title: Significance of the detection of paroxysmal nocturnal hemoglobinuria clones in patients with multiple myeloma undergoing autologous stem cell transplantation.
abstract: OBJECTIVE
  There are reports about the presence of paroxysmal nocturnal hemoglobinuria (PNH) clones in multiple myeloma (MM), but these have been demonstrated only in red blood cells (RBCs) and the previous reports utilized an obsolete diagnostic method. We carried out a study to identify the clones by flow cytometry (FC) and to understand their clinical significance.
  
  
  METHODS
  A prospective study on consecutive patients with newly diagnosed MM who were candidates for autologous stem cell transplantation (ASCT) from 2008 to 2012. We screened peripheral blood samples by FC for CD55- and/or CD59-deficient RBC, neutrophils, and monocytes. PNH testing was carried out at diagnosis, before ASCT and 3 months after ASCT, as well as sporadically during MM remission and at disease relapse.
  
  
  RESULTS
  A total of 31 patients were included in the study. PNH clones reaching a median size of 10.8% (range 4.0-18.7%) were found in 10 patients (32.3%). Clones were detected at diagnosis in nine patients and 3 months after ASCT in one patient. A correlation between the presence of the clones and subclinical hemolysis was observed. Nevertheless, the presence of the clones did not influence the overall management and prognosis of the patients.
  
  
  CONCLUSIONS
  We confirmed findings of previous reports with current diagnostic guidelines and showed that although the size of the clones may be relatively large, their presence is probably not detrimental. The clinical significance of these clones and the possible mechanisms underlying their expansion in MM must be a subject of further investigation.
authors.affiliation: Department of Hematology, Metaxa Anticancer Hospital, Piraeus, Greece. Electronic address: vchatziantoniou@athenshematology.gr.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Chatziantoniou
authors.affiliation: Hematology and Flow Cytometry Laboratory, Metaxa Anticancer Hospital, Piraeus, Greece.
authors.forename: Stavroula
authors.initials: S
authors.lastname: Alexia
authors.affiliation: Department of Haematology, Athens University Medical School, Athens, Greece.
authors.forename: Kostas
authors.initials: K
authors.lastname: Konstantopoulos
authors.affiliation: Department of Hematology, Metaxa Anticancer Hospital, Piraeus, Greece.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Repousis
authors.affiliation: Department of Hematology, Metaxa Anticancer Hospital, Piraeus, Greece.
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Megalakaki
authors.affiliation: Department of Hematology, Metaxa Anticancer Hospital, Piraeus, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Kotsopoulou
authors.affiliation: Hematology and Flow Cytometry Laboratory, Metaxa Anticancer Hospital, Piraeus, Greece.
authors.forename: Pavlina
authors.initials: P
authors.lastname: Kylidou
authors.affiliation: Department of Haematology, Athens University Medical School, Athens, Greece.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Vassilakopoulos
authors.affiliation: Department of Haematology, Athens University Medical School, Athens, Greece.
authors.forename: Maria K
authors.initials: MK
authors.lastname: Angelopoulou
mesh_terms: D000368:Aged; D002999:Clone Cells; D018572:Disease-Free Survival; D004912:Erythrocytes / Q000473:pathology; D005260:Female; D006098:Granulocytes / Q000473:pathology; D018380:Hematopoietic Stem Cell Transplantation; D006457:Hemoglobinuria, Paroxysmal / Q000150:complications* / Q000473:pathology* / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000150:complications* / Q000473:pathology* / Q000628:therapy; D014182:Transplantation, Autologous
keywords: Autologous stem cell transplantation; Multiple myeloma; PIG-A gene; Paroxysmal nocturnal hemoglobinuria