Search Results (44)

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal hematopoietic stem cell disease characterized primarily by intravascular hemolysis, thrombosis, and bone marrow failure. Complement inhibitors are commonly used in clinical treatment and show limited efficacy, highlighting the urgent need to identify new therapeutic targets and explore alternative treatment strategies to provide theoretical guidance for clinical practice. Methods: We established a PNH cell model and constructed an miRNA–mRNA regulatory network to identify key miRNAs and core target genes. Single-cell sequencing data were analyzed to further clarify the critical genes. Finally, integrated drug database analysis identified potential therapeutic agents for PNH, which were validated by molecular docking and molecular dynamics simulations. Results: Using CRISPR/RNP technology, we successfully constructed a PIGA-knockout (PIGA-KO) THP-1 cell model. Differential expression analysis identified 1979 differentially expressed mRNAs (DEmRNAs) and 97 differentially expressed miRNAs (DEmiRNAs). The multiMiR package in R was used to predict the target genes of DEmiRNAs, from which those experimentally validated through dual-luciferase reporter assays were selected. After integration with the DEmRNAs, an miRNA–mRNA regulatory network was constructed, comprising 26 miRNAs and 38 mRNAs. Subsequent miRNA pathway enrichment analysis identified hsa-miR-23a-3p as a key miRNA, with CXCL12, CXCL8, HES1, and TRAF5 serving as core target genes. The integration of single-cell sequencing datasets (PRJNA1061334 and GSE157344) was performed, followed by cell communication and enrichment analysis. This approach, combined with clinical relevance, identified the neutrophil cluster as the key cluster. Intersection analysis of neutrophil cluster differential analysis results with key modules from hdWGCNA further clarified the critical genes. Drug prediction using EpiMed, CMap, and DGIdb identified Leflunomide, Dipyridamole, and Pentoxifylline as potential therapeutic agents. Molecular docking and molecular dynamics simulations showed stable binding of these potential drugs to the critical molecules, indicating a viable molecular interaction foundation. Conclusions: Leflunomide, Dipyridamole, and Pentoxifylline may serve as promising therapeutic agents for PNH, and the hsa-miR-23a-3p/CXCL8 regulatory axis could play a pivotal role in the pathogenesis and progression of PNH. Full article

Therapeutic antibodies have revolutionized hematology, offering targeted and effective treatments for both malignant and non-malignant diseases. In hematologic malignancies, anti-CD20, anti-CD19, anti-CD38, and anti–B-cell maturation antigen (BCMA) antibodies have markedly improved survival outcomes, whereas antibody–drug conjugates and bispecific antibodies continue to expand therapeutic possibilities. Besides cancer, complement inhibitors such as eculizumab, ravulizumab, and the recently approved crovalimab have redefined paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome management, and the bispecific antibody emicizumab has transformed prophylaxis in hemophilia A. Furthermore, novel antibody formats such as the trifunctional anti-CD38 × CD3 antibody (Tri-31C2) exhibit enhanced anti-myeloma activity compared to chimeric CD38 antibodies, underscoring the future potential of T-cell–redirecting designs. This review summarizes key developments in therapeutic antibodies for hematological disorders, their action mechanisms, and emerging strategies to further optimize their efficacy and safety. Full article

Glycosylphosphatidylinositols (GPIs) are complex glycolipids that function as membrane anchors for a wide array of eukaryotic proteins, collectively referred to as GPI-anchored proteins (GPI-APs). These structures are critical for various cellular processes including signal transduction, host–pathogen interactions, and immune evasion. While GPI-APs have been extensively studied, increasing attention is being paid to non-protein-linked GPI, called free GPIs, which have been identified in both protozoan parasites and mammalian cells. In protozoa such as Trypanosoma brucei, Trypanosoma cruzi, Toxoplasma gondii, Plasmodium falciparum, and Leishmania spp., free GPIs play roles in virulence, immune modulation, and parasite survival. In mammals, free GPIs have been detected in several tissues and pathogenic conditions of paroxysmal nocturnal hemoglobinuria caused by PIGT mutation and rare blood group phenotypes. This review provides a comparative overview of the structure and biosynthesis of free GPIs and GPI-APs across species, highlighting unique adaptations in each. We also discuss the emerging physiological and pathological roles of free GPIs, proposing that these underexplored molecules may serve as important biomarkers and therapeutic targets. Understanding the diversity and function of free GPIs offers new insights into glycobiology and host–pathogen interactions. Full article

Paroxysmal nocturnal hemoglobinuria (PNH) is associated with bone marrow failure disorders and may arise during the long-term follow-up of aplastic anemia (AA), which is named AA/PNH syndrome. Thrombosis is the most frequent clinical complication and is the main cause of mortality in PNH. However, thromboses tend to originate in hepatic and cerebral venous vessels, but rarely in the hepatic microvascular vein in PNH patients. Here, we report on a young man with hepatic sinusoidal obstruction syndrome (HSOS) secondary to AA/PNH syndrome. His main manifestations were hemolytic anemia, renal injury, ascites, hepatomegaly, and elevated liver enzymes. The diagnosis was confirmed by peripheral blood flow cytometry, enhanced computed tomography (CT), and liver biopsy. Initially, he received symptomatic treatments including diuretics, intermittent abdominal paracentesis, and low-molecular-weight heparin. Meanwhile, due to the occurrence of PNH activity during hospitalization, methylprednisolone 40 mg per day was administered, which was later transitioned to oral prednisolone. Subsequently, the dose of corticosteroids was gradually decreased once his hemoglobin stabilized. The association between HSOS and AA/PNH syndrome is exceptionally rare, as evidenced by the scant literature on the subject. This case underscores the critical need for awareness of HSOS secondary to AA/PNH syndrome, which needs a high index of suspicion and for which prompt treatment is needed to reduce morbidity and mortality. Full article

Complement factor 5 (C5) inhibitors for paroxysmal nocturnal hemoglobinuria (PNH) may cause iron overload due to residual intravascular hemolysis (IVH) and emergent extravascular hemolysis (EVH). In PEGASUS (phase 3; NCT03500549), adults with PNH with residual anemia (hemoglobin concentration < 10.5 g/dL) after ≥3 months of eculizumab received eculizumab and pegcetacoplan for 4 weeks and were then randomized (1:1) to eculizumab or pegcetacoplan monotherapy for 16 weeks; in the following 32-week, open-label period, patients either continued pegcetacoplan or switched from eculizumab to pegcetacoplan. This post hoc analysis reports PEGASUS transfusion-related data and iron-related biomarkers to evaluate pegcetacoplan’s effects on iron regulation. Of 80 patients randomized in PEGASUS, 27 (33.8%) had baseline iron overload (serum transferrin saturation ≥ 50%). Iron overload resolved within 52 weeks of pegcetacoplan treatment in 16 of 22 patients (72.7%) with baseline and postbaseline data; 10 experienced resolution after 20 weeks. With pegcetacoplan, transfusion numbers decreased for patients with and without iron overload, hepcidin concentrations increased, and absolute reticulocyte counts (ARCs) decreased to normal range. Mean ferritin concentrations were above normal throughout the study, regardless of iron overload status. Pegcetacoplan improves iron overload-related biomarkers, including increased hepcidin concentrations and decreased ARCs, by blocking IVH and EVH and preventing anemia. Full article

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired clonal hematologic disorder caused by somatic mutations in the PIGA gene of hematopoietic stem cells, leading to the absence of GPI-anchored proteins, including the complement regulators CD55 and CD59. This deficiency results in uncontrolled complement activation, causing intravascular and extravascular hemolysis, thrombosis, and bone marrow failure. Historically associated with substantial morbidity, PNH management has been transformed by the advent of complement inhibitors. Eculizumab, the first approved C5 inhibitor, significantly reduced thrombotic risk and improved survival but did not eliminate anemia due to extravascular hemolysis. Newer agents now target proximal complement components, offering broader control and improved convenience. This review summarizes the pathophysiology of PNH, evaluates established and emerging complement inhibitors, and discusses ongoing therapeutic challenges and future directions. Full article

Background/Objectives: The field of nephrology is increasingly embracing advanced treatments and clinical trials that focus on inhibiting specific components of the complement cascade, a key driver in complement-mediated kidney diseases. Materials and Methods: This review aims to summarize innovative therapies targeting various pathways, including the inhibition of the terminal part of the complement pathway (mainly C5), the alternative pathway (factor B inhibitors), and the lectin pathway (MASP inhibitors. C5 inhibitors play a critical role in preventing the formation of the membrane attack complex (MAC), offering effective solutions for conditions like atypical hemolytic uremic syndrome (aHUS) and paroxysmal nocturnal hemoglobinuria (PNH). Meanwhile, avacopan, a C5a receptor antagonist, addresses ANCA-associated vasculitis (AAV) by mitigating inflammation and enabling reduced reliance on corticosteroids. Similarly, narsoplimab, which inhibits MASP-2, targets the lectin pathway implicated in conditions such as aHUS. Iptacopan, a factor B inhibitor, focuses on the alternative pathway and demonstrates efficacy in managing C3 glomerulopathy (C3G). Results: A systematic review of complement-targeted therapies was conducted, analysing studies from 2013 to 2023 that address unmet medical needs in primary and secondary glomerular diseases. Conclusions: Our systematic review of complement-targeted therapies shows that these tailored and innovative treatments may specifically address unmet medical needs in primary and secondary glomerular diseases. Full article

Background/Objectives: This analysis was conducted in Italy to estimate the epidemiology of paroxysmal nocturnal hemoglobinuria (PNH) and to describe the features and economic burden of PHN in the adult population considering the role of anti-complement therapy with C5/3-inhibitors (C5/3i). Methods: Administrative databases of healthcare entities covering approximately 12 million citizens were used to estimate the prevalence and incidence of PNH. Demographics, clinical characteristics and healthcare costs were analyzed among adults with PHN stratified by the presence/absence of C5/3i therapy. Results: The prevalence in Dec-2021 of PNH in adults was 17.6/1,000,000 people, and the incidence rate in the period 2011–2022 was 1.5/1,000,000/year. In 142 patients with at least 12 months of data available before and after inclusion (mean age: 50.7 years; 45.8% males), 27% received C5/3i therapy. The main baseline comorbidities were aplastic anemia and other bone marrow failure syndromes, found in 10.6% of patients and more common in C5/3i-treated than untreated patients (18.4% vs. 7.7%). Cost analysis showed that the average cost per patient per year (PPPY) was EUR 41,084, mainly driven by drug expenses (87% of total costs), especially anti-complement therapy (80%). RBC transfusions were the most impactive item among the hospitalization costs (EUR 1982 of EUR 4284 PPPY). The C5/3i-treated cohort was associated with higher total costs (EUR 133,472 vs. EUR 8089, p < 0.001), mainly due to drug expenses (EUR 127,180 vs. EUR 3217, p < 0.001). Conclusions: This real-world analysis confirmed a rising PNH prevalence in Italy, aligning with global data. Despite available therapies, many patients face a high disease burden, suggesting potential benefits from novel treatments targeting upstream complement components. Full article

Thromboembolism (TE) is a major cause of morbidity and mortality in patients with paroxysmal nocturnal hemoglobinuria (PNH). This narrative review summarizes available evidence on TE in Asian patients with PNH and discusses practical considerations and challenges for preventing and managing PNH-associated TE in Asian populations. Evidence suggests that, compared with non-Asians, fewer Asian patients have a history of TE (3.6% vs. 8.9%, p < 0.01), receive anticoagulants (8.5% vs. 16.2%, p = 0.002), or die from TE (6.9% vs. 43.7%, p = 0.000). Independent predictors of TE include lactate dehydrogenase ≥ 1.5 × upper limit of normal, pain, and male sex. Clone size alone does not appear to be a reliable estimate of TE risk. D-dimer levels are a useful marker of hemostatic activation, although they are not specific to PNH. Complement inhibition reduces the incidence of TE, although it does not wholly eliminate TE risk. Eligibility criteria and access to complement inhibitors vary across Asia, with limited availability in some countries. Anticoagulation is required to treat acute TE events and for primary or secondary prophylaxis in selected patients. Physicians and patients must stay alert to the signs and symptoms of TE to ensure prompt and appropriate treatment. Full article

Paroxysmal nocturnal hemoglobinuria (PNH) clones can be identified in a significant proportion of patients with aplastic anemia (AA). Screening for PNH clones at the time of an AA diagnosis is recommended by national and international guidelines. In this report, an expert panel of physicians discusses current best practices and provides recommendations for managing PNH in patients with AA in the Asia–Pacific region. Plasma/serum lactate dehydrogenase (LDH) levels and reticulocyte count should be measured with every blood test. PNH clone size should be monitored regularly by flow cytometry, with on-demand testing in the event of a rise in LDH level ± reticulocyte count or development of symptoms such as thrombosis. Monitoring for PNH clones can guide the choice of initial AA treatment, although flow cytometry has resource implications which may present a challenge in some Asia–Pacific countries. The treatment of patients with both PNH and AA depends on which condition predominates; following PNH treatment guidelines if hemolysis is the main symptom and AA treatment guidelines if bone marrow failure is severe (regardless of whether hemolysis is mild or moderate). The expert panel’s recommendations on the monitoring and treatment of PNH in patients with AA are practical for healthcare systems in the Asia–Pacific region. Full article

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. Full article

Flow cytometry plays a fundamental role in the diagnosis of leukemias and lymphomas, as well as in the follow-up and evaluation of minimally measurable disease after treatment. In some instances, such as in the case of acute promyelocytic leukemia (APL), rapid diagnosis is required to avoid death due to serious blood clotting or bleeding complications. Given that promyelocytes do not express the glycophosphatidylinositol (GPI)-anchored protein CD16 and that deficient CD16 expression is a feature of some CD16 polymorphisms and paroxysmal nocturnal hemoglobinuria (PNH), we included the GPI anchor probe FLAER aerolysin in the APL flow cytometry probe panel. Initial tests showed that FLAER binding was absent in pathological promyelocytes from APL patients but was consistently detected with high intensity in healthy promyelocytes from control bone marrow. FLAER binding was studied in 71 hematologic malignancies. Appropriate control cells were obtained from 16 bone marrow samples from patients with idiopathic thrombocytopenic purpura and non-infiltrated non-Hodgkin’s lymphoma. Compared with the positive FLAER signal in promyelocytes from healthy bone marrow, malignant promyelocytes from APL patients showed weak or negative FLAER binding. The FLAER signal in APL promyelocytes was also lower than that in control myeloid progenitors and precursors from patients with other forms of acute myeloid leukemia (AML), B-cell acute lymphoblastic leukemia, or myelodysplastic syndrome. Minimal measurable disease studies performed in APL patients after treatment found normal promyelocyte expression when minimal measurable disease was negative and FLAER-negative promyelocytes when disease relapse was detected. The inclusion of FLAER in the flow cytometry diagnosis and follow-up of APL could be very helpful. Decreased FLAER binding was found in all cases of APL, confirmed by the detection of the PML-RARA fusion transcript and, to a lesser extent, in the other AMLs studied. This study also revealed FLAER differences in other acute leukemias and even between different precursors (myeloid and lymphoid) from healthy controls. However, the reason for FLAER’s non-binding to the malignant precursors of these leukemias remains unknown, and future studies should explore the possible relation with an immune escape phenomenon in these leukemias. Full article

The advent of recycling antibodies, leveraging pH-dependent antigen binding and optimized FcRn interaction, has advanced the field of antibody therapies, enabling extended durability and reduced dosages. Eculizumab (Soliris^®) demonstrated the efficacy of C5 inhibitors for paroxysmal nocturnal hemoglobinuria (PNH), while its derivative, ravulizumab (Ultomiris^®), recognized as a recycling antibody, extended the dosing intervals. However, limitations including intravenous administration and inefficacy in patients with the R885H single-nucleotide polymorphism (SNP) in C5 could necessitate alternative solutions. Crovalimab (PiaSky^®), a next-generation recycling antibody, overcomes these challenges with innovative charge engineering, achieving the enhanced cellular uptake of C5–crovalimab complexes and targeting a unique C5 epitope, allowing for efficacy regardless of the R885H SNP. This study highlights crovalimab’s distinctive molecular features, showing its eliminated binding to Fcγ receptors and C1q, alongside its optimized antigen binding characteristics. The impact of charge engineering was reconfirmed in mice, demonstrating faster C5 clearance than recycling antibodies. Notably, in the maintenance dosing regimen, crovalimab neutralizes approximately seven C5 molecules per antibody on average. Furthermore, its design also reduces the viscosity to facilitate high-concentration formulations suitable for subcutaneous delivery. Consequently, crovalimab offers a four-weekly subcutaneous injection regimen for PNH, marking a substantial improvement in treatment convenience and potentially transforming patients’ quality of life. Full article

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease characterized by complement-mediated hemolysis. OPERA is the first US longitudinal real-world study on C3 inhibitor therapy, known as pegcetacoplan. Methods: OPERA enrolled US patients with PNH, age ≥18, who were prescribed pegcetacoplan, and data were collected from routine care. Hemoglobin was reported by patients during regular follow-up (censored from transfusions). The Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue (0–52 score) and Patient-Reported Outcomes Measurement Information System scale for Cognitive Function Abilities (PROMIS-CF; 23.27–67.09 t-score) were completed electronically (low score = negative outcome). Patients self-reported incidence of healthcare resource utilization (HCRU). Results: By January 2024, 70 patients (mean age 44.6 years; 57.1% female) reported up to 9 months of pegcetacoplan treatment, with a median [IQR] follow-up of 6.6 [3.8] months. The latest reported hemoglobin levels improved by a mean (SD) of 2.6 (1.9) g/dL from baseline. At 3, 6 and 9 months, patients reported clinically meaningful improvements (≥5 points) in FACIT-F (53.3–69.0%) and (≥2 points) PROMIS-CF (46.7–55.2%). Patients reported a <10% incidence rate per person month of all HCRU events. Conclusions: This first longitudinal real-world US study indicates a positive trend in Hb, fatigue, and cognition with limited HCRU during pegcetacoplan treatment in adults with PNH. Full article

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and potentially life-threatening hematologic disorder caused by a somatic mutation in a relevant portion of hematopoietic stem cells. Mutation of the phosphatidylinositol glycan biosynthesis class A (PIGA) gene prevents the expression of cell-surface proteins, including the complement regulatory proteins CD55 and CD59. With decreased or a lack of CD55 and CD59 expression on their membranes, PNH red blood cells become susceptible to complement-mediated hemolysis (symptoms of which include anemia, dysphagia, abdominal pain, and fatigue), leading to thrombosis. State-of-the-art PNH treatments act by inhibiting the dysregulated complement at distinct points in the activation pathway: late at the C5 level (C5 inhibitors, eculizumab, ravulizumab, and crovalimab), centrally at the C3 level (C3/C3b inhibitors and pegcetacoplan), and early at the initiation and amplification of the alternative pathway (factor B inhibitor, iptacopan; factor D inhibitor, danicopan). Through their differing mechanisms of action, these treatments elicit varying profiles of disease control and offer valuable insights into the molecular underpinnings of PNH. This narrative review provides an overview of the mechanisms of action of the six complement inhibitors currently approved for PNH, with a focus on the C3/C3b-targeted therapy, pegcetacoplan. Full article