title: Altered immunophenotypic features of peripheral blood platelets in myelodysplastic syndromes.
abstract: BACKGROUND
  Multiparameter flow cytometric analysis of bone marrow and peripheral blood cells has proven to be of help in the diagnostic workup of myelodysplastic syndromes. However, the usefulness of flow cytometry for the detection of megakaryocytic and platelet dysplasia has not yet been investigated. The aim of this pilot study was to evaluate by flow cytometry the diagnostic and prognostic value of platelet dysplasia in myelodysplastic syndromes.
  
  
  METHODS
  We investigated the pattern of expression of distinct surface glycoproteins on peripheral blood platelets from a series of 44 myelodysplastic syndrome patients, 20 healthy subjects and 19 patients with platelet alterations associated to disease conditions other than myelodysplastic syndromes. Quantitative expression of CD31, CD34, CD36, CD41a, CD41b, CD42a, CD42b and CD61 glycoproteins together with the PAC-1, CD62-P, fibrinogen and CD63 platelet activation-associated markers and platelet light scatter properties were systematically evaluated.
  
  
  RESULTS
  Overall, flow cytometry identified multiple immunophenotypic abnormalities on platelets of myelodysplastic syndrome patients, including altered light scatter characteristics, over-and under expression of specific platelet glycoproteins and asynchronous expression of CD34; decreased expression of CD36 (n = 5), CD42a (n = 1) and CD61 (n = 2), together with reactivity for CD34 (n = 1) were only observed among myelodysplastic syndrome cases, while other alterations were also found in other platelet disorders. Based on the overall platelet alterations detected for each patient, an immunophenotypic score was built which identified a subgroup of myelodysplastic syndrome patients with a high rate of moderate to severe alterations (score>1.5; n = 16) who more frequently showed thrombocytopenia, megakaryocytic dysplasia and high-risk disease, together with a shorter overall survival.
  
  
  CONCLUSIONS
  Our results show the presence of altered phenotypes by flow cytometry on platelets from around half of the myelodysplastic syndrome patients studied. If confirmed in larger series of patients, these findings may help refine the diagnostic and prognostic assessment of this group of disorders.
authors.affiliation: Disciplina de Hematologia e Hemoterapia, Departamento de Oncologia Clínica, Universidade Federal de São Paulo, UNIFESP, R. Botucatu 740, V. Clementino, 04023-900, São Paulo, Brazil.  yamamoto@unifesp.br.
authors.forename: Alex F
authors.initials: AF
authors.lastname: Sandes
authors.forename: Mihoko
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Sergio
authors.initials: S
authors.lastname: Matarraz
authors.forename: Maria de Lourdes L F
authors.initials: Mde L
authors.lastname: Chauffaille
authors.forename: Sandra
authors.initials: S
authors.lastname: Quijano
authors.forename: Antonio
authors.initials: A
authors.lastname: López
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Oguro
authors.forename: Eliza Y S
authors.initials: EY
authors.lastname: Kimura
authors.forename: Alberto
authors.initials: A
authors.lastname: Orfao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000235:genetics* / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D001792:Blood Platelets / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D054641:Dual Specificity Phosphatase 2 / Q000235:genetics / Q000276:immunology; D005260:Female; D005340:Fibrinogen / Q000235:genetics / Q000276:immunology; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000276:immunology; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008533:Megakaryocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000276:immunology / Q000401:mortality / Q000473:pathology*; D010865:Pilot Projects; D015539:Platelet Activation / Q000235:genetics / Q000276:immunology; D011379:Prognosis; D012306:Risk; D012720:Severity of Illness Index; D015996:Survival Rate; D013921:Thrombocytopenia / Q000276:immunology / Q000401:mortality / Q000473:pathology*
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; D005340:Fibrinogen; C517032:DUSP2 protein, human; D054641:Dual Specificity Phosphatase 2