title: Blood flow cytometry in Sézary syndrome: new insights on prognostic relevance and immunophenotypic changes during follow-up.
abstract: OBJECTIVE
  Sézary syndrome (SS) is characterized by erythroderma, generalized lymphadenopathy, and the presence of circulating atypical lymphocytes, which are difficult to identify by morphologic data.
  
  
  METHODS
  We revised our series of 107 patients in an attempt to better define the phenotypic aberrancies in blood at diagnosis and the immunophenotypic stability over time detected by flow cytometry. Polymerase chain reaction assay was also used to study CD26/dipeptidyl peptidase IV (DPPIV) gene methylation.
  
  
  RESULTS
  The most common aberrancies were represented by the lack of CD26 (96/107) or CD38 (101/107) expression and the presence of a "dim" CD3, CD4, or CD2 population. There was a high variability in CD7 expression. In total, 31% of the patients had phenotypical heterogeneity in CD26 and CD7 expression at diagnosis. The phenotype was stable over time in 73 of 95 patients with available follow-up data, while 22 of 95 patients developed changes in CD26, CD7, or CD2 expression. CD4+CD26- SS showed hypermethylation of the CpG islands for the promoter region of CD26/DPPIV. Multivariate analysis showed that CD26 expression is a favorable prognostic factor (hazard ratio, 2.94; P = .045).
  
  
  CONCLUSIONS
  We confirm the relevance of CD26 negativity in SS diagnosis and monitoring. Nevertheless, the presence of rare CD26+ cases suggests that a multiparameter flow cytometry approach should be used. Changes in methylation profile could account for phenotypical heterogeneity.
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Mauro
authors.initials: M
authors.lastname: Novelli
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Paolo
authors.initials: P
authors.lastname: Fava
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Cristina
authors.initials: C
authors.lastname: Sarda
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Renata
authors.initials: R
authors.lastname: Ponti
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Simona
authors.initials: S
authors.lastname: Osella-Abate
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Paola
authors.initials: P
authors.lastname: Savoia
authors.affiliation: Department of Public Health and Pediatrics, University of Torino, Torino, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Bergallo
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lisa
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and mariateresa.fierro@unito.it.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Fierro
authors.affiliation: From the Dermatologic Clinic, Department of Medical Sciences, and.
authors.forename: Pietro
authors.initials: P
authors.lastname: Quaglino
mesh_terms: D000328:Adult; D000368:Aged; D019011:Antigens, CD7 / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001783:Blood Flow Velocity / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012751:Sezary Syndrome / Q000175:diagnosis*; D012878:Skin Neoplasms / Q000175:diagnosis*
chemical_list: D019011:Antigens, CD7; D014408:Biomarkers, Tumor
keywords: CD26; CTCL; Flow cytometry; Hypermethylation; Immunophenotypic changes; Sézary syndrome