Pathophysiology, diagnosis, and treatment of paroxysmal nocturnal hemoglobinuria: a review

Classic paroxysmal nocturnal haemoglobinuria presenting with intestinal malabsorption syndrome, acute abdomen and acute kidney injury

A male patient in his 30s presented with complaints of acute abdominal pain, black stools and red-coloured urine. CT revealed thrombi in the splenic and left renal veins, leading to infarctions. An endoscopy displayed scalloping of the duodenal folds, indicative of intestinal malabsorption syndrome (IMS). Histopathological examination confirmed IMS. Due to the presence of intravascular haemolysis, haemoglobinuria and thrombotic complications, paroxysmal nocturnal haemoglobinuria (PNH) was suspected and subsequently confirmed by flow cytometry. Thus, a diagnosis of classic PNH with IMS and thrombotic complications was established. This unique case highlights the coexistence of PNH and IMS, resembling the complement hyperactivation, angiopathic thrombosis and protein-losing enteropathy disease, suggesting potential shared pathophysiology.

Burden of illness in Japanese patients with paroxysmal nocturnal hemoglobinuria receiving C5 inhibitors

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening blood disorder characterized by hemolysis and resulting in anemia and fatigue. Current therapies for PNH in Japan rely on complement inhibitors targeting the C5 component of the complement. However, the disease burden of Japanese patients with PNH treated with C5 inhibitors (C5i) remains unclear. To investigate this topic, we conducted a cross-sectional survey study that included 59 Japanese patients with PNH treated with C5i. Although many participants received C5i for 1 year or longer, the mean hemoglobin (Hb) level was 10.2 g/dL. Fatigue and shortness of breath were the most common symptoms at the time of diagnosis and survey. In addition, patients with Hb levels ≥ 10.5 g/dL also reported fatigue, depression and reduced quality of life, albeit to a lesser extent. These results suggest that a substantial burden of illness remains in patients with C5i-treated PNH, likely resulting in low quality of life and effects of symptoms on daily life. This study contributes to understanding the unmet needs of the current therapies for PNH, highlighting the need for novel therapeutics.

Progress in the Management of Pregnancy with Paroxysmal Nocturnal Hemoglobinuria: A Review

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired complement-mediated hemolytic disease characterized by intravascular hemolysis, thrombosis, smooth muscle dystonia, and so on. Thrombosis is the principal cause of death in PNH patients. During the perinatal period, pregnant PNH patients have increased morbidity and mortality with a heightened risk of complications, including significant preterm birth. The management of pregnancy complicated by PNH is difficult. Therefore, early diagnosis, standardized treatment protocols, and improving perinatal outcomes are crucial. However, there is a lack of consensus on treating patients with PNH during pregnancy. This article reviews 32 studies of pregnancy affected by PNH, focusing on the clinical presentation, diagnosis, and treatment strategies of PNH, to provide guidance for obstetricians on how to handle pregnant patients with PNH, and to offer academic support for the management of PNH patients. We found that Eculizumab has become the primary choice for treating PNH, effectively controlling intravascular hemolysis and reducing the frequency of blood transfusions necessary to stabilize the condition, with no severe threat to the safety of the mother and fetus.

Candida krusei pneumonia in graft-versus-host disease after allogeneic hematopoietic stem cell transplant for paroxysmal nocturnal hemoglobinuria: a case report

Introduction and importance

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder caused by a somatic mutation of PIGA (phosphatidylinositol glycan anchor biosynthesis, class A) gene that leads to the destruction of blood cells. Allogeneic haematopoietic stem cell transplant (HSCT) is a treatment option for PHN, but it can cause graft-versus-host disease (GVHD). Long-term immunosuppression as a treatment of GVHD increases the risk for invasive fungal infections such as Candida krusei pneumonia.

Case presentation

We present the case of a 22-year-old male with C. krusei pneumonia in a known case of chronic GVHD following HSCT for PNH undergoing long-term immunosuppressive therapy. The patient presented with progressive shortness of breath, productive cough, palpitations, and difficulty swallowing. On examination, he had skin rashes and oral lesions, along with signs of severe malnutrition. Diagnosis was made on the basis of radiological imaging and fungal culture.

Discussion

The combination of PNH, GVHD, and HSCT created an immunocompromised state, making the patient susceptible to opportunistic infections, including fungal pneumonia. Early recognition of this condition is challenging due to its non-specific symptoms and potential overlap with other post-transplant complications. Timely diagnosis and appropriate treatment, including antifungal therapy and immunosuppression management, are crucial for optimising patient outcomes.

Conclusion

This case highlights the importance of early recognition and timely treatment of fungal infections in patients with severe conditions such as GVHD following HSCT for PNH. Timely treatment with appropriate antifungals is necessary for optimal outcomes. Additionally, more research with long-term follow-up and monitoring is necessary to address the necessary knowledge gaps in this field.

Hemosiderin induced acute kidney injury requiring hemodialysis in patients with paroxysmal nocturnal hemoglobinuria: A case report

RATIONALE

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematopoietic stem cell disease with features of hemolytic anemia, thrombosis, and bone marrow failure. Due to intravascular hemolysis and hemoglobinuria, renal dysfunction is often accompanied in PNH patients.

PATIENT CONCERNS

A 25-year old woman presenting gross hematuria after coronavirus disease 2019 infection was admitted to our medical center. She had mild nausea and headache. She was diagnosed with iron deficiency anemia few years ago and had no other underlying disease. Her laboratory findings showed acute kidney injury (AKI) and severe anemia, with evidences of hemolysis.

DIAGNOSIS

Renal biopsy was done to determine the cause of renal failure and the result was acute tubular necrosis with deposition of golden pigments, hemosiderin. With pathologic result and laboratory finding of hemolysis, we did flow cytometry for PNH, and the patient was finally diagnosed with PNH.

INTERVENTIONS

With AKI and oliguria, the patient started to take hemodialysis.

OUTCOMES

After taking 5 sessions of hemodialysis, the patient's renal function was recovered from AKI. With diagnosis of PNH, the patient is now being treated with complement C5 inhibitor.

LESSONS

This challenging case tells us that we should consider the first manifestation of PNH as a cause of severe AKI requiring hemodialysis in a patient with anemia and evidence of hemolysis.

Severe hemolytic exacerbations of Chinese PNH patients infected SARS-CoV-2 Omicron

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by hemolytic anemia, bone marrow failure, thrombophilia. COVID-19, caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with many variants including Omicron.

METHODS

This study collected demographic and clinical data of 20 PNH patients with SARS-CoV-2 Omicron infection.

RESULTS

They all were with high disease activity, and LDH level exceeded any documented since the diagnosis of PNH, and those reported in the literature for previously stable treatment with complement inhibitors. D-dimer level elevated in 10 patients. 2 patients developed mild pulmonary artery hypertension. Glomerular filtration rate declined in 5 patients. 1 patient developed acute renal failure and underwent hemodialysis. Anemia and hemolysis were improved in 5 patients treated with eculizumab.

CONCLUSIONS

Hemolytic exacerbation of PNH with COVID-19 is severe and eculizumab may be an effective treatment.

Relationship of paroxysmal nocturnal hemoglobinuria (PNH) granulocyte clone size to disease burden and risk of major vascular events in untreated patients: results from the International PNH Registry

Paroxysmal nocturnal hemoglobinuria (PNH) is caused by acquired gene mutations resulting in deficiency of glycosylphosphatidylinositol (GPI)-anchored complement regulatory proteins on the surface of blood cells, leading to terminal complement-mediated intravascular hemolysis and increased risk of major adverse vascular events (MAVEs). Using data from the International PNH Registry, this study investigated the relationship between the proportion of GPI-deficient granulocytes at PNH onset and (1) the risk for MAVEs (including thrombotic events [TEs]) and (2) the following parameters at last follow-up: high disease activity (HDA); lactate dehydrogenase (LDH) ratio; fatigue; abdominal pain; and rates of overall MAVEs and TEs. A total of 2813 patients untreated at enrollment were included and stratified by clone size at PNH disease onset (baseline). At last follow-up, higher proportion of GPI-deficient granulocytes (≤ 5% vs. > 30% clone size) at baseline was associated with significantly increased HDA incidence (14% vs. 77%), mean LDH ratio (1.3 vs. 4.7 × upper limit of normal), and rates of MAVEs 1.5 vs. 2.9 per 100 person-years) and TEs (0.9 vs. 2.0 per 100 person-years). Fatigue was evident in 71 to 76% of patients regardless of clone size. Abdominal pain was more frequently reported with clone size > 30%. A larger clone size at baseline appears to indicate a greater disease burden and risk of TEs and MAVEs and may inform decision making among physicians managing PNH patients at risk of experiencing TEs or other MAVEs. ClinicalTrials.gov ID: NCT01374360.

The Effect of Respiratory Viral Infections on Breakthrough Hemolysis in Patients with Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by hemolysis and thrombosis and is associated with significant morbidity and mortality. Although complement inhibitors have significantly changed the outcomes in PNH patients, breakthrough hemolysis (BTH) may still occur as a response to stress factors such as pregnancy, surgery, and infections. Despite the well-described association between bacterial infections and hemolysis in PNH patients, little is known about the effect of respiratory viruses on triggering hemolytic episodes. This is the first study, to our knowledge, addressing this question. We retrospectively analyzed 34 patients with PNH disease between 2016 and 2018, who were on eculizumab treatment and who presented with respiratory symptoms and were subsequently tested for 10 respiratory viruses (influenza A, influenza B, parainfluenza, respiratory syncytial virus, adenovirus, rhinovirus, and human metapneumovirus). NTS+ patients had higher inflammatory markers, with the majority requiring antibiotics. Acute hemolysis, along with a significant drop in hemoglobin, was noted in the NTS+ group, with three of them requiring a top-up transfusion and two requiring an extra dose of eculizumab. Furthermore, the time from the last eculizumab dose was longer in the NTS+ patients who had BTH, than those who did not. Our data indicate that respiratory virus infections pose a significant risk for BTH in PNH patients on complement inhibitor treatment, underlining the need for regular screening and close monitoring of patients with respiratory symptoms. Furthermore, it implies a higher risk for patients who are not established on complement inhibitors, suggesting the necessity for greater vigilance in these patients.

Mapping the EORTC QLQ-C30 onto the EQ-5D-5L index for patients with paroxysmal nocturnal hemoglobinuria in France

Aim: To map patient-level data collected on the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC) QLQ-C30 to EQ-5D-5L data for estimating health-state utilities in patients with paroxysmal nocturnal hemoglobinuria (PNH). Materials & methods: European cross-sectional PNH patient survey data populated regression models mapping EORTC QLQ-C30 domains (covariates: sex and baseline age) to utilities calculated with the EQ-5D-5L French value set. A genetic algorithm allowed selection of the best-fitting between a set of models with and without interaction terms. We validated the selected algorithm using EQ-5D-5L utilities converted from EORTC QLQ-C30 data collected in the PEGASUS phase III, randomized controlled trial of pegcetacoplan versus eculizumab in adults with PNH. Results: Selected through the genetic algorithm, the ordinary least squares model without interactions provided highly stable results across study visits (mean [±SD] utilities 0.58 [±0.42] to 0.89 [±0.10]), and showed the best predictive validity. Conclusion: The new PNH EQ-5D-5L direct mapping developed using a genetic algorithm enabled calculation of reliable health-state utility data required for cost-utility analysis in health technology assessments supporting treatments of PNH.

The burden of illness of patients with paroxysmal nocturnal haemoglobinuria receiving C5 inhibitors: clinical outcomes and medical encounters from the patient perspective

OBJECTIVES

To assess the clinical and healthcare resource burden among C5 inhibitor (C5i)-treated patients with paroxysmal nocturnal haemoglobinuria (PNH), using patient-reported data.

METHODS

This web-based, cross-sectional survey (01FEB2021-31MAR2021) of adults with PNH treated with eculizumab (France, Germany, UK) or ravulizumab (Germany) included: patient characteristics; treatment patterns/dosage; haematological outcomes (haemoglobin [Hb] levels, transfusions, thrombotic events, breakthrough haemolysis); and medical encounters. Treatment and Hb-level subgroup differences were assessed with statistical significance tests.

RESULTS

Among 71 patients, 98.6% were C5i-treated for ≥3 months. The majority (with reported Hb levels) had levels ≤12.0 g/dL (85.7%; n = 54/63). The mean Hb level was 10.2 g/dL (standard deviation [SD]: 2.0; median 10.0 g/dL). Treatment with above label-recommended doses was reported by 30.4% (eculizumab) and 5.3% (ravulizumab) of patients. Within the past 12 months among patients treated with C5i for ≥1 year: 24.1% had ≥1 transfusion; 3.2% had ≥1 thrombosis; and 28.6% had ≥1 breakthrough haemolysis. Among all patients, 26.8% and 31.0% reported emergency department/room [ER] and inpatient visits, respectively. Mean annual, per-patient all-cause medical encounters were: 0.5 (ER); 1.9 (inpatient); and overall outpatient visits ranged by setting from 2.0 to 6.4. Most encounters were PNH-related, with means of 0.4 (ER); 1.8 (inpatient); and 1.6-5.4 (outpatient). Primary haematological and medical encounter outcomes were similar between treatment as well as Hb-level subgroups, with almost no statistically significant differences.

CONCLUSIONS

Despite at least 3 months of C5i treatment, high proportions of patients with PNH reported low haemoglobin levels and required transfusions and hospitalizations, which suggests remaining unmet needs.

Thrombosis in Pregnant Women with Hemolytic Anemia

Hemolytic anemias are a group of uncommon disorders affecting both genders, frequently occurring at the reproductive age. While a link between hemolysis and hypercoagulability has been suggested based on the elucidation of certain involved pathophysiological mechanisms, the extent of thrombotic risk in pregnant women with hemolytic anemia remains debatable. Due to the paucity of pregnancy-related data, risk assessment of gestations in women with hemolytic anemia is complicated. This review will highlight the latest advances in the diagnosis and management of these challenging disorders in pregnancy.

Pancytopenia in a Case of Aplastic Anaemia/Paroxysmal Nocturnal Haemoglobinuria Unmasked by SARS-CoV-2 Infection: A Case Report

During an acute SARS-CoV-2 infection, a diagnosis of Aplastic Anaemia associated with Paroxysmal Nocturnal Haemoglobinuria (AA/PNH) was made in a 78-year-old woman who had presented to the emergency department with severe pancytopenia. It is possible that she had subclinical AA/PNH that was unmasked during the acute COVID-19 infection, but we can also suspect a direct role of the virus in the pathogenesis of the disease, or we can hypothesize that COVID-19 infection changed the phosphatidylinositol glycan class A (PIGA) gene pathway.

Pulmonary embolism in a patient with eltrombopag-treated aplastic anaemia and paroxysmal nocturnal haemoglobinuria clone during COVID-19 pneumonia

Thrombosis in patients with thrombocytopenia has several risk factors, both disease-related and treatment-associated. Recently, COVID-19 infection was recognized as an additional risk factor, further complicating the delicate balance between thrombosis and bleeding in these patients. Here we describe the case of a patient with aplastic anaemia on eltrombopag who developed pulmonary embolism during COVID-19 pneumonia, despite receiving oral anticoagulation with edoxaban. Notably, he was also carrying a large paroxysmal nocturnal haemoglobinuria clone, although without evidence of haemolysis. The presented case recapitulates some of the open questions in thrombotic risk management of cytopenic patients, such as the management of thrombopoietin receptor agonists and the choice of anticoagulation in PNH, while also accounting for the additional thrombotic risk linked to COVID-19.

The cost-effectiveness, of pegcetacoplan compared with ravulizumab for the treatment of paroxysmal nocturnal hemoglobinuria, in a UK setting

Aim: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder characterized by hemolytic anemia, bone marrow failure and thrombosis. We evaluated, the cost-effectiveness of pegcetacoplan, a novel proximal C3 inhibitor, versus ravulizumab in patients with PNH and hemoglobin levels <10.5 g/dl despite eculizumab treatment in the UK healthcare and social services setting. Materials & methods: A Markov cohort framework model, based on the data from the pivotal trial of pegcetacoplan (PEGASUS/NCT03500549), evaluated lifetime costs and outcomes. Patients transitioned through 3 PNH hemoglobin level/red blood cell transfusion health states. Results: Pegcetacoplan provides lower lifetime costs/greater quality-adjusted life years (£6,409,166/14.694QALYs, respectively) versus ravulizumab (£6,660,676/12.942QALYs). Conclusion: Pegcetacoplan is associated with enhanced anemia control, greater QALYs and reduced healthcare costs versus ravulizumab in the UK healthcare and social services setting.

The Burden of Illness of Patients With Paroxysmal Nocturnal Haemoglobinuria Receiving C5 Inhibitors in France, Germany and the United Kingdom: Patient-reported Insights on Symptoms and Quality of Life

OBJECTIVES

To assess the clinical, humanistic, and economic burden of paroxysmal nocturnal haemoglobinuria (PNH) among C5 inhibitor (C5i)-treated patients with PNH METHODS: This was a web-based, cross-sectional survey (01FEB2021-31MAR2021) of adults with PNH treated with eculizumab (France, Germany, UK) or ravulizumab (Germany). Self-reported outcomes included: patient characteristics; patient-reported symptoms; and standardized patient-reported outcomes (e.g., Functional Assessment of Chronic Illness Therapy [FACIT]-Fatigue, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 [EORTC QLQ-C30]).

RESULTS

Among 71 included patients, 98.6% were C5i-treated for ≥3 months (88.7% ≥12 months); among those with self-reported haemoglobin (Hb) levels (n=63), most (85.7%) were anaemic (defined as ≤12.0 g/dL). Fatigue was the most common symptom at both diagnosis (73.2%) and survey time (63.4%); there were no statistically significant differences in symptom prevalence between treatment subgroups (eculizumab versus ravulizumab). Total FACIT-Fatigue and EORTC QLQ-C30 scores were substantially lower than European general population references, but there were no statistically significant differences between treatment subgroups. Hb level subgroups (<10.5 g/dL versus ≥10.5 g/dL) followed similar trends for all measures, with few significant subgroup differences.

CONCLUSIONS

Results suggest that there remains a considerable burden and unmet need among C5i-treated patients with PNH that requires improved therapies.

The spectrum of paroxysmal nocturnal hemoglobinuria clinical presentation in a Brazilian single referral center

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder caused by the expansion of a hematopoietic clone harboring a somatic genetic variant in the PIG-A gene translating into a wide spectrum of clinical and laboratory changes, from intravascular hemolysis, thrombosis, and bone marrow failure to subclinical presentation. In this study, we retrospectively analyzed 87 consecutive cases (39 women; median follow-up, 18 months; range, 0–151 months) in whom a PNH clone was detected by flow cytometry between 2006 and 2019 seen at a single Brazilian referral center. The median age at diagnosis was 29 years (range, 8 to 83 years); 29 patients (33%) were initially classified as PNH/bone marrow failure, 13 (15%) as classic PNH, and 45 (52%) as subclinical PNH. The median overall survival (OS) of the entire cohort was not reached during follow-up, without significant differences between groups. At diagnosis, the median PNH clone size was 2.8% (range, 0 to 65%) in erythrocytes and 5.4% (range, 0 to 80%) in neutrophils. Fourteen patients experienced clone expansion during follow-up; in other 14 patients the clone disappeared, and in 18 patients it remained stable throughout the follow-up. A subclinical PNH clone was detected in three telomeropathy patients at diagnosis, but it was persistent and confirmed by DNA sequencing in only one case. In conclusion, PNH presentation was variable, and most patients had subclinical disease or associated with marrow failure and did not require specific anticomplement therapy. Clone size was stable or even disappeared in most cases.

Long-term follow-up of patients with paroxysmal nocturnal hemoglobinuria treated with eculizumab: post-marketing surveillance in Japan

All Japanese patients with paroxysmal nocturnal hemoglobinuria (PNH) treated with eculizumab were enrolled in post-marketing surveillance (PMS) between June 2010 and August 2019 to assess the long-term effectiveness and safety of eculizumab. The reduction in intravascular hemolysis, the change in hemoglobin (Hb) level, and the change in renal function were assessed to determine the effectiveness of eculizumab. The types and frequencies of adverse events (AEs) were assessed to determine its safety. A total of 632 patients were enrolled and the median treatment duration was 3.6 years. Treatment with eculizumab significantly reduced lactate dehydrogenase (LDH) levels and significantly increased Hb levels. These changes were maintained for up to 5 years of treatment. An estimated glomerular filtration rate ≥ 60 ml/min/1.73 m² and higher LDH level at baseline were associated with increases in Hb levels during eculizumab treatment. The overall incidence of any AE was 69.92/100 patient-years. Hemolysis was the most common AE (6.43/100 patient-years). The incidence of infection-related AEs was 20.57/100 patient-years, and included meningococcal infection in three patients (0.12/100 patient-years). This long-term follow-up of patients with PNH demonstrated the sustained effectiveness of eculizumab and supports its well-established safety profile.

Management of Vascular Thrombosis in Patients with Thrombocytopenia

Platelets play critical roles in hemostasis and thrombosis. While low platelet counts increase the risk of bleeding, antithrombotic drugs, including anticoagulants and antiplatelet agents, are used to treat thromboembolic events. Thus, the management of thrombosis in patients with low platelet counts is challenging with hardly any evidence available to guide treatment. Recognition of the underlying cause of thrombocytopenia is essential for assessing the bleeding risk and tailoring therapeutic options. A typical clinical scenario is the occurrence of venous thromboembolism (VTE) in cancer patients experiencing transient thrombocytopenia during myelosuppressive chemotherapy. In such patients, the severity of thrombocytopenia, thrombus burden, clinical symptoms, and the timing of VTE relative to thrombocytopenia must be considered. In clinical practice, distinct hematological disorders characterized by low platelet counts and a thrombogenic state require specific diagnostics and treatment. These include the antiphospholipid syndrome, heparin-induced thrombocytopenia (HIT) and (spontaneous) HIT syndromes, disseminated intravascular coagulation, and paroxysmal nocturnal hemoglobinuria.

[Brain infarction and cerebral venous thrombosis in paroxysmal nocturnal hemoglobinuria: case report]

A 65-year-old woman with a six-year history of paroxysmal nocturnal hemoglobinuria (PNH) was admitted due to weakness in the right leg following a seven-day history of fever and upper respiratory infection. MRI revealed several high-intensity areas in bilateral frontal lobe cortices and the left cerebellum on diffusion-weighted imaging, and signal hypointensity along the course of the cortical vein in the left frontal lobe on T₂*-weighted imaging. We diagnosed cerebral venous thrombosis and brain infarction, and commenced heparin infusion. She developed right-sided dens hemiparesis on hospital day 6, when brain CT showed subcortical hemorrhage in the left frontal lobe. Despite eculizumab administration and decompressive craniectomy for hematoma, she died on hospital day 26. Thrombosis in PNH has been recognized as a life-threating complication, and intensive treatment including emergent administration of eculizumab is warranted if this situation arises.

Posthepatectomy jaundice induced by paroxysmal nocturnal hemoglobinuria: A case report

BACKGROUND

Jaundice is a major manifestation of posthepatectomy liver failure, a feared complication after hepatic resection. Herein, we report a case of posthepatectomy jaundice that was not caused by liver failure but by paroxysmal nocturnal hemoglobinuria (PNH)-induced hemolysis.

CASE SUMMARY

A 56-year-old woman underwent right hepatectomy and biliary tract exploration surgery due to hepatic duct stones. Prior to surgery, the patient was mildly anemic. The direct antiglobulin test was negative. A bone marrow biopsy showed mild histiocyte hyperplasia. After surgery, the patient suffered a progressive increase in serum bilirubin. Meanwhile, the patient developed hemolytic symptoms after blood transfusion. She was ultimately diagnosed with PNH. PNH is a rare bone marrow failure disorder that manifests as complement-dependent intravascular hemolysis with varying severity. After steroid treatment, the patient’s jaundice gradually decreased, and the patient was discharged on the 35^th postoperative day.

CONCLUSION

PNH-induced hemolysis is a rare cause of posthepatectomy jaundice. It should be suspected in patients having posthepatectomy hyperbilirubinemia without other signs of liver failure. Steroid therapy can be considered for the treatment of PNH in such cases.

Different clinical courses with the same findings: two cases of paroxysmal nocturnal hemoglobinuria presenting with thrombocytopenia

Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal stem cell disease that manifests with chronic intravascular hemolysis, thrombosis, and bone marrow failure. Various degrees of cytopenias accompany the disease. Although laboratory and clinical findings are similar, the disease may show different courses and require different treatments. Herein, we report two different courses of PNH with similar clinical and laboratory findings.

Cost-Utility Analysis of Eculizumab for the Treatment of Paroxysmal Nocturnal Hemoglobinuria from the Perspective of the Brazilian Public Health System

OBJECTIVE

To perform a first cost-utility analysis of eculizumab for the treatment of paroxysmal nocturnal hemoglobinuria from the perspective of the Brazilian Unified Health System.

METHODS

A Markov decision model was developed for 35-year-old patients with symptomatic paroxysmal nocturnal hemoglobinuria. We used a cycle length of one month and a time horizon of 20 years. The effectiveness measure was the quality-adjusted life year (QALY). Data were extracted from clinical trials, historical cohorts, and Unified Health System databases. Resource use and costs were estimated from the perspective of the Unified Health System. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

The estimated gain in effectiveness with the use of eculizumab was 1.08 QALY through the incremental cost of R$10,959,375.95. The incremental cost-effectiveness ratio was R$10,139,542.84 per QALY, being 331.92 times greater than the Brazilian gross domestic product per capita. In the deterministic sensitivity analysis, the parameters related to the utilities of health states were associated with greater impact in the model. The results of the probabilistic sensitivity analysis with 1000 simulations evidence that 100% of the simulations were not considered cost-effective with the arbitrated willingness to pay R$30,548.40 and R$91,645.20 per QALY.

CONCLUSIONS

The gain in effectiveness with the use of eculizumab was modest, associated with an unjustifiable incremental cost. Therefore, eculizumab is not a cost-effective drug compared with the current standard of care in the treatment of paroxysmal nocturnal hemoglobinuria from the Brazilian Unified Health System perspective.

COVID19 infection in a patient with paroxysmal nocturnal hemoglobinuria: A case report

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired, life-threatening hemopoietic stem cell disorder characterized by the triad of hemolytic anemia, thrombosis, and impaired bone marrow function. Evidence suggests that severe outcomes in COVID19 infection are attributed to the excessive activation of the complement cascade leading to acute lung injury and associated is with an increased prothrombotic state.

PATIENT CONCERNS

A 27-year-old Caucasian man with PNH presented to the Emergency Department of our hospital with acute onset shortness of breath, cough and blood in urine.

DIAGNOSIS

The patient was diagnosed with acute hemolytic exacerbation of PNH complicated with moderate COVID19 pneumonia.

OUTCOMES

The patient was initiated with an anticoagulant unfractionated heparin, dexamethasone, and cefuroxime injection. His symptoms quickly resolved, and he was discharged after 5 days.

CONCLUSION

The complement system activation is a critical component in the sequalae of COVID19 infection. Evidence suggests that severe outcomes in COVID19 infection are attributed to the excessive activation of the complement cascade leading to acute lung injury and associated is with an increased prothrombotic state. Notably, C5a concentration was noted to be higher in patients with COVID19 infection. The use of complement inhibitors to attenuate immune mediated damage in COVID19 nevertheless represents a very interesting theoretical approach. However, careful consideration as to which patients may benefit will be required and the outcome of clinical trials needed.

Clinical characteristics and therapeutic outcomes of paroxysmal nocturnal hemoglobinuria patients in Turkey: a multicenter experience

The aim of this study is to collect paroxysmal nocturnal hemoglobinuria (PNH) patient data from hematology centers all over Turkey in order to identify clinical features and management of PNH patients. Patients with PNH were evaluated by a retrospective review of medical records from 19 different institutions around Turkey. Patient demographics, medical history, laboratory findings, and PNH-specific information, including symptoms at the diagnosis, complications, erythrocyte, and granulocyte clone size, treatment, and causes of death were recorded. Sixty patients (28 males, 32 females) were identified. The median age was 33 (range; 17-77) years. Forty-six patients were diagnosed as classic PNH and 14 as secondary PNH. Fatigue and abdominal pain were the most frequent presenting symptoms. After eculizumab became available in Turkey, most of the patients (n = 31/46, 67.4%) were switched to eculizumab. Three patients with classic PNH underwent stem cell transplantation. The median survival time was 42 (range; 7-183 months) months. This study is the first and most comprehensive review of PNH cases in Turkey. It provided us useful information to find out the differences between our patients and literature, which may help us understand the disease.

Difficult Cases of Paroxysmal Nocturnal Hemoglobinuria: Diagnosis and Therapeutic Novelties

Paroxysmal nocturnal hemoglobinuria (PNH) is an intriguing disease that can pose many difficulties to physicians, as well as to hematologists, who are unfamiliar with it. Research regarding its pathophysiologic, diagnostic, and therapeutic aspects is still ongoing. In the last ten years, new flow cytometry techniques with high sensitivity enabled us to detect PNH clones as small as <1% of a patient's hematopoiesis, resulting in increasing incidence but more difficult data interpretation. Particularly, the clinical significance of small PNH clones in patients with bone marrow failures, including aplastic anemia and myelodysplastic syndromes, as well as in uncommon associations, such as myeloproliferative disorders, is still largely unknown. Besides current treatment with the anti-C5 eculizumab, which reduced PNH-related morbidity and mortality, new complement inhibitors will likely fulfill unmet clinical needs in terms of patients' quality of life and better response rates (i.e., responses in subjects with C5 polymorphisms; reduction of extravascular hemolysis and breakthrough hemolysis episodes). Still, unanswered questions remain for these agents regarding their use in mono- or combination therapy, when to treat, and which drug is the best for which patient. Lastly, long-term safety needs to be assessed in real-life studies. In this review, we describe some clinical vignettes illustrating practical aspects of PNH diagnosis and management; moreover, we discuss recent advances in PNH diagnostic and therapeutic approaches.

Movement Disorders and Hematologic Diseases

Background

Movement disorders can be associated with or caused by hematological abnormalities. The objective of this review is to highlight features that will aid in the clinician's recognition and treatment of these disorders.

Methods

MESH terms relevant to movement disorders and hematologic diseases were searched to identify conditions included in this narrative, educational review.

Results

Several conditions were identified, and they were organized by hematologic categories to include red blood cell abnormalities, white blood cell abnormalities, disorders of clotting and bleeding, hematologic malignancies, and others.

Conclusions

This review will increase providers' understanding of disorders that include movement disorders and hematologic abnormalities. Basic hematologic laboratories can aid in assessment of these disorders, to include complete blood count/hemogram and peripheral blood smear. Recognition is key, especially in the setting of underlying malignancy, vitamin deficiency, or other disorder in which treatment is available.

Bone Marrow Failure Syndromes, Overlapping Diseases with a Common Cytokine Signature

Bone marrow failure (BMF) syndromes are a heterogenous group of non-malignant hematologic diseases characterized by single- or multi-lineage cytopenia(s) with either inherited or acquired pathogenesis. Aberrant T or B cells or innate immune responses are variously involved in the pathophysiology of BMF, and hematological improvement after standard immunosuppressive or anti-complement therapies is the main indirect evidence of the central role of the immune system in BMF development. As part of this immune derangement, pro-inflammatory cytokines play an important role in shaping the immune responses and in sustaining inflammation during marrow failure. In this review, we summarize current knowledge of cytokine signatures in BMF syndromes.

One-year outcomes from a phase 3 randomized trial of ravulizumab in adults with paroxysmal nocturnal hemoglobinuria who received prior eculizumab

Ravulizumab every 8 weeks showed non‐inferiority to eculizumab every 2 weeks in a 26‐week, phase 3, randomized controlled trial in adults with paroxysmal nocturnal hemoglobinuria (PNH) who were clinically stable on eculizumab (NCT03056040). We report results from the first 26 weeks of the extension period in which patients continued ravulizumab (n = 96) or switched from eculizumab to ravulizumab (n = 95). At week 52, mean (SD) lactate dehydrogenase levels increased 8.8% (29%) with ravulizumab‐ravulizumab and 5.8% (27%) with eculizumab‐ravulizumab from primary evaluation period baseline. During the extension period, four patients (ravulizumab‐ravulizumab, n = 3; eculizumab‐ravulizumab, n = 1) experienced breakthrough hemolysis, but none associated with serum free C5 ≥ 0.5 μg/mL. Mean Functional Assessment of Chronic Illness Therapy (FACIT)‐Fatigue scores remained stable through week 52. During the extension period, proportions of patients avoiding transfusion remained stable (ravulizumab‐ravulizumab, 86.5%; eculizumab‐ravulizumab, 83.2%); 81.2% and 81.1%, respectively, had stabilized hemoglobin. All patients maintained serum free C5 levels < 0.5 μg/mL. Adverse events were generally similar between groups, and rates were lower in the extension period. Adults with PNH on stable eculizumab therapy who received ravulizumab over 52 weeks experienced durable efficacy, with consistent efficacy in patients who received eculizumab during the primary evaluation period and then switched to ravulizumab. Ravulizumab was well tolerated.

Differences in the Hemolytic Behavior of Two Isomers in Ophiopogon japonicus In Vitro and In Vivo and Their Risk Warnings

Ophiopogonin D (OPD) and Ophiopogonin D′ (OPD′) are two bioactive ingredients in Ophiopogon japonicus. Previously published studies have often focused on the therapeutic effects related to OPD's antioxidant capacity but underestimated the cytotoxicity-related side effects of OPD′, which may result in unpredictable risks. In this study, we reported another side effect of OPD′, hemolysis, and what was unexpected was that this side effect also appeared with OPD. Although hemolysis effects for saponins are familiar to researchers, the hemolytic behavior of OPD or OPD′ and the interactions between these two isomers are unique. Therefore, we investigated the effects of OPD and OPD′ alone or in combination on the hemolytic behavior in vitro and in vivo and adopted chemical compatibility and proteomics methods to explain the potential mechanism. Meanwhile, to explain the drug-drug interactions (DDIs), molecular modeling was applied to explore the possible common targets. In this study, we reported that OPD′ caused hemolysis both in vitro and in vivo, while OPD only caused hemolysis in vivo. We clarified the differences and DDIs in the hemolytic behavior of the two isomers. An analysis of the underlying mechanism governing this phenomenon showed that hemolysis caused by OPD or OPD′ was related to the destruction of the redox balance of erythrocytes. In vivo, in addition to the redox imbalance, the proteomics data demonstrated that lipid metabolic disorders and mitochondrial energy metabolism are extensively involved by hemolysis. We provided a comprehensive description of the hemolysis of two isomers in Ophiopogon japonicus, and risk warnings related to hemolysis were presented. Our research also provided a positive reference for the development and further research of such bioactive components.

Upper gastrointestinal ischemia as a rare complication of paroxysmal nocturnal hemoglobinuria

When patients with PNH present with abdominal symptoms, thrombosis-induced gastrointestinal injury should be considered; computed tomography and esophagogastroduodenoscopy may help make the diagnosis of this potentially serious complication.

Dental infection associated with exuberant gingival necrosis in a patient with paroxysmal nocturnal hemoglobinuria: A case report

Paroxysmal nocturnal hemoglobinuria (PNH) is a hematological disorder that affects hematopoietic stem cells. An association with other hematological diseases, such as hemolytic anemia and neutropenia, is observed with a high occurrence of aplastic anemia. The aim of the present study is to report a case of dental infection in a patient with PNH exhibiting exuberant gingival involvement. A 45-year-old male patient sought the Federal University of Ceara reporting severe toothache associated with tooth 24. Clinical examination revealed that the tooth was associated with an apparent fistula and a yellowish lesion with smooth surface located in the palate. The patient had interrupted the medication to control PNH. Blood transfusion was requested due to deficient hematological parameters. Tooth extraction and excisional biopsy were performed under antibiotic coverage. In the postoperative period, low-level laser therapy (LLLT) was performed. Histopathological examination revealed connective tissue showing extensive necrotic areas, accumulation of basophilic material, numerous cyst-like cavities, and degenerated cells. Histopathological findings were compatible with the initial clinical diagnosis of gingival necrosis. The patient evolved with febrile neutropenia, requiring hospitalization for 1 month. Improvement in the overall health was observed after the administration of antibiotics, eculizumab, and weekly LLLT at the biopsy site.

Paroxysmal nocturnal hemoglobinuria: current treatments and unmet needs

The current standard of care for paroxysmal nocturnal hemoglobinuria (PNH) are the C5 inhibitors eculizumab and ravulizumab, both monoclonal antibodies designed to target the complement protein C5, thereby preventing its cleavage and the formation of the terminal attack complex. C5 inhibitors have yielded substantial improvements in the treatment of PNH and changed the mortality and morbidity, as well as health-related quality of life of patients with the disease. These treatments target underlying intravascular hemolysis; however, they do not address extravascular hemolysis, resulting in incomplete response and remaining symptoms in some patients. Therefore, despite treatment with a C5 inhibitor, some patients still experience anemia with associated fatigue, transfusion needs, and impaired health-related quality of life. DISCLOSURES: This research was developed under a research contract between RTI Health Solutions and Apellis Pharmaceuticals and was funded by Apellis Pharmaceuticals. Bektas, Copley-Merriman, and Khan are employees of RTI Health Solutions. Sarda is an employee of Apellis Pharmaceuticals. Shammo consults for Apellis Pharmaceuticals.

Presence of paroxysmal nocturnal hemoglobinuria in patients with idiopathic portal vein thrombosis: a single-center study

Background/aim

Paroxysmal nocturnal hemoglobinuria (PNH) is a very rare clonal hematopoietic stem cell disease characterized by chronic hemolytic anemia and thrombosis. We report data from a study of the occurrence of PNH among patients with idiopathic portal vein thrombosis (PVT).

Materials and methods

Patients who were followed up with the diagnosis of idiopathic PVT were enrolled into this study. Those with laboratory and/or imaging evidence of any local or systemic factor that could lead to PVT were excluded. PNH clone was examined in all patients using established FLAER methodology.

Results

A total of 112 patients (42 males and 70 females), none of them had a markedly PNH clone, but 4 patients (3.6%) with confirmed tests two times had small PNH clones (size between 3.02% and 4.62%). The median ages of PNH clone (-) and PNH clone (+) patients were 42 (range; 24–59) vs 39 (range; 36–42) years, respectively. The median hemoglobin concentration, platelet count and leukocyte count were lower in the PNH clone (+) group than the PNH clone (-) group. Anemia, thrombocytopenia, and leukopenia were detected in all PNH clone (+) patients. In addition, the PNH clone positivity size in monocytes was higher than erythrocytes in all of 4 patients.

Conclusions

PNH should be considered during differential diagnosis among patients with idiopathic PVT. Small PNH clones can be detected in PVT patients that we cannot clearly determine its relationship with PVT. We need furthermore studies to explore the potential role of this finding.

Patients with paroxysmal nocturnal hemoglobinuria demonstrate a prothrombotic clotting phenotype which is improved by complement inhibition with eculizumab

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder, characterized by complement-mediated intravascular hemolysis and thrombosis. The increased incidence of PNH-driven thrombosis is still poorly understood, but unlike other thrombotic disorders, is thought to largely occur through complement-mediated mechanisms. Treatment with a C5 inhibitor, eculizumab, has been shown to significantly reduce the number of thromboembolic events in these patients. Based on previously described links between changes in fibrin clot structure and thrombosis in other disorders, our aim was to investigate clot structure as a possible mechanism of thrombosis in patients with PNH and the anti-thrombotic effects of eculizumab treatment on clot structure. Clot structure, fibrinogen levels and thrombin generation were examined in plasma samples from 82 patients from the National PNH Service in Leeds, UK. Untreated PNH patients were found to have increased levels of fibrinogen and thrombin generation, with subsequent prothrombotic changes in clot structure. No link was found between increasing disease severity and fibrinogen levels, thrombin generation, clot formation or structure. However, eculizumab treated patients showed decreased fibrinogen levels, thrombin generation and clot density, with increasing time spent on treatment augmenting these antithrombotic effects. These data suggest that PNH patients have a prothrombotic clot phenotype due to increased fibrinogen levels and thrombin generation, and that the antithrombotic effects of eculizumab are, in-part, due to reductions in fibrinogen and thrombin generation with downstream effects on clot structure.

Paroxysmal nocturnal hemoglobinuria: Test to monitor the action of eculizumab treatment

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is caused by a somatic mutation in the PIG-A gene, which encodes for glycosylphosphatidylinositol, a phospholipid membrane that anchors proteins like CD55 and CD59. These proteins are inhibitors of the complement-mediated lysis. PNH is diagnosed by flow cytometry, and treatment with eculizumab improves the life quality of patients with severe clinical compromise. The aim of this work was to evaluate a hemolytic test that allows monitoring the blockade of the alternative complement pathway caused by eculizumab (herein MET test).

METHODS

There were analyzed a total of 163 serum samples from nine patients with PNH under treatment with eculizumab and ten healthy volunteers like controls. The patients were evaluated for 6 months. The MET test consisted in incubating red blood cells from patients (RBC_PNH ) with either acidified serum from healthy volunteers and from patients with PNH. The results can be (a) Positive, (b) Blockade profile, or (c) Negative.

RESULTS

Seven patients responded favorably to the eculizumab, and the test evidenced the blockade profile. The two remaining patients were nonresponders to the treatment, with a positive MET test. In these patients, the dose was increased. One responded favorably with a blockade profile, and the other continued to be nonresponder.

CONCLUSIONS

The MET test proved to be a useful tool to monitor the blockade of complement by eculizumab.

Laboratory studies for paroxysmal nocturnal hemoglobinuria, with emphasis on flow cytometry

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal hematopoietic stem cell disorder caused by somatic mutations in the PIG-A gene, leading to the production of blood cells with absent or decreased expression of glycosylphosphatidylinositol-anchored proteins, including CD55 and CD59. Clinically, PNH is classified into three variants: classic (hemolytic), in the setting of another specified bone marrow disorder (such as aplastic anemia or myelodysplastic syndrome) and subclinical (asymptomatic). PNH testing is recommended for patients with intravascular hemolysis, acquired bone marrow failure syndromes and thrombosis with unusual features. Despite the availability of consensus guidelines for PNH diagnosis and monitoring, there are still discrepancies on how PNH tests are carried out, and these technical variations may lead to an incorrect diagnosis. Herein, we provide a brief historical overview of PNH, focusing on the laboratory tests available and on the current recommendations for PNH diagnosis and monitoring based in flow cytometry.

Thrombotic risk in paroxysmal nocturnal hemoglobinuria-like (PNH-like) phenotype

The complement system is an essential component of the innate immune defence that, if overly activated, may damage organs and tissues. For this reason, there is a fine complement regulatory system. The complement modulation system includes two proteins with important regulatory activity, CD55 or decay accelerating factor (DAF) and CD59 or membrane inhibitor of reactive lysis (MIRL).The paroxysmal nocturnal hemoglobinuria (PNH) is a clonal and non-neoplastic disease characterized by intravascular haemolysis, occurrence of thrombosis and bone marrow failure.In clinical practice, in opposition to PNH, a variety of pathological conditions have been observed with an acquired and non-genetic deficiency of the regulatory proteins CD55 and CD59. This abnormal, non-clonal, reduced expression of complement regulatory proteins configures what we may define as PNH-like phenotype.Similarly to PNH, even in the PNH-like phenotype diseases there has been a greater exposure to the mediated complement cellular lysis and, a likely increased risk of thromboembolic events.Therefore, the knowledge of the potential roles of the complement system becomes necessary for a deeper understanding of several pathological conditions and for an improved clinical management of the patients.

Analysis of clinical characteristics of 92 patients with paroxysmal nocturnal hemoglobinuria: A single institution experience in China

Objectives

We performed a retrospective analysis to investigate the clinical characteristics and therapeutic strategies of Chinese paroxysmal nocturnal hemoglobinuria (PNH) patients, and assessed the efficacy and safety of glucocorticoid in PNH patients.

Methods

The clinical data of 92 PNH cases in our hospital were analyzed, including clinical manifestation, laboratory examination, treatment efficacy, and survival.

Results

The main clinical manifestations of these patients included hemoglobinuria, anemia, fatigue, dyspnea, headache, abdominal pain, and erectile dysfunction. Glucocorticoid is still the first‐line treatment for PNH patients to control hemolytic attack, and the short‐term remission rate (12 months) is 79.01% (64/81). Meanwhile, the overall survival (OS) of 10 years after diagnosis was estimated as 70.77% (46/65). Moreover, Cox proportional risk model for multivariate analysis showed that the increase in LDH multiple, thrombosis complications, and complicated with bone marrow failure were the independent adverse prognostic factors affecting the survival of PNH patients.

Conclusion

Paroxysmal nocturnal hemoglobinuria patients in mainland China have various clinical features, while lower incidences of thrombosis and renal damage. Thrombosis and bone marrow failure are two complications with worse prognosis.

Acute myocardial infarction in a Chinese patient with paroxysmal nocturnal hemoglobinuria: A case report

RATIONALE

Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal hematopoietic stem cell disease. Patients with PNH often experience a high incidence (14%-40%) of thrombotic events, which are mainly venous and rarely arterial thrombotic events. Because it is very rare, delay in diagnosis is common in patients with PNH, imposing a remarkable impact on patient's management and prognosis.

PATIENT CONCERNS

We presented a 33-year-old female case with no medical history of any systemic illnesses who complained of approximately 1-month progressively worsening constant heartburn, and was also hospitalized twice due to acute myocardial infarction (AMI).

DIAGNOSES

In our case, AMI occurred twice, whereas there were no cardiovascular risk factors and abnormalities based on the angiography of the coronary artery. Flow cytometry analysis showed that 25% of CD55 and CD59 were lost on the surface of neutrophils, and 30% of CD55 and CD59 were lost on the surface of the blood cells. Thus, our diagnosis of this patient was AMI secondary to PNH.

INTERVENTIONS AND OUTCOMES

For the first myocardial infarction, local hospitals used thrombolytic therapy to alleviate symptoms. After the patient's second myocardial infarction was treated in our hospital, we adopted coronary interventional therapy. Considering the patient's situation, eculizumab was given for treatment. The patient was gradually restored to achieve stability, and the follow-up observation showed that there was no arterial thrombosis.

LESSONS

This case report aimed to provide a reliable reference for the rare cause of AMI. In addition, PNH should be highly taken into consideration in young patients who have a rare cause of AMI.

Successful treatment of noncirrhotic portal hypertension with eculizumab in paroxysmal nocturnal hemoglobinuria: A case report

BACKGROUND

Idiopathic non-cirrhotic portal hypertension (INCPH) is mainly associated with thrombophilia in Western countries. Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematologic disease that manifests with hemolytic anemia, thrombosis, and peripheral blood cytopenias. Portal and hepatic venous thrombosis were reported in PNH. A rare case of INCPH complicating PNH is described.

CASE SUMMARY

A 63-year old woman with a 2-year past medical history of PNH without treatment was admitted because of jaundice and refractory ascites requiring large volume paracentesis. Liver histology revealed portal venopathy with portal fibrosis and sclerosis, nodular regenerative hyperplasia, parenchymal ischemic changes, and focal sinusoidal and perivenular fibrosis without bridging fibrosis or cirrhosis, all indicative of INCPH. The flow cytometry confirmed PNH diagnosis and eculizumab treatment was initiated. Her condition was improved gradually, bilirubin was normalized 6 months following initiation of eculizumab, and 1 year later diuretics were stopped.

CONCLUSION

Eculizumab improved intravascular hemolysis and reversed clinical manifestations of INCPH in a patient with paroxysmal nocturnal hemoglobinuria.

Diagnosis and management of PNH: Review and recommendations from a Belgian expert panel

Despite its considerable morbidity and mortality, paroxysmal nocturnal haemoglobinuria (PNH) is still underdiagnosed. Patients with PNH can suffer from cardiovascular, gastrointestinal, neurological or haematological symptoms and refer to several specialists. The aim of this paper is to review the diagnosis and the management of PNH patients, with the primary focus on identifying high-risk groups. Additionally, the implementation and prognostic value of the defined high-risk groups will be commented on and the management of PNH patients is discussed from a Belgian perspective. Finally, based on the available data, recommendations are provided. Eculizumab is a potent C5 complement inhibitor and reduces intravascular haemolysis and thrombosis in PNH patients and improves their quality of life. As thrombosis is the main cause of death in PNH patients, identifying high-risk PNH patients in need of therapy is essential. Currently, novel complement inhibitors are in development and the first data seem promising. Another challenge in PNH is to identify new markers to assess the thrombotic risk to achieve a better risk-based prophylactic anti-thrombotic management. Finally, because of the low prevalence of the disease, PNH patients should be included in the prospective PNH registry, which will offer new insights on the natural course of the disease and the impact of treatment of PNH.