Torque Teno Virus Control by the Classical Pathway of Complement Activation-A Retrospective Analysis From a First-in-Human Trial Utilizing Sutimlimab.

Torque Teno virus (TTV) load is linked with the functionality of its host's immune system and has been proposed as a potential monitoring tool for immune-modulating therapy. However, the immunological mechanisms of TTV control are incompletely understood. To assess the effect of the classical complement pathway on TTV, 64 healthy volunteers and 10 kidney transplant recipients treated with the anti-C1s antibody sutimlimab were analyzed for serum TTV copy numbers (c/mL) by qPCR. Overall, a correlation was observed between the decrease in complement activity caused by sutimlimab and the TTV load increase (ρ = -0.367, p < 0.001). Subgroup analysis indicated a trend toward TTV load increase in healthy volunteers following the highest sutimlimab dose compared to baseline (100 mg/kg body weight; median 3.5 log10 c/mL, interquartile range [IQR] 2.8-4.4 vs. 2.9 log10 c/mL, 0.8-3.5; p = 0.063). Administering multiple lower doses (30 mg/kg) also showed a trend toward TTV load increase in healthy volunteers (1.8 log10 c/mL, 0-2.3 vs. 1.9, 1.3-2.8; p = 0.054) and a significant increase in transplant recipients (3.5 log10 c/mL, 3.0-6.1 vs. 4.1, 3.5-6.4; p = 0.004). This report suggests a role for the classical complement pathway in controlling TTV load.

Zirconia encrusted ceramic composite membrane for uremic toxins removal: Fabrication and assessment of biocompatibility

In this study, tubular zirconia composite membranes (ZM1-ZM3) were developed using low-cost tubular substrate which was prepared utilizing naturally available clay materials by an extrusion approach. The zirconia nanoparticles were encrusted on a low-cost tubular substrate using spray pyrolysis technique. The membranes were investigated for their biocompatibility in addition to pore size, chemical stability, water permeability, porosity, contact angle, thermogravimetric (TGA), and X-ray diffraction (XRD). Water permeability, pore size and porosity of optimized membrane (ZM3) were 3.05 × 10-4 ± 0.03 L.m-2.h-1.Pa-1, 119 ± 0.57 nm and 36 ± 0.12 %, respectively. Platelets adhesion and protein adsorption were measured to be 4630 ± 46 platelets.mm-2, and 1.05 ± 0.02 μg.cm-2 respectively, while the activated partial thromboplastin time (APTT) and prothrombin time (PT) were 80 ± 0.51 s and 27 ± 0.26 s, respectively. Complement activation C3 and C4 concentrations were assessed to be 76.2 ± 0.88 mg.dL-1 and 21.57 ± 0.80 mg.dL-1, respectively and hemolysis ratio was 0.31 ± 0.01 %. Moreover, the membrane had a considerable antifouling nature with a flux recovery ratio of 89.22 ± 0.58 %. Protein retention was found to be 81.14 ± 0.58 %, in addition to outstanding sieving coefficients of uremic toxins like urea (0.95 ± 0.005), creatinine (0.93 ± 0.004), and phosphate (0.90 ± 0.004). These findings suggest that the produced tubular zirconia composite membrane has the potency for hemofiltration.