title: T-cell abnormalities are present at high frequencies in patients with hypereosinophilic syndrome.
abstract: BACKGROUND
  A T-cell clone, thought to be the source of eosinophilopoietic cytokines, identified by clonal rearrangement of the T-cell receptor and by the presence of aberrant T-cell immunophenotype in peripheral blood defines lymphocytic variant of hypereosinophilic syndrome (L-HES).
  
  
  METHODS
  Peripheral blood samples from 42 patients who satisfied the diagnostic criteria for HES were studied for T-cell receptor clonal rearrangement by polymerase chain reaction according to BIOMED-2. The T-cell immunophenotype population was assessed in peripheral blood by flow cytometry. The FIP1L1-PDGFRA fusion gene was detected by nested polymerase chain reaction.
  
  
  RESULTS
  Forty-two HES patients (18 males and 24 females) with a median age at diagnosis of 56 years (range 17-84) were examined in this study. Their median white blood cell count was 12.9 x 10(9)/L (range 5.3-121), with an absolute eosinophil count of 4.5 x 10(9)/L (range 1.5-99) and a median eosinophilic bone marrow infiltration of 30% (range 11-64). Among the 42 patients, clonal T-cell receptor rearrangements were detected in 18 patients (42.8%). Patients with T-cell receptor clonality included: T-cell receptor beta in 15 patients (35%), T-cell receptor gamma in 9 (21%) and T-cell receptor delta in 9 (21%) patients, respectively. Clonality was detected in all three T-cell receptor loci in 4 cases, in two loci in 7 patients and in one T-cell receptor locus in the remaining 7 patients. The FIP1L1-PDGFRA fusion transcript was absent in all but 2 patients with T-cell receptor clonality. Three patients out of 42 revealed an aberrant T-cell immunophenotype. In some patients, an abnormal CD4:CD8 ratio was demonstrated.
  
  
  CONCLUSIONS
  T-cell abnormalities are present at high frequencies in patients with HES.
authors.affiliation: Department of Haematology and Bone Marrow Transplantation, Silesian Medical University, Dabrowski Street 25, Katowice, Poland. ghelbig@o2.pl
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Helbig
authors.forename: Agata
authors.initials: A
authors.lastname: Wieczorkiewicz
authors.forename: Joanna
authors.initials: J
authors.lastname: Dziaczkowska-Suszek
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Majewski
authors.forename: Slawomira
authors.initials: S
authors.lastname: Kyrcz-Krzemien
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016516:CD4-CD8 Ratio; D005260:Female; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor / Q000235:genetics / Q000276:immunology*; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor / Q000235:genetics / Q000276:immunology*; D006801:Humans; D017681:Hypereosinophilic Syndrome / Q000097:blood / Q000235:genetics / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D015514:Oncogene Proteins, Fusion / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D039221:mRNA Cleavage and Polyadenylation Factors / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*
chemical_list: D015514:Oncogene Proteins, Fusion; D039221:mRNA Cleavage and Polyadenylation Factors; C479819:FIP1L1-PDGFRA fusion protein, human; D020796:Receptor, Platelet-Derived Growth Factor alpha