scholarly journals Aplastic anemia and paroxysmal nocturnal hemoglobinuria: search for a pathogenetic link

Blood ◽  
1995 ◽  
Vol 85 (5) ◽  
pp. 1354-1363 ◽  
Author(s):  
A Griscelli-Bennaceur ◽  
E Gluckman ◽  
ML Scrobohaci ◽  
P Jonveaux ◽  
T Vu ◽  
...  
Keyword(s):  
Protein Expression ◽  
Aplastic Anemia ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Antithrombin Iii ◽  
Clinical Symptoms ◽  
Flow Cytometric Analysis ◽  
Normal Subjects ◽  
Initial Study ◽  
Pnh Clone

The association of paroxysmal nocturnal hemoglobinuria (PNH) and aplastic anemia (AA) raises the yet unresolved questions as to whether these two disorders are different forms of the same disease. We compared two groups of patients with respect to cytogenetic features, glycosylphosphatidylinositol (GPI)-linked protein expression, protein C/protein S/thrombomodulin/antithrombin III activity, and PIG-A gene expression. The first group consisted of eight patients with PNH (defined as positive Ham and sucrose tests at diagnosis), and the second, 37 patients with AA. Twelve patients with AA later developed a PNH clone. Monoclonal antibodies used to study GPI-linked protein expression (CD14 [on monocytes], CD16 [on neutrophils], CD48 [on lymphocytes and monocytes], CD67 [on neutrophils and eosinophils], and, more recently, CD55, CD58, and CD59 [on erythrocytes]) were also tested on a cohort of 20 normal subjects and five patients with constitutional AA. Ham and sucrose tests were performed on the same day as flow- cytometric analysis. Six of 12 patients with AA, who secondarily developed a PNH clone, had clinical symptoms, while all eight patients with PNH had pancytopenia and/or thrombosis and/or hemolytic anemia. Cytogenetic features were normal in all but two patients. Proteins C and S, thrombomodulin, and antithrombin III levels were within the normal range in patients with PNH and in those with AA (with or without a PNH clone). In patients with PNH, CD16 and CD67 expression were deficient in 78% to 98% of the cells and CD14 in 76% to 100%. By comparison, a GPI-linked defect was detected in 13 patients with AA, affecting a mean of 32% and 33% of CD16/CD67 and CD14 cell populations, respectively. Two of three tested patients with PNH and 1 of 12 patients with AA had a defect in the CD48 lymphocyte population. In a follow-up study of our patient cohort, we used the GPI-linked molecules on granulocytes and monocytes investigated earlier and added the study of CD55, CD58, and CD59 on erythrocytes. Two patients with PNH and 14 with AA were studied for 6 to 13 months after the initial study. Among patients with AA, four in whom no GPI-anchoring defect was detected in the first study had no defect in follow-up studies of all blood-cell subsets (including erythrocytes). Analysis of granulocytes, monocytes, and erythrocytes was performed in 7 of 13 AA patients in whom affected monocytes and granulocytes were previously detected. A GPI-anchoring defect was detected on erythrocytes in five of six.(ABSTRACT TRUNCATED AT 400 WORDS)

Clinical Reflection of Immunophenotyping in Paroxysmal Nocturnal Hemoglobinuria: Experience of a Single Center

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5150-5150
Author(s):  
Ugur Sahin ◽  
Mustafa Merter ◽  
Pinar Ataca ◽  
Erden Atilla ◽  
Berna Atesagaoglu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Myelodysplastic Syndrome ◽  
Aplastic Anemia ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Treatment Modalities ◽  
Serum Lactate Dehydrogenase ◽  
Clone Size ◽  
Bone Marrow Disorders ◽  
Pnh Clone

Abstract Introduction: Flow cytometric assays (FCA), especially FLAER based methods, have become important recently in means of diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). In this retrospective study, we aimed to describe diagnostic features of PNH patients along with disease characteristics. Methods: FCA results of patients ordered for PNH diagnosis between November 2007 and July 2014 were retrospectively evaluated. FCA results were expressed as percentage of granulocytes and monocytes negative for CD55/59. The FLAER/CD24-CD14 assay has been available in our center since December 2011 and used for confirmation of FCA results since then. The distribution of erythrocyte types according to CD59 expression (type 1, 2 and 3) were also given in percentages. Results: FCA for PNH diagnosis was performed for a total of 175 patients. FLAER method was available in 136 of these assays (77.7%). A PNH clone was not detected in 136 (77.7%) of the FCAs. PNH clone free patients were diagnosed with unclassified anemia (n=34, 19.4%), other unclassified cytopenias (n=30, 17.2%), non-PNH hemolytic anemias (n=7, 4.0%), myelodysplastic syndrome (n=23, 13.1%), aplastic anemia (n=9, 5.1%), primary myelofibrosis (n=1, 0.6%), leukemia (n=7, 4.0%), lymphoma (n=3, 1.7%), thrombotic incidents (n=14, 8.0%), rheumatological disorders (n=4, 2.3%) and unknown diagnosis (n=4, 2.3%). A PNH clone was detected in 39 patients (22.3%). Of these, 27 (69.2%) constituted classical PNH and 12 (30.8%) PNH accompanying other bone marrow disorders. In the PNH clone positive group, the accompanying bone marrow disorders were aplastic anemia (n=9) and myelodysplastic syndrome (n=3). Median age at diagnosis was 31 (10-82) for classical PNH and 35 (18-77) for PNH accompanying other bone marrow disorders. Erythrocyte transfusion requirement was prominent in 48.7% (n=19) of the patients and thrombotic incidents occured in 20.5% (n=8). Leukemic transformation did not take place in any of the patients. In one patient with aplastic anemia, the FCA became positive for PNH clone within one year of follow-up. Among classical PNH patients, thrombosis was observed only among patients with a clone size of > 50%. Clone size (both for granulocyte and monocyte clones) correlated with corrected reticulocyte and serum lactate dehydrogenase levels (for granulocytes p=0.001 and p<0.001, for monocytes p=0.001 and p<0.001, respectively). Treatment modalities of the PNH clone positive patients included eculizumab (n=12, 30.8%), allogeneic stem cell transplantation (n=13, 33.3%) and none/other (CsA, steroids, ATG, danazol) (n=16, 41.0%). Conclusion: FCA is an important modality for the diagnosis and follow-up of PNH patients. Clone size might be used to assess the severity of the disease and the risk of thrombosis in classical PNH. In patients with PNH accompanying other bone marrow disorders clone sizes are generally small and complications seen in classical PNH are rare. However, aplastic anemia and myelodysplastic syndrome might evolve into PNH during the disease course, which is reflected as an increase in clone size. Thus, FCA might be used in selected patients with aplastic anemia and myelodysplastic syndrome, especially when treatment failure or unexpected complications are suspected. Disclosures No relevant conflicts of interest to declare.

scholarly journals Paroxysmal Nocturnal Hemoglobinuria Clones Are Infrequent in Hepatitis-Associated Aplastic Anemia at the Time of Diagnosis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5016-5016
Author(s):  
Wenrui Yang ◽  
Xin Zhao ◽  
Guangxin Peng ◽  
Li Zhang ◽  
Liping Jing ◽  
...  
Keyword(s):  
Aplastic Anemia ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Conflicts Of Interest ◽  
Bone Marrow Failure ◽  
Clonal Evolution ◽  
Extrinsic Factors ◽  
Clone Size ◽  
Hematopoietic Stem ◽  
Over Time ◽  
Pnh Clone

Aplastic anemia (AA) is an immune-mediated bone marrow failure, resulting in reduced number of hematopoietic stem and progenitor cells and pancytopenia. The presence of paroxysmal nocturnal hemoglobinuria (PNH) clone in AA usually suggests an immunopathogenesis in patients. However, when and how PNH clone emerge in AA is still unclear. Hepatitis associated aplastic anemia (HAAA) is a special variant of AA with a clear disease course and relatively explicit immune pathogenesis, thus serves as a good model to explore the emergence and expansion of PNH clone. To evaluate the frequency and clonal evolution of PNH clones in AA, we retrospectively analyzed the clinical data of 90 HAAA patients that were consecutively diagnosed between August 2006 and March 2018 in Blood Diseases Hospital, and we included 403 idiopathic AA (IAA) patients as control. PNH clones were detected in 8 HAAA patients (8.9%,8/90) at the time of diagnosis, compared to 18.1% (73/403) in IAA. Eight HAAA patients had PNH clone in granulocytes with a median clone size of 3.90% (1.09-12.33%), and 3 patients had PNH clone in erythrocytes (median 4.29%, range 2.99-10.8%). Only one HAAA patients (1/8, 12.5%) had a PNH clone larger than 10%, while 24 out of 73 IAA patients (32.9%) had larger PNH clones. Taken together, we observed a less frequent PNH clone with smaller clone size in HAAA patients, compared to that in IAAs. We next attempted to find out factors that associated with PNH clones. We first split patients with HAAA into two groups based on the length of disease history (≥3 mo and < 3mo). There were more patients carried PNH clone in HAAA with longer history (21.4%, 3/14) than patients with shorter history (6.6%, 5/76), in line with higher incidence of PNH clone in IAA patients who had longer disease history. Then we compared the PNH clone incidence between HAAA patients with higher absolute neutrophil counts (ANC, ≥0.2*109/L) and lower ANC (< 0.2*109/L). Interestingly, very few VSAA patients developed PNH clone (5%, 3/60), while 16.7% (5/30) of non-VSAA patients had PNH clone at diagnosis. We monitored the evolution of PNH clones after immunosuppressive therapy, and found increased incidence of PNH clone over time. The overall frequency of PNH clone in HAAA was 20.8% (15/72), which was comparable to that in IAA (27.8%, 112/403). Two thirds of those new PNH clones occurred in non-responders in HAAA. In conclusion, PNH clones are infrequent in HAAA compared to IAA at the time of diagnosis, but the overall frequency over time are comparable between the two groups of patients. In SAA/VSAA patients who are under the activated abnormal immunity, longer clinical course and relatively adequate residual hematopoietic cells serve as two important extrinsic factors for HSCs with PIGA-mutation to escape from immune attack and to expand. Disclosures No relevant conflicts of interest to declare.

scholarly journals Long-Term Outcome of Allogeneic Stem Cell Transplantation in Patients with Paroxysmal Nocturnal Hemoglobinuria with or without Aplastic Anemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2195-2195
Author(s):  
Sung-Eun Lee ◽  
Sung Soo Park ◽  
Young-Woo Jeon ◽  
Jae-Ho Yoon ◽  
Byung Sik Cho ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Acute Gvhd ◽  
Conditioning Regimen ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Pnh Clone

Abstract Background: Although recently, Eculizumab, humanized monoclonal antibody directed against complement component C5, has used increasingly for the patients with hemolytic paroxysmal nocturnal hemoglobinuria (PNH), allogeneic stem cell transplantation (allo-SCT) can be curative treatment option especially for PNH patients with combined aplastic anemia (AA). The aim of the present study was to evaluate long-term outcome of allo-SCT in patients with AA/PNH. In addition, patients with classic PNH who underwent allo-SCT in the pre-eculizumab era were also evaluated. Methods: Total of 33 patients with PNH clones underwent allogeneic SCT at our institution between Jan 1998 and Jan 2016. Among them, seven patients had classic PNH and 26 patients with cytopenia had AA/PNH (with bone marrow evidence of a concomitant AA). Results: There were 21 male and 12 female patients with a median age of 34 years (range, 13-56 years). Pre-transplant GPI-AP deficient neutrophils and erythrocytes were 5.6% (0-92) and 21% (0-98.5), respectively. Median white blood cell, absolute neutrophil count, hemoglobin, and platelet at transplant were 2.4×109/L, 0.8×109/L, 7.7 g/dL, and 27×109/L, respectively. Median LDH level was 727 U/L (232-7721 U/L) and 19 (58%) patients had LDH ≥1.5x upper limit of normal. Classic PNH (n=7) and AA/PNH [SAA (n=15), VSAA (n=9), or non-SAA (n=2)] received SCT from HLA-matched sibling (MSD, n=24), unrelated (URD, n=7), or haplo-identical donor (Haplo-SCT, n=2). Since 2003, the conditioning regimen for MSD-SCT was changed from Busulfex (12.8 mg/kg) + cyclophosphamide (CY, 120 mg/kg) to fludarabine (180 mg/m2) + CY (100 mg/kg) + rATG (10 mg/kg). The conditioning regimen for URD-SCT and Haplo-SCT were TBI (800 cGy) + CY (100-120 mg/kg) ± rATG (2.5 mg/kg) and TBI 600cGy + Fludarabine (150 mg/m2) + rATG (5 mg/kg), respectively. After a median follow-up of 57 months (range 6.0-151.3), the 5-year estimated OS rates were 87.9 ± 5.7%. Four patients died of treatment-related mortality (TRM), including acute GVHD (n=1), pneumonia (n = 2), and cerebral hemorrhage (n=1), respectively. Except one patient with early TRM, 32 patients engrafted. Two patients who experienced delayed graft-failure received second transplant and recovered. The cumulative incidence of acute GVHD (≥grade II) and chronic GVHD was 27.3 ± 7.9% and 18.7 ± 7.0%, respectively. Among 25 patients with available follow-up data, PNH clone disappeared at median 3.0 months (range 0.7-45.5) after SCT and reemerging of PNH clones was observed in two patients; one patient showed re-appearance of 2.6% GPI-negative neutrophils at 12 months without PNH symptoms, but disappeared again at 21 months. Another patient suffered from labile graft and received a booster with peripheral blood stem cells. Conclusion: This study showed that long-term transplant outcome in patients with AA/PNH were comparable to that of allogeneic SCT in SAA (the 3-year estimated OS rates were 92.7 and 89 % for MSD-SCT and URD-SCT, respectively) at our institution (ASH Annual Meeting Abstracts 2012;120:4151). Reduced-intensity conditioning regimen was sufficient for the eradication of PNH clone in allogeneic SCT. Therefore, application of allogeneic SCT should be considered in PNH patients with AA in case of availability of well matched donor. Disclosures No relevant conflicts of interest to declare.

scholarly journals Impaired Hematopoiesis in Paroxysmal Nocturnal Hemoglobinuria/Aplastic Anemia Is Not Associated With a Selective Proliferative Defect in the Glycosylphosphatidylinositol-Anchored Protein-Deficient Clone

Blood ◽  
1997 ◽  
Vol 89 (4) ◽  
pp. 1173-1181 ◽  
Author(s):  
Jaroslaw P. Maciejewski ◽  
Elaine M. Sloand ◽  
Tadatsugu Sato ◽  
Stacie Anderson ◽  
Neal S. Young
Keyword(s):  
Protein Expression ◽  
Aplastic Anemia ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Surface Proteins ◽  
In Vitro Assays ◽  
Normal Numbers ◽  
Normal Volunteers ◽  
Cd34 Cells ◽  
Cd59 Expression

Abstract Paroxysmal nocturnal hemoglobinuria (PNH) results from somatic mutations in the PIG-A gene, leading to poor presentation of glycosylphosphatidylinositol (GPI)-anchored surface proteins. PNH frequently occurs in association with suppressed hematopoiesis, including frank aplastic anemia (AA). The relationship between GPI-anchored protein expression and bone marrow (BM) failure is unknown. To assess the hematopoietic defect in PNH, the numbers of CD34+ cells, committed progenitors (primary colony-forming cells [CFCs]), and long-term culture-initiating cells (LTC-ICs; a stem cell surrogate) were measured in BM and peripheral blood (PB) of patients with PNH/AA syndrome or patients with predominantly hemolytic PNH. LTC-IC numbers were extrapolated from secondary CFC numbers after 5 weeks of culture, and clonogenicity of LTC-ICs was determined by limiting dilution assays. When compared with normal volunteers (n = 13), PNH patients (n = 14) showed a 4.7-fold decrease in CD34+ cells and an 8.2-fold decrease in CFCs. LTC-ICs in BM and in PB were decreased 7.3-fold and 50-fold, respectively. Purified CD34+ cells from PNH patients had markedly lower clonogenicity in both primary colony cultures and in the LTC-IC assays. As expected, GPI-anchored proteins were decreased on PB cells of PNH patients. On average, 23% of monocytes were deficient in CD14, and 47% of granulocytes and 58% of platelets lacked CD16 and CD55, respectively. In PNH BM, 27% of CD34+ cells showed abnormal GPI-anchored protein expression when assessed by CD59 expression. To directly measure the colony-forming ability of GPI-anchored protein-deficient CD34+ cells, we separated CD34+ cells from PNH patients for the GPI+ and GPI− phenotype; CD59 expression was chosen as a marker of the PNH phenotype based on high and homogeneous expression on fluorescent staining. CD34+CD59+ and CD34+CD59− cells from PNH/AA patients showed similarly impaired primary and secondary clonogeneic efficiency. The progeny derived from CD34+CD59− cells were both CD59− and CD55−. A very small population of CD34+CD59− cells was also detected in some normal volunteers; after sorting, these CD34+CD59− cells formed normal numbers of colonies, but their progeny showed lower CD59 levels. Our results are consistent with the existence of PIG-A–deficient clones in some normal individuals. In PNH/AA, progenitor and stem cells are decreased in number and function, but the proliferation in vitro is affected similarly in GPI-protein–deficient clones and in phenotypically normal cells. As measured in the in vitro assays, expansion of PIG-A– clones appears not be caused by an intrinsic growth advantage of cells with the PNH phenotype.

Bone Marrow Histology in Patients with Paroxysmal Nocturnal Hemoglobinuria.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4215-4215
Author(s):  
Sandra van Bijnen ◽  
Konnie Hebeda ◽  
Petra Muus
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Aplastic Anemia ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Plasma Cells ◽  
Bone Marrow Failure ◽  
Clone Size ◽  
Immune Mediated ◽  
Lymphoid Nodules ◽  
Pnh Clone

Abstract Abstract 4215 Introduction Paroxysmal Nocturnal Hemoglobinuria (PNH) is a disease of the hematopoietic stem cell (HSC) resulting in a clone of hematopoietic cells deficient in glycosyl phosphatidyl inositol anchored proteins. The clinical spectrum of PNH is highly variable with classical hemolytic PNH at one end, and PNH in association with aplastic anemia (AA/PNH) or other bone marrow failure states at the other end. It is still largely unknown what is causing these highly variable clinical presentations. Immune-mediated marrow failure has been suggested to contribute to the development of a PNH clone by selective damage to normal HSC. However, in classic PNH patients with no or only mild cytopenias, a role for immune mediated marrow failure is less obvious. No series of trephine biopsies has been previously documented of patients with PNH and AA/PNH to investigate the similarities and differences in these patients. Methods We have reviewed a series of trephine biopsies of 41 PNH patients at the time the PNH clone was first detected. The histology was compared of 27 patients with aplastic anemia and a PNH clone was compared to that of 14 patients with classic PNH. Age related cellularity, the ratio between myeloid and erythroid cells (ME ratio), and the presence of inflammatory cells (mast cells, lymphoid nodules and plasma cells) were evaluated. The relation with clinical and other laboratory parameters of PNH was established. Results Classic PNH patients showed a normal or hypercellular marrow in 79% of patients, whereas all AA/PNH patients showed a hypocellular marrow. Interestingly, a decreased myelopoiesis was observed not only in AA/PNH patients but also in 93% of classic PNH patients, despite normal absolute neutrophil counts (ANC ≥ 1,5 × 109/l) in 79% of these patients. The number of megakaryocytes was decreased in 29% of classic PNH patients although thrombocytopenia (< 150 × 109/l) was only present in 14% of the patients. Median PNH granulocyte clone size was 70% (range 8-95%) in classic PNH patients, whereas in AA/PNH patients this was only 10% (range 0.5-90%). PNH clones below 5% were exclusively detected in the AA/PNH group. Clinical or laboratory evidence of hemolysis was present in all classical PNH patients and in 52% of AA/PNH patients and correlated with PNH granulocyte clone size. Bone marrow iron stores were decreased in 71% of classic PNH patients. In contrast, increased iron stores were present in 63% of AA/PNH patients, probably reflecting their transfusion history. AA/PNH patients showed increased plasma cells in 15% of patients and lymphoid nodules in 37%, versus 0% and 11% in classic PNH. Increased mast cells (>2/high power field) were three times more frequent in AA/PNH (67%) than in PNH (21%). Conclusion Classic PNH patients were characterized by a more cellular bone marrow, increased erythropoiesis, larger PNH clones and clinically by less pronounced or absent peripheral cytopenias and more overt hemolysis. Decreased myelopoiesis and/or megakaryopoiesis was observed in both AA/PNH and classic PNH patients, even in the presence of normal peripheral blood counts, suggesting a role for bone marrow failure in classic PNH as well. More prominent inflammatory infiltrates were observed in AA/PNH patients compared to classical PNH patients. Disclosures: No relevant conflicts of interest to declare.

Screening Patients with Myelodysplastic Syndrome and Aplastic Anemia for Paroxysmal Nocturnal Hemoglobinuria Clones: A Retrospective Study,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3426-3426 ◽  
Author(s):  
Andrew Shih ◽  
Ian H. Chin-Yee ◽  
Ben Hedley ◽  
Mike Keeney ◽  
Richard A. Wells ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Retrospective Study ◽  
Aplastic Anemia ◽  
Board Of Directors ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Bone Marrow Failure ◽  
Cell Surface Expression ◽  
Advisory Committees ◽  
Hematopoietic Stem ◽  
Pnh Clone

Abstract Abstract 3426 Introduction: Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare disorder due to a somatic mutation in the hematopoietic stem cell. The introduction of highly sensitive flow cytometric and aerolysin testing have shown the presence of PNH clones in patients with a variety of other hematological disorders such as aplastic anemia (AA) and myelodysplasic syndrome (MDS). It is hypothesized that patients with these disorders and PNH clones may share an immunologic basis for marrow failure with relative protection of the PNH clone, due to their lack of cell surface expression of immune accessory proteins. This is supported by the literature showing responsiveness in AA and MDS to immunosuppressive treatments. Preliminary results from a recent multicenter trial, EXPLORE, notes that PNH clones can be seen in 70% of AA and 55% of MDS patients, and therefore there may be utility in the general screening of all patients with bone marrow failure (BMF) syndromes. Furthermore, it has been suggested that the presence of PNH cells in MDS is a predictive biomarker that is clinically important for response to immunosuppressive therapy. Methods: Our retrospective cohort study in a tertiary care center used a high sensitivity RBC and FLAER assay to detect PNH clones as small as 0.01%. Of all patients screened with this method, those with bone marrow biopsy and aspirate proven MDS, AA, or other BMF syndromes (defined as unexplained cytopenias) were analysed. Results from PNH assays were compared to other clinical and laboratory parameters such as LDH. Results: Overall, 102 patients were initially screened over a 12 month period at our center. 30 patients were excluded as they did not have biopsy or aspirate proven MDS, AA, or other BMF syndromes. Of the remaining 72 patients, four patients were found to have PNH clones, where 2/51 had MDS (both RCMD, IPSS 0) [3.92%] and 2/4 had AA [50%]. The PNH clone sizes of these four patients were 0.01%, 0.01%, 0.02%, and 1.7%. None of the MDS patients with known recurrent karyotypic abnormalities had PNH clones present. Only one of the four patients had a markedly increased serum LDH level. Conclusions: Our retrospective study indicates much lower incidence of PNH clones in MDS patients or any patients with BMF syndromes when compared to the preliminary data from the EXPLORE trial. There is also significant disagreement in other smaller cohorts in regards to the incidence of PNH in AA and MDS. Screening for PNH clones in patients with bone marrow failure needs further study before adoption of widespread use. Disclosures: Keeney: Alexion Pharmaceuticals Canada Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees. Wells:Alexion Pharmaceuticals Canada Inc: Honoraria. Sutherland:Alexion Pharmaceuticals Canada Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees.

scholarly journals Genetic defects underlying paroxysmal nocturnal hemoglobinuria that arises out of aplastic anemia

Blood ◽  
1995 ◽  
Vol 86 (12) ◽  
pp. 4656-4661 ◽  
Author(s):  
S Nagarajan ◽  
RA Brodsky ◽  
NS Young ◽  
ME Medof
Keyword(s):  
Aplastic Anemia ◽  
Rna Splicing ◽  
Antithymocyte Globulin ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Rt Pcr ◽  
Chain Reaction ◽  
The Third ◽  
Mrna Transcripts ◽  
Polymerase Chain

Treatment of severe aplastic anemia with antithymocyte globulin (ATG) and cyclosporin leads to clinical remission in a large proportion of patients. As many as 10% to 57% of these patients, however, develop paroxysmal nocturnal hemoglobinuria (PNH). We and others have observed that this secondary PNH appears to be more indolent than classical PNH, which results from an acquired mutation in the PIG-A gene. In the present study, we compared PIG-A mRNA transcripts in affected cells from patients with secondary PNH and patients with classical PNH. All four of our aplastic patients who developed PNH had a negative Ham test at diagnosis. Two of the four showed a positive Ham test within 3 months after ATG/cyclosporin administration, one developed a positive test at 6 months, and another at 18 months after immunosuppressive therapy. All four patients remain transfusion-independent with no thrombotic episodes after a mean follow-up of 30 months (range, 6 to 63 months). Reverse transcription-polymerase chain reaction (RT-PCR) of PIG-A transcripts in DAF-/CD59- neutrophils or lymphocyte lines of the four patients showed PIG-A abnormalities in all cases. Transition of C163 to T was found in one, a 14-bp deletion (positions 1141 to 1154) was found in the second, deletion of C39 was found in the third, and two mutations, transition of C55 to T and transversion of T762 to A, were found in the fourth. These abnormalities compared with findings of abnormal RNA splicing causing a 133-bp deletion, a 4-bp insertion (between positions 578 and 579), loss of A767, and loss of C575 in four patients with primary PNH. We conclude that secondary PNH that evolves out of aplastic anemia, like classical PNH, is associated with mutations in the PIG-A gene. The apparent indolent nature of this disease probably reflects early detection.

scholarly journals Paroxysmal Nocturnal Hemoglobinuria: An Underestimated Cause of Pediatric Thromboembolism

TH Open ◽  
2020 ◽  
Vol 04 (01) ◽  
pp. e36-e39
Author(s):  
Christina Griesser ◽  
Michael Myskiw ◽  
Werner Streif
Keyword(s):  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Clinical Symptoms ◽  
Bone Marrow Failure ◽  
Flow Cytometric Analysis ◽  
Routine Diagnostics ◽  
Glycosyl Phosphatidylinositol ◽  
Vein Thrombosis ◽  
Flow Cytometric ◽  
Appropriate Treatment

AbstractParoxysmal nocturnal hemoglobinuria (PNH) is a chronic disease caused by complement-mediated hemolysis. Clinical symptoms include intravascular hemolysis, nocturnal hemoglobinuria, thromboses, cytopenia, fatigue, abdominal pain, and a strong tendency toward bone marrow failure. It is a rare disease, especially in children, with high mortality rates without appropriate treatment.We here present the case of a 17-year-old girl with unprovoked muscle vein thrombosis. Flow cytometric analysis showed deficiency of glycosyl-phosphatidylinositol-anchored membrane proteins on all three hematopoietic cell lines and confirmed the diagnosis of PNH. Treatment with the monoclonal antibody eculizumab achieved long-term remission.As flow cytometry is normally not part of the routine diagnostics for pediatric thrombosis, awareness is crucial and PNH is important to consider in all children with thrombosis at atypical sites and abnormalities in blood counts with regard to hemolysis and cytopenia.

Evolution of GPI-Deficient Clones Predicts Clinical Course in Paroxysmal Nocturnal Haemoglobinuria.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 172-172 ◽  
Author(s):  
Stephen J. Richards ◽  
Matthew J. Cullen ◽  
Anita J. Dickinson ◽  
Claire Hall ◽  
Anita Hill ◽  
...  
Keyword(s):  
Aplastic Anemia ◽  
Clinical Course ◽  
Spontaneous Remission ◽  
Red Cells ◽  
Red Cell ◽  
Clone Size ◽  
Clinical Behavior ◽  
The Mean ◽  
Pnh Clone

Abstract Flow cytometric analysis of GPI-linked antigens has had a major impact on the diagnosis of PNH. Significant numbers of patients with aplastic anemia have small PNH clones, and due to the precision in clone size measurement, reliable serial monitoring can now be undertaken although the clinical value of this is not proven. From our series of 234 PNH patients, we analysed clinical correlates between disease type and red cell and granulocyte peripheral blood clone sizes as determined by flow cytometry at presentation. For hemolytic patients (n = 99) the mean PNH clone sizes were: granulocytes 84.8%; red cells 45.3% (type III cells 33.6%). For aplastic patients (no macroscopic hemolysis) the mean clone sizes were: granulocytes 18.5%; red cells 6.4% (type III cells 4.5%). The two groups were statistically different (Mann Whitney U; P<0.001). Monitoring of PNH clones in 86 of these patients who had at least 3 samples over a minimum of 12 months (mean 55 months; range 15–174) not only showed distinct groups of patients with highly characteristic patterns of disease but also provided insights into the incidence of spontaneous remission, progression from aplastic to hemolytic disease, and development of leukemia. Firstly, hemolytic patients that present with >90% granulocyte clones (n = 30; mean follow up 48 months) with virtually all their hematopoiesis maintained from PNH stem cells have clone sizes that remain stable and their clinical behavior suggests that their PNH can persist for up to 40 years. The second group of patients (n = 16) were those with hemolytic PNH with granulocyte clones of <90%. Mean granulocyte clone size at presentation was 68.4% (range 34.7– 90%) with a mean follow-up of 66 months (range 24–164). Of these, 6 showed stable clone sizes, 2 increasing clone size, and 8 showing reductions in granulocyte clone size. The third group were those presenting with aplastic anemia (n = 34). This group showed the most significant variation in clone size and clinical behavior. Of the 12 patients with persistent aplastic anemia, the majority had slowly increasing clone sizes with 5 patients progressing to hemolytic PNH after a variable time period ranging from 26 to 79 months. Only 3 patients developed MDS or AML. Two of these were from the >90% granulocyte clone group (2/30) and developed as a terminal event, one with GPI-MDS, and the second with a rapid emergence of GPI+MDS. One patient in the aplastic group showed progression to AML (1/34). 27% of patients had an improvement in cytopenias with concurrent decrease in PNH clone size. For hemolytic patients with granulocyte clones of <90%, the 8 patients with falling clone sizes had improving blood counts. The PNH granulocyte clone halved in a mean of 74 months. Of the patients with aplastic anemia, 15 showed resolution of anemia with normalization of counts and all but one had an associated fall in granulocyte PNH clone sizes. Eleven patients have been treated in clinical trials of the anti-complement antibody, eculizumab, for a period of up to 2 years and over this period the proportion of PNH granulocytes has remained stable. This data demonstrates that the size and type of granulocyte and red cell PNH clones at presentation predicts the clinical course for individual patients assisting long term clinical management planning. Moreover, regular clone size monitoring predicts the likelihood of spontaneous reduction in the PNH clone and potentially for spontaneous remission.

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