title: Paroxysmal nocturnal hemoglobinuria associated with in vitro inhibition of erythropoiesis by bone marrow T lymphocytes.
abstract: BACKGROUND
  The etiology of bone marrow failure, a prominent feature of paroxysmal nocturnal hemoglobulinuria, is presently unknown.
  
  
  OBJECTIVE
  To evaluate the possible influence of cellular immune mechanisms in the bone marrow failure of PNH.
  
  
  METHODS
  We studied marrow erythroid colony formation in a patient with paroxysmal nocturnal hemoglobinuria without hypoplastic/aplastic marrow complications.
  
  
  RESULTS
  In vitro assays revealed a pronounced inhibition of primitive erythroid (BFU-E) progenitor cell growth by marrow T lymphocytes. Removal of T cells prior to culture resulted in a 4.5-fold enhancement of BFU-E numbers. Reevaluation of in vitro erythropoiesis during steroid administration indicated a persistent, albeit less prominent, T cell inhibitory effect.
  
  
  CONCLUSIONS
  Our findings provide the first direct evidence for a cellular immune inhibitory phenomenon accompanying PNH.
authors.affiliation: Hemopoiesis Unit, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel. merchav@tx.technion.ac.il
authors.forename: S
authors.initials: S
authors.lastname: Merchav
authors.forename: I
authors.initials: I
authors.lastname: Tatarsky
authors.forename: J
authors.initials: J
authors.lastname: Chezar
authors.forename: R
authors.initials: R
authors.lastname: Sharon
authors.forename: H
authors.initials: H
authors.lastname: Rosenbaum
authors.forename: Y
authors.initials: Y
authors.lastname: Schechter
mesh_terms: D000328:Adult; D000753:Anemia, Refractory; D016022:Case-Control Studies; D015672:Erythroid Precursor Cells / Q000378:metabolism*; D004920:Erythropoiesis / Q000276:immunology*; D005260:Female; D006457:Hemoglobinuria, Paroxysmal / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic; D013601:T-Lymphocytes / Q000276:immunology*