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.

COVID-19 induced mesenteric ischemia in a patient with ulcerative colitis and paroxysmal nocturnal haemoglobinuria despite thromboprophylaxis.

Inflammatory bowel disease and paroxysmal nocturnal hemoglobinuria (PNH) are both well-known prothrombotic states. However, ongoing thromboprophylaxis is usually effective in such conditions. We report an imbalance that was triggered by COVID-19 infection. There is evidence that COVID-19 infection leads to thrombosis of vessels. The thrombosis of mesenteric vessels can be multifocal and without respiratory symptoms and leads to devastating consequences like resection of large segments of the bowel and lifelong requirement of parenteral nutritional support. We report about a case of ulcerative colitis (in remission) and PNH where COVID-19 resulted in mesenteric ischemia.

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.

Hemolysis induced by SARS-CoV-2 mRNA vaccination in patients with paroxysmal nocturnal hemoglobinuria.

Autoimmune and complement-related hematological side effects have been observed with messenger ribonucleic acid (mRNA) vaccines. Here, we report the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-induced hemolysis in patients with paroxysmal nocturnal hemoglobinuria (PNH). We reviewed the medical records of seventeen patients with PNH visiting the University of Tsukuba Hospital who had received two doses of the SARS-CoV-2 mRNA vaccine between May 2021 and November 2021. Twelve patients were being treated with complement inhibitors. The median age of all patients was 62 years (range 29-89 years).; six were males and eleven were females. Fourteen patients received the BNT162b2 vaccine (Pfizer/BioNTech) and three received the mRNA-1273 vaccine (Moderna). The median percentages of PNH clones in erythrocytes and granulocytes were 37.61% (range 8.11-85.71%) and 59.73% (range 3.76-97.82%), respectively. Of the twelve patients receiving complement inhibitors, only one had a hemolytic reaction after vaccination, but it did not meet the definition of breakthrough hemolysis. By contrast, hemolytic attacks were observed in two of the five untreated patients with PNH, and one of them required a blood transfusion. Appropriate administration of complement inhibitors to patients with PNH may prevent hemolysis induced by SARS-CoV-2 mRNA vaccination.

COVID-19 Presented with Deep Vein Thrombosis in a Patient with Paroxysmal Nocturnal Haemoglobinuria.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, acquired clonal haematological disease characterized by complement-mediated haemolysis, bone marrow failure and venous thrombosis. Anticomplement therapy eculizumab improves survival and reduces complications. Severe acute respiratory distress syndrome corona virus 2 (SARS-CoV-2) disease 2019 (COVID-19) is associated with high incidence of both venous and arterial thrombosis in hospitalized patients with pneumonia. Deep venous thrombosis (DVT) as the presenting symptom of COVID-19 is a rare event. We describe a well-controlled PNH patient on eculizumab for more than 5 years who presented with DVT, while on warfarin, as the first sign of COVID-19. To our knowledge, this is the first described case of DVT in a PNH patient with COVID-19.

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.

Lip necrosis in a patient with paroxysmal nocturnal hemoglobinuria: Can it be triggered by COVID-19?

BACKGROUND: COVID-19 due to SARS-CoV-2 was first described in the city of Wuhan in China and spread around the world turning into a pandemic. COVID-19 can affect different organ systems, including the oral mucosa. AIMS: Although cutaneous involvement has been defined in association with COVID-19, the number of case reports about mucosal involvement by SARS-CoV-2 is limited. Hereby, we report a case of hemorrhagic necrosis on the lip in a patient with paroxysmal nocturnal hemoglobinuria (PNH) and COVID-19 infection and briefly discuss its possible mechanism. PATIENTS: The clinical features and causes of hemorrhagic necrosis on the lip in a woman are presented. RESULTS: In our patient, we think that PNH-associated dermal micro-occlusions caused extensive painful necrosis of the lip. Additionally, COVID-19-induced endothelial damage helped to develop exaggerated hemorrhagic necrosis. CONCLUSION: This current case presentation will contribute to the literature as another case with COVID-19 triggering mucosal involvement.

Mild Clinical Course of COVID-19 in 3 Patients Receiving Therapeutic Monoclonal Antibodies Targeting C5 Complement for Hematologic Disorders.

BACKGROUND Patients receiving immunosuppressive therapies might be more susceptible to COVID-19. Conversely, an exaggerated inflammatory response to the SARS-CoV-2 infection might be blunted by certain forms of immunosuppression, which could be protective. Indeed, there are data from animal models demonstrating that complement may be a part of the pathophysiology of coronavirus infections. There is also evidence from an autopsy series demonstrating complement deposition in the lungs of patients with COVID-19. This raises the question of whether patients on anti-complement therapy could be protected from COVID-19. CASE REPORT Case 1 is a 39-year-old woman with an approximately 20-year history of paroxysmal nocturnal hemoglobinuria (PNH), who had recently been switched from treatment with eculizumab to ravulizumab prior to SARS-CoV-2 infection. Case 2 is a 54-year-old woman with a cadaveric renal transplant for lupus nephritis, complicated by thrombotic microangiopathy, who was maintained on eculizumab, which she started several months before she developed the SARS-CoV-2 infection. Case 3 is a 60-year-old woman with a 14-year history of PNH, who had been treated with eculizumab since 2012, and was diagnosed with COVID-19 at the time of her scheduled infusion. All 3 patients had a relatively mild course of COVID-19. CONCLUSIONS We see no evidence of increased susceptibility to SARS-CoV-2 in these patients on anti-complement therapy, which might actually have accounted for the mild course of infection. The effect of anti-complement therapy on COVID-19 disease needs to be determined in clinical trials.

COVID-19: A collision of complement, coagulation and inflammatory pathways.

COVID-19 is frequently accompanied by a hypercoagulable inflammatory state with microangiopathic pulmonary changes that can precede the diffuse alveolar damage characteristic of typical acute respiratory distress syndrome (ARDS) seen in other severe pathogenic infections. Parallels with systemic inflammatory disorders such as atypical hemolytic uremic syndrome (aHUS) have implicated the complement pathway in the pathogenesis of COVID-19, and particularly the anaphylatoxins C3a and C5a released from cleavage of C3 and C5, respectively. C5a is a potent cell signalling protein that activates a cytokine storm-a hyper-inflammatory phenomenon-within hours of infection and the innate immune response. However, excess C5a can result in a pro-inflammatory environment orchestrated through a plethora of mechanisms that propagate lung injury, lymphocyte exhaustion, and an immune paresis. Furthermore, disruption of the homeostatic interactions between complement and extrinsic and intrinsic coagulation pathways contributes to a net pro-coagulant state in the microvasculature of critical organs. Fatal COVID-19 has been associated with a systemic inflammatory response accompanied by a pro-coagulant state and organ damage, particularly microvascular thrombi in the lungs and kidneys. Pathologic studies report strong evidence of complement activation. C5 blockade reduces inflammatory cytokines and their manifestations in animal studies, and has shown benefits in patients with aHUS, prompting investigation of this approach in the treatment of COVID-19. This review describes the role of the complement pathway and particularly C5a and its aberrations in highly pathogenic virus infections, and therefore its potential as a therapeutic target in COVID-19.