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Sixteen patients with paroxysmal nocturnal hemoglobinuria (PNH) from five European centers have been submitted to chromosome analysis. All of them had a normal bone marrow karyotype. The associations between some chromosomally abnormal cases reported in the literature and "typical" PNH or PNH phenomenon during the course of other hematological disorders are discussed.
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder of unknown frequency. In its classic form, PNH is characterized by hemolysis accompanied by nocturnal hemoglobinuria. The clinical course is unpredictable and may vary from severe hemolysis and recurrent venous thrombosis to latent periods with milder symptoms. We report a 15-year-old girl with hemolytic episodes, abdominal pain, and passage of dark urine. Hemoglobinuria was demonstrated by a "blood"-positive dipstick test in the absence of red blood cells in the urinary sediment. The diagnosis of PNH was confirmed by flow cytometry.
Paroxysmal nocturnal hemoglobinuria is a disorder characterized by the lack of membrane proteins affixed to the membrane by an anchor dependent upon phosphatidyl inositol, suggesting that some acquired abnormality in the metabolism of this class of proteins is basic to the disease. Most of the clinical symptoms can be explained by the lack of these proteins. However, much work is needed to understand completely the relationship of the biochemical facts and the clinical syndrome.
Occasionally it is difficult to differentiate paroxysmal nocturnal hemoglobinuria (PNH) from idiopathic aplastic anemia in patients who present with pancytopenia and an aplastic bone marrow. Patients with PNH may not have an abnormal acid hemolysis test, and patients with aplastic anemia may present with evidence of abnormal sucrose lysis, acid hemolysis, and antibody-mediated complement hemolysis. Demonstration of a population of red blood cells which are highly susceptible to antibody-mediated complement lysis makes a diagnosis of PNH probable. Donor red blood cell survival studies, which distinguish intracorpuscular from extracorpuscular hemolytic disorders, permit differentiation of the two disorders.
Venous thrombembolism is a major complication of paroxysmal nocturnal hemoglobinuria (PNH). Often, veins of atypical localization are afflicted, resulting in cerebral, mesenteric, or hepatic venous thrombosis. We present a patient who received an orthotopic liver graft for chronic Budd-Chiari syndrome in 1988. PNH was the only thrombophilic predisposition identified in this patient. After transplantation, he repeatedly suffered from hemorrhage. Subsequently, the patient discontinued prophylactic anticoagulation nearly 10 years after transplantation. Within 6 months Budd-Chiari syndrome recurred, but stabilized after anticoagulation therapy with low-molecular-weight heparin was reinstituted. The patient is clinically stable 14 years after receiving the liver graft. Eleven cases of relapsing Budd-Chiari syndrome have been reported in the literature. Of these, four patients suffered from PNH. All patients transplanted for PNH-associated Budd-Chiari syndrome in these reports suffered from either major bleeding or thrombosis. In conclusion, patients afflicted with PNH appear to be at high risk of incurring complications after liver transplantation.
The affected E of two patients with paroxysmal nocturnal hemoglobinuria (PNH) were enriched by lysing the unaffected, normal E with anti-human decay-accelerating factor (DAF) and guinea pig serum. The membranes of the unlysed, DAF-deficient cells (PNH-E) were dissolved and examined by SDS-PAGE and immunoblotting using an antiserum to homologous restriction factor (HRF). Whereas the 65 kD complement regulatory protein was readily detectable in the normal controls, it was completely lacking in both samples of PNH-E membranes. Functional studies likewise indicated the absence of HRF activity from PNH-E. When radiolabeled, isolated HRF protein was offered to PNH-E, it became firmly attached to the cell. Approximately 1,000 molecules of HRF per cell reduced the characteristic susceptibility of these cells to reactive lysis by C5b-9 to nearly normal levels. The results suggest that HRF, which is known to control the action of C8 and C9 on normal human E membranes, is deficient in PNH, as well as acetylcholinesterase and DAF.
Forty cases of paroxysmal nocturnal hemoglobinuria (PNH) were studied from 1978 to 1988. Thirty patients were male and 10 were female. Their ages ranged from 15 to 58 years with a median of 32 years. Symptoms related to anemia (85%) and dark colored urine (45%) were the most frequent clinical manifestations. Seven patients (17.5%) had a previous history of aplastic anemia. The interval between the diagnosis of aplastic anemia and PNH ranged from 11 months to 26 years. All the patients had anemia with varying combinations of cytopenia. In 36 patients, bone marrow examinations were performed, and 32 were hypercellular, one normocellular and 3 hypocellular. Documented thrombosis was noted in 3 patients, involving the intra-abdominal, cerebral and renal veins, respectively. The patient with intra-abdominal venous thrombosis subsequently died of E. coli septicemia. The remaining two patients achieved complete recovery. All 40 patients were treated with corticosteroids and/or anabolic agents, 32 (80%) patients improved and 4 (10%) achieved normal hemoglobin levels. Our studies demonstrate that there is a male predominance in Chinese PNH patients and the incidence of thrombotic complications is much lower than that reported by Western countries.
BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematologic disorder characterized by hemoglobinuria, thrombosis, infection, and a tendency toward bone marrow aplasia. Onset usually occurs in adulthood. Few children and adolescents with PNH have been described, and data on diagnosis, clinical course, and survival in young patients are unavailable. METHODS: We retrospectively reviewed clinical and laboratory data on all patients 21 years old or younger in whom PNH had been diagnosed at Duke University Medical Center from 1966 to 1991. RESULTS: Medical records and clinical follow-up data were available for 26 young patients. Although 50 percent of adult patients present with hemoglobinuria, only four of our patients (15 percent) presented with this feature. In contrast, 15 of our patients (58 percent) had moderate or severe bone marrow failure at presentation, as compared with about 25 percent of adults in cases from the literature; all 26 patients eventually had evidence of bone marrow dysfunction. Eight patients (31 percent) have died, with a median survival of 13.5 years since their initial symptoms. CONCLUSIONS: Children and adolescents with PNH have a greater prevalence of bone marrow failure than do adults with this disorder, and their morbidity and mortality are high. Bone marrow transplantation should be considered for selected young patients with PNH.
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hemolytic anemia characterized by the increased sensitivity of red cells to complement, leading to intravascular hemolysis and hemoglobinuria. Other clinical features are cytopenias caused by bone marrow failure and an increased risk of thrombosis. If unrecognized and not treated appropriately, PNH is often associated with a substantial morbidity and mortality. PNH is caused by the expansion of a hematopoietic progenitor cell that caries a somatic mutation in the X-linked phosphatidylinositol glycan complementation group A (PIGA) gene. The PIGA gene encodes a protein essential in the biosynthesis of glycosylphosphatidylinositol (GPI)-anchor molecules. A proportion of blood cells from patients with PNH is therefore deficient in all GPI-linked surface proteins. Considerable progress in the field of PNH research in the last 7 years has resulted from the cloning of the PIGA gene. The purpose of the current article is to describe the structure and function of the PIGA gene, to summarize the lessons learned from the analysis of PIGA gene mutations, to review the impact of mouse models on our current understanding of the human disease, and to discuss the possible pathogenesis of PNH. In addition, we will outline novel approaches to PNH diagnosis, research, and therapy that became available thanks to the cloning of the PIGA gene.
Paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes lack complement regulatory membrane proteins and are susceptible to complement. Although the critical role of complement in intravascular hemolysis in PNH is accepted, the precise mechanism of complement activation in vivo is unknown. Accordingly, in a PNH patient who was suffering from a hemolytic precipitation soon after a common cold-like upper respiratory infection, we analyzed the erythrocytes with lectins and by flow cytometry to detect membrane alteration that lead to complement activation. The lectin reactivity of erythrocytes showed the expression of cryptantigen Th. The patient serum at the time of the hemolysis induced the expression of Th on erythrocytes from PNH patients and from healthy volunteers in vitro, whereas neither the patient serum after recovery from the hemolysis nor blood type-matched control serum from healthy donor showed this activity. Moreover, autologous serum selectively hemolyzed Th+ PNH erythrocytes, but not Th- PNH erythrocytes, or Th+ control erythrocytes. Hemolysis was not observed either in complement-inactivated serum or in blood type-matched cord blood serum, which lacks natural antibodies to cryptantigens. These findings indicate that the immunoreaction of infection-induced Th with natural antibody on PNH erythrocytes is a trigger of the complement activation, leading to intravascular hemolysis.
The observation that type III erythrocytes of paroxysmal nocturnal hemoglobinuria (PNH) are susceptible to hemolysis initiated by activated cobra venom factor complexes (CoFBb), whereas normal erythrocytes are resistant, implies that the PNH III cells are deficient in a membrane constituent that regulates this process. To isolate the inhibitory factor from normal erythrocytes, membrane proteins were first extracted with butanol and then subjected to sequential anion exchange, hydroxylapatite, and hydrophobic chromatography. Analysis by SDS-PAGE and silver stain of the inhibitory fractions showed a single band corresponding to a protein with an apparent Mr of 18 kD. PNH erythrocytes were incubated with incremental concentrations of the radiolabeled protein and then washed. In a dose-dependent fashion, the protein incorporated into the cell membrane and inhibited CoFBb-initiated lysis. This protein inhibitor functioned by restricting the assembly of the membrane attack complex at the level of C7 and C8 incorporation. By using a monospecific antibody to block the function of the inhibitor, it was shown that normal erythrocytes are rendered susceptible to CoFBb-initiated hemolysis. Analysis by Western blot of membrane proteins revealed that PNH III erythrocytes are deficient in the 18-kD protein. By virtue of its molecular weight and inhibitory activity, the 18-kD protein appears to be discrete from other previously described erythrocyte membrane proteins that regulate complement. These studies also indicate that the susceptibility of PNH III erythrocytes to reactive lysis is causally related to a deficiency of the 18-kD membrane inhibitor.
Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic disorder characterized by complement-mediated hemolytic anemia, pancytopenia, and venous thrombosis. These clinical manifestations arise from an underlying molecular defect of bone marrow stem cells. Specifically, somatic mutations in the phosphatidylinositol glycan class A gene result in the ability of blood cells to anchor complement-regulatory proteins (CD59 and DAF) to the cell surface via glycosyl phosphatidylinositol (GPI). In an attempt to circumvent the functional defect in PNH cells, a recombinant transmembrane form of CD59 (CD59-TM) was analyzed for the ability to regulate complement activity. Balb/3T3 stable transfectants expressing similar levels of either CD59-TM or native CD59 (CD59-GPI) were equally protected against human complement-mediated membrane damage. Treatment of these cells with phosphatidylinositol-specific phospholipase C failed to release CD59-TM from the cell surface. Retroviral transduction of GPI-anchoring deficient mouse L cells with CD59-TM resulted in surface expression of the protein and rendered these cells resistant to human complement-mediated membrane damage. Conversely, L cells transduced with CD59-GPI failed to express this protein on the cell surface. A GPI-anchoring deficient complement-sensitive B-cell line derived from a PNH patient was successfully transduced with CD59-TM, resulting in surface expression of the protein. The PNH B cells expressing CD59-TM were protected against classical complement-mediated membrane damage by human serum. Taken together, these data establish that a functional recombinant transmembrane form of CD59 can be expressed on the surface of GPI-anchoring deficient PNH cells and suggest that retroviral gene therapy with this molecule could provide a treatment for PNH patients.
Paroxysmal nocturnal hemoglobinuria (PNH) is a disease that affects not only red cells, but other blood cells as well. The common defect is supposed to be an acquired deficiency of glycosyl-phosphatidylinositol (GPI)-anchored membrane proteins, which may be present already at the hematopoietic stem cell level. Recently, a panel of monoclonal antibodies (MoAbs) has become available directed against various GPI-linked membrane proteins. This makes it possible to study various cell lineages for the deficiency of such proteins in PNH in more detail. Using cytofluorography, we could show that the granulocytes of 20 different PNH patients miss not only GPI-linked FcRIII (CD16 antigen), but also three other GPI-linked proteins, ie, CD24 antigen, CD67 antigen and a granulocyte-specific 50 to 80 Kd antigen. The affected granulocytes were not only neutrophils but also eosinophils, as was found in a more detailed analysis of three patients. Moreover, in all 10 PNH patients tested, the monocytes were found to be deficient for the GPI-linked CD14 antigen, and we found with CD24 and CD55 (DAF) antibodies that lymphocytes may be involved as well. However, abnormal B and T lymphocytes were detected only in a subset of patients (2 of 10 tested). The uniform deficiency of GPI-linked proteins of granulocytes allows the introduction of a new diagnostic cytofluorometric assay for PNH with MoAbs against GPI-linked granulocytic antigens. This test was positive in all PNH patients studied and not in a group of 40 control patients or 50 normal donors, with the exception of three of 16 aplastic anemia (AA) patients. In the three AA patients, subpopulations (10% to 20%) of PNH granulocytes could be detected, whereas these patients had a negative acidified serum (Ham) test. This indicates that the new test is more sensitive than the Ham test and allows the early diagnosis of PNH in AA. An advantage of the neutrophil assay is that, in contrast to the Ham test, it is not influenced by recent red-cell transfusions. Moreover, it is possible to quantify the number of affected cells by single cell analysis.
Danazol was administered to two patients with paroxysmal nocturnal hemoglobinuria (PNH) with a dramatic effect on the hematological findings. The patients, 31- and 41-year-old females, were initially diagnosed as having aplastic anemia, and were initially treated with anabolic steroid and immunosuppressive therapy, respectively. Sugar water and Ham tests turned positive at the start of danazol therapy in the former patient and after two months in the latter patient. This drug produced a dramatic improvement in the hemoglobin level and the platelet count and showed few side effects in the patients. A possible mechanism of action of danazol for PNH is briefly discussed.
During the past two decades, we have had the opportunity to study a large number of patients with the rare hemolytic anemia, paroxysmal nocturnal hemoglobinuria. Sixteen surgical procedures have been performed upon ten patients with paroxysmal nocturnal hemoglobinuria. From this experience, we have developed certain recommendations for preoperative evaluation and preparation, intraoperative management and post-operative care. Any proposed surgical procedure for a patient with paroxysmal nocturnal hemoglobinuria should be closely managed by a team consisting of a surgeon, hematologist and anesthesiologist. In the preoperative evaluation, particular attention should be paid to the hematologic, renal and hepatic status. Transfusion requirements, whether precipitated by hemolytic episodes or surgical blood loss, should be met with either washed or perviously frozen erythrocytes, with consideration of the use of dextran for volume replacement. Dextran is the treatment of choice for thrombotic epidsodes. Close attention should be given to avoiding hypoxia and dehydration. Anesthetic agents which may activate complement or may be hepatotoxic are to be avoided.
Ex vivo expanded human bone marrow CD34(+)CD59(+) cells from patients with paroxysmal nocturnal hemoglobinuria (PNH) were transplanted into BALB/c mice in order to investigate their proliferation ability and reconstruction of hemopoiesis, and to lay the groundwork for clinical ABMT/APBSCT in PNH patients. CD34(+)CD59(+) cells were selected from the bone marrow mononuclear cells in PNH patients by using immunomagnetic positive double sorting. Sublethally irradiated BALB/c mice were transplanted with CD34(+)CD59(+) cells enriched from bone narrow of PNH patients. The results showed that human CD45(+) cells were detected in the bone marrow, spleen and peripheral blood of the nude mice by flow cytometry and DNA analysis at 6 weeks post-transplant. Blood routine indicators of nude mice were found to recover to some extent, but did not fully recover. It is concluded that ex vivo expanded bone marrow CD34(+)CD59(+) cells from patients with paroxysmal nocturnal hemoglobinuria could keep their biological characteristics and ability to reconstruct hemopoiesis in irradiated BALB/c mice.
UNLABELLED: Because women with paroxysmal nocturnal hemoglobinuria (PNH) are especially vulnerable to thromboembolic phenomena, pregnancy is a time of increased risk for both mother and fetus. However, pregnancies in affected women are rare; only case reports and small studies have been reported so far. We present the case of a 20-year-old woman with PNH who, while undergoing medical tests in preparation for a bone marrow transplant, was discovered to be pregnant. We also review the obstetric literature on pregnancy complicated by PNH, which indicates that both maternal and fetal mortality is exceptionally high (11.6% and 7.2%) with the major cause of maternal mortality being thromboembolism. Major maternal complications are more frequent postpartum (30.2%) than antepartum or intrapartum (16.3%). TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to recall that paroxysmal nocturnal hemoglobinuria (PNH) during pregnancy increases adverse events for both the mother and the fetus, state that maternal and fetal mortality are both high, and explain that the major complications occur in the postpartum period.
We have characterized the erythrocytes, granulocytes, and platelets of 54 patients with paroxysmal nocturnal hemoglobinuria (PNH) with antibodies to glycosylphosphatidylinositol-anchored proteins (anti-CD55, anti-CD59, and anti-CD16) and flow cytometry to establish the usefulness of this technique in the diagnosis of this disorder. All patients demonstrated either completely (PNH III) or partially (PNH II) deficient red cells and granulocytes. Anti-CD59 best demonstrated PNH II red cells, which were present in 50% of the patients. The proportion of abnormal granulocytes was usually greater than the proportion of abnormal red cells; 37% of the patients had >80% abnormal granulocytes. Anti-CD55 did not delineate the erythrocyte populations as well as did anti-CD59. Either anti-CD55 or anti-CD59 could be used equally well to analyze granulocytes; anti-CD16 did not demonstrate cells of partial deficiency. Platelets could not be used for detailed analysis as the normal and abnormal populations were not well distinguished. Flow cytometry of erythrocytes using anti-CD59 or of granulocytes using either anti-CD55 or anti-CD59 provides the most accurate technique for the diagnosis of paroxysmal nocturnal hemoglobinuria; it is clearly more specific, more quantitative, and more sensitive than the tests for PNH that depend upon hemolysis by complement (the acidified serum lysis [Ham] test, the sucrose lysis test, and the complement lysis sensitivity [CLS] test).