title: Paroxysmal Nocturnal Hemoglobinuria is rare cause for thrombosis of the intra-abdominal veins in the ethnic Indian population - results from FLAER-based flowcytometry screening.
abstract: BACKGROUND
  Paroxysmal nocturnal hemoglobinuria (PNH) may present as cytopenia, hemolysis, or thrombosis at unusual sites including splanchnic vessels. Thrombosis of the portal veins and hepatic veins are associated with thrombophilic risk factors: deficiencies of protein C, protein S, and antithrombin, positivity for antiphospholipid antibodies, and factor V Leiden mutation. There is limited information regarding PNH presenting primarily as a thrombotic event. We prospectively screened 142 consecutive patients with intrabdominal thrombosis and 106 controls with fluorescently labeled inactive toxin aerolysin (FLAER)-based flowcytometry to assess the frequency of PNH as a thrombophilic risk factor in patients with intra-abdominal thrombosis.
  
  
  METHODS
  Granulocytes of patients and controls were screened with CD 24 and FLAER and monocytes with CD 14 and FLAER. Dual negativity of >1% events in both lineages was interpreted as a positive PNH clone. Screening for thrombophilia risk factors was carried out.
  
  
  RESULTS
  Two (1.4%) cases had large PNH clones. RBC also demonstrated the PNH defect. Thrombophilia risk factors were as follows: deficiency of protein S, protein C, and antithrombin in 13.4%, 4.9%, and 2.1%, respectively, and positivity for anti-beta-2 glycoprotein 1, anticardiolipin antibodies, and lupus anticoagulant in 9.2%, 1.4%, and 0.7%, respectively. Factor V Leiden mutation was seen in 1.4% patients.
  
  
  CONCLUSIONS
  PNH was uncommon in patients with intra-abdominal thrombosis in the ethnic Indian population. Despite low positivity, screening by flowcytometry for PNH is of value in this group of patients because it provides an opportunity to rapidly establish the diagnosis of this treatable disorder, which might otherwise be missed if the initial presentation is only thrombotic.
authors.affiliation: Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Ahluwalia
authors.forename: Shano
authors.initials: S
authors.lastname: Naseem
authors.forename: Man Updesh Singh
authors.initials: MU
authors.lastname: Sachdeva
authors.forename: Parveen
authors.initials: P
authors.lastname: Bose
authors.forename: Sunil Kumar
authors.initials: SK
authors.lastname: Bose
authors.forename: Narender
authors.initials: N
authors.lastname: Kumar
authors.forename: Babu Ram
authors.initials: BR
authors.lastname: Thapa
authors.forename: Neelam
authors.initials: N
authors.lastname: Varma
authors.forename: Yogesh Kumar
authors.initials: YK
authors.lastname: Chawla
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000990:Antithrombin III / Q000378:metabolism; D001323:Autoantibodies / Q000097:blood; D001427:Bacterial Toxins; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006098:Granulocytes / Q000378:metabolism / Q000473:pathology; D006457:Hemoglobinuria, Paroxysmal / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000208:ethnology; D006503:Hepatic Veins / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D016682:Lupus Coagulation Inhibitor / Q000097:blood; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism / Q000473:pathology; D052899:Pore Forming Cytotoxic Proteins; D011169:Portal Vein / Q000378:metabolism / Q000503:physiopathology; D011446:Prospective Studies; D011486:Protein C / Q000378:metabolism; D017293:Protein S / Q000378:metabolism; D012307:Risk Factors; D019851:Thrombophilia / Q000097:blood / Q000175:diagnosis / Q000208:ethnology / Q000209:etiology*; D013927:Thrombosis / Q000097:blood / Q000175:diagnosis / Q000208:ethnology / Q000209:etiology*
chemical_list: D001323:Autoantibodies; D001427:Bacterial Toxins; D016682:Lupus Coagulation Inhibitor; D052899:Pore Forming Cytotoxic Proteins; D011486:Protein C; D017293:Protein S; C032676:aerolysin; D000990:Antithrombin III
keywords: Budd Chiari syndrome; Intra-abdominal thrombosis; extra hepatic portal vein thrombosis; paroxysmal nocturnal hemoglobinuria; thrombophilia