title: Clonally expanded T-cells in the peripheral blood of patients with idiopathic Thrombocytopenic purpura and Helicobacter pylori infection.
abstract: Eradication of Helicobacter pylori leads to platelet recovery in some patients with idiopathic thrombocytopenic purpura (ITP). Therefore, the pathogenesis of a subgroup of ITP is probably associated with H pylori infection (H pylori-related ITP). If H pylori-related ITP is a definite subgroup of ITP, specific oligoclonal T-cells might accumulate in the peripheral blood (PB). To address this issue, we performed single-strand conformation polymorphism analysis of complementarity-determining region 3 (CDR3) of the T-cell receptor beta-chain genes of PB T-cells. Fourteen ITP patients with H pylori infection and 12 ageadjusted healthy volunteers were studied. Of the 14 patients, 8 patients (responders) exhibited a platelet response after successful H pylori eradication therapy, but 6 patients (nonresponders) did not. Vbeta5.2, Vbeta15, and Vbeta19 gene usage by clonally expanded T-cells in PB obtained before H pylori eradication therapy was significantly higher in responders than in nonresponders or healthy volunteers (Vbeta5.2, P = .023; Vbeta15, P = .004; Vbeta19, P = .036). Furthermore, an abrogation of clonally expanded T-cells was observed after therapy in some responders. These findings suggest that specific T-cell clones accumulate in H pylori-related ITP and that such clones may be associated with immune-mediated destruction of platelets.
authors.affiliation: Department of Haematology, Tokyo Women's Medical University, Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Ishiyama
authors.forename: Masanao
authors.initials: M
authors.lastname: Teramura
authors.forename: Koji
authors.initials: K
authors.lastname: Iwabe
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kato
authors.forename: Toshiko
authors.initials: T
authors.lastname: Motoji
mesh_terms: D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000382:microbiology / Q000473:pathology; D016022:Case-Control Studies; D002999:Clone Cells / Q000276:immunology / Q000473:pathology; D022801:Complementarity Determining Regions / Q000235:genetics; D005260:Female; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D018807:Polymorphism, Single-Stranded Conformational; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology* / Q000382:microbiology*; D013601:T-Lymphocytes / Q000473:pathology*
chemical_list: D022801:Complementarity Determining Regions