title: Minor population of CD55-CD59- blood cells predicts response to immunosuppressive therapy and prognosis in patients with aplastic anemia.
abstract: We investigated the clinical significance of a minor population of paroxysmal nocturnal hemoglobinuria (PNH)-type blood cells in patients with acquired aplastic anemia (AA). We quantified CD55-CD59- granulocytes and red blood cells (RBCs) in peripheral blood from 122 patients with recently diagnosed AA and correlated numbers of PNH-type cells and responses to immunosuppressive therapy (IST). Flow cytometry detected 0.005% to 23.1% of GPI-AP- cells in 68% of patients with AA. Sixty-eight of 83 (91%) patients with an increased proportion of PNH-type cells (PNH+) responded to antithymocyte globulin (ATG) + cyclosporin (CsA) therapy, whereas 18 of 39 (48%) without such an increase (PNH-) responded. Failure-free survival rates were significantly higher (64%) among patients with PNH+ than patients with PNH- (12%) at 5 years, although overall survival rates were comparable between the groups. Numbers of PNH-type and normal-type cells increased in parallel among most patients with PNH+ who responded to IST, suggesting that these cells are equally sensitive to immune attack. These results indicate that a minor population of PNH-type cells represents a reliable marker of a positive IST response and a favorable prognosis among patients with AA. Furthermore, immune attack against hematopoietic stem cells that allows PNH clonal expansion might occur only at the onset of AA.
authors.affiliation: Cellular Transplantation Biology, Division of Cancer Medicine, Kanazawa University Graduate School of Medical Science, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Sugimori
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Chuhjo
authors.forename: Xingmin
authors.initials: X
authors.lastname: Feng
authors.forename: Hirohito
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takami
authors.forename: Masanao
authors.initials: M
authors.lastname: Teramura
authors.forename: Hideaki
authors.initials: H
authors.lastname: Mizoguchi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Omine
authors.forename: Shinji
authors.initials: S
authors.lastname: Nakao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000741:Anemia, Aplastic / Q000097:blood* / Q000188:drug therapy* / Q000276:immunology / Q000401:mortality; D015703:Antigens, CD / Q000097:blood / Q000235:genetics; D000961:Antilymphocyte Serum / Q000627:therapeutic use; D018958:CD55 Antigens / Q000097:blood* / Q000235:genetics; D018957:CD59 Antigens / Q000097:blood* / Q000235:genetics; D002869:Chromosome Aberrations; D016572:Cyclosporine / Q000627:therapeutic use; D005260:Female; D005434:Flow Cytometry; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016019:Survival Analysis
chemical_list: D015703:Antigens, CD; D000961:Antilymphocyte Serum; D018958:CD55 Antigens; D018957:CD59 Antigens; D007166:Immunosuppressive Agents; D016572:Cyclosporine