Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), has been demonstrated to be able to activate complement, making patients with deficiency in negative complement regulation, such as paroxysmal nocturnal hemoglobinuria (PNH), particularly vulnerable to complement-mediated cell damage. We report a case of a patient who presented with fatigue, facial swelling, and upper respiratory infection (URI) symptoms and was found to have COVID-19 with laboratory tests showing severe hemolysis and pancytopenia secondary to PNH.
Project description:Paroxysmal nocturnal hemoglobinuria (PNH) is a rare bone marrow failure disorder that manifests with hemolytic anemia, thrombosis, and peripheral blood cytopenias. The absence of two glycosylphosphatidylinositol (GPI)-anchored proteins, CD55 and CD59, leads to uncontrolled complement activation that accounts for hemolysis and other PNH manifestations. GPI anchor protein deficiency is almost always due to somatic mutations in phosphatidylinositol glycan class A (PIGA), a gene involved in the first step of GPI anchor biosynthesis; however, alternative mutations that cause PNH have recently been discovered. In addition, hypomorphic germ-line PIGA mutations that do not cause PNH have been shown to be responsible for a condition known as multiple congenital anomalies-hypotonia-seizures syndrome 2. Eculizumab, a first-in-class monoclonal antibody that inhibits terminal complement, is the treatment of choice for patients with severe manifestations of PNH. Bone marrow transplantation remains the only cure for PNH but should be reserved for patients with suboptimal response to eculizumab.
Project description:Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematologic disorder characterized by complement-mediated hemolysis. C5 inhibitors (eculizumab/ravulizumab) control intravascular hemolysis but do not prevent residual extravascular hemolysis. The newly approved complement inhibitor, pegcetacoplan, inhibits C3, upstream of C5, and has the potential to improve control of complement-mediated hemolysis. The PADDOCK and PALOMINO clinical trials assessed the safety and efficacy of pegcetacoplan in complement inhibitor-naïve adults (≥ 18 years) diagnosed with PNH. Patients in PADDOCK (phase 1b open-label, pilot trial) received daily subcutaneous pegcetacoplan (cohort 1: 180 mg up to day 28 [n = 3]; cohort 2: 270-360 mg up to day 365 [n = 20]). PALOMINO (phase 2a, open-label trial) used the same dosing protocol as PADDOCK cohort 2 (n = 4). Primary endpoints in both trials were mean change from baseline in hemoglobin, lactate dehydrogenase, haptoglobin, and the number and severity of treatment-emergent adverse events. Mean baseline hemoglobin levels were below the lower limit of normal in both trials (PADDOCK: 8.38 g/dL; PALOMINO: 7.73 g/dL; normal range: 11.90-18.00 g/dL), increased to within normal range by day 85, and were sustained through day 365 (PADDOCK: 12.14 g/dL; PALOMINO: 13.00 g/dL). In PADDOCK, 3 serious adverse events (SAE) led to study drug discontinuation, 1 of which was deemed likely related to pegcetacoplan and 1 SAE, not deemed related to study drug, led to death. No SAE led to discontinuation/death in PALOMINO. Pegcetacoplan was generally well tolerated and improved hematological parameters by controlling hemolysis, while also improving other clinical PNH indicators in both trials. These trials were registered at www.clinicaltrials.gov (NCT02588833 and NCT03593200).
Project description:Pregnancies in paroxysmal nocturnal hemoglobinuria (PNH) are associated with increased morbidity and mortality. Retrospective studies suggest that outcome has improved with the advent of the complement inhibitor eculizumab. To substantiate this assumption we analyzed the data from patients treated in our department since 2009. All patients were included in the International PNH registry and followed prospectively. We identified 16 pregnancies in 9 patients with classical PNH, and two pregnancies in two patients with aplastic anemia (AA)-PNH. In classical PNH, 13 pregnancies were supported by eculizumab. Breakthrough hemolysis occurred in six pregnancies, necessitating an increase in the biweekly eculizumab dose from 900 mg to 1,200-1,800 mg. Red blood cell transfusions were given in six and platelet transfusions in two pregnancies. A Budd-Chiari syndrome and cholecystitis complicated the course of two pregnancies. Four of 13 pregnancies supported by eculizumab ended in spontaneous abortion or stillbirth, and one was prematurely terminated because of fetal trisomy 21. None of the three pregnancies not supported by eculizumab had a successful outcome. Half the deliveries were preterm. None of the patients died, and, in all but one patient, the post-partum period was uneventful. Both pregnancies in patients with AA-PNH took a favorable course. Our results confirm low maternal mortality and frequent breakthrough hemolysis in pregnant PNH patients receiving eculizumab. Fetal mortality and the rate of preterm delivery were higher than reported previously, possibly related to the use of registry data that are likely to reduce the risk of publication and recall biases.
Project description:Clinical and hematological parameters in six cases of paroxysmal nocturnal hemoglobinuria (PNH) are presented. The mean delay in diagnosis after onset of symptoms was 3.7 years. Initial diagnoses considered were: (a) hematuria; (b) iron-deficiency; hemolytic; megaloblastic or refractory anemia and (c) myelodysplastic syndrome. Clinical features included; reddish urine (5/6), unexplained abdominal pain (4/6) and pallor (6/6). Laboratory investigations showed anemia (6/6), leucopenia (3/6), thrombocytopenia (3/6), unconjugated hyperbilirubinemia at some stage (6/6), and bone marrow erythroid hyperplasia (6/6). Complications encountered were (a) gall stones needing cholecystectomy, hemosiderosis and proximal tubular acidosis in 1 case, (b) disseminated tuberculosis in 1 case and (c) abortion with congestive cardiac failure in one. PNH may present with atypical features and tests for hemosiderinuria, sucrose lysis test and HAM's test are required to establish the diagnosis.
Project description:Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal blood disorder characterized by hemolysis and a high risk of thrombosis, that is due to a deficiency in several cell surface proteins that prevent complement activation. Its origin has been traced to a somatic mutation in the PIG-A gene within hematopoietic stem cells (HSC). However, to date the question of how this mutant clone expands in size to contribute significantly to hematopoiesis remains under debate. One hypothesis posits the existence of a selective advantage of PIG-A mutated cells due to an immune mediated attack on normal HSC, but the evidence supporting this hypothesis is inconclusive. An alternative (and simpler) explanation attributes clonal expansion to neutral drift, in which case selection neither favours nor inhibits expansion of PIG-A mutated HSC. Here we examine the implications of the neutral drift model by numerically evolving a Markov chain for the probabilities of all possible outcomes, and investigate the possible occurrence and evolution, within this framework, of multiple independently arising clones within the HSC pool. Predictions of the model agree well with the known incidence of the disease and average age at diagnosis. Notwithstanding the slight difference in clonal expansion rates between our results and those reported in the literature, our model results lead to a relative stability of clone size when averaging multiple cases, in accord with what has been observed in human trials. The probability of a patient harbouring a second clone in the HSC pool was found to be extremely low ([Formula: see text]). Thus our results suggest that in clinical cases of PNH where two independent clones of mutant cells are observed, only one of those is likely to have originated in the HSC pool.
Project description:Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening hematologic stem cell disorder characterized by hemoglobinuria, thrombosis, and tendency for bone marrow failure. The rare incidence of PNH in children, its nonspecific clinical presentation, and occasional absence of hemoglobinuria make the diagnosis challenging. We present a case of a 17-year-old boy who was hospitalized with a history of recurrent abdominal pain, fever, and dark-colored urine. Laboratory tests revealed anemia, thrombocytopenia, and elevated inflammatory markers. Urinalysis was positive for protein and red blood cells, too many to be counted. Complement studies were within normal limits. Abdominal computed tomography showed a segment of the small bowel with wall thickening and signs of possible microperforation. Exploratory laparotomy revealed necrosis of the small bowel, and histological evaluation was suggestive of an autoimmune process with small vessel vasculitis. Bone marrow biopsy showed hypocellular marrow with a decreased number of myeloid cells, normal number of megakaryocytes, and signs of erythroid hyperplasia. Flow cytometry detected deficiency of CD59 leading to the diagnosis of PNH. The patient was treated with eculizumab infusions resulting in significant improvement. This case highlights the need for high clinical suspicion for rare entities such as PNH in patients presenting without hemoglobinuria.