Analysis of B- and T-cell clonality and HLA class II alleles in patients with idiopathic thrombocytopenic purpura: correlation with Helicobacter pylori infection and response to eradication treatment.
Many authors have recently found a positive correlation between Helicobacter pylori infection and idiopathic thrombocytopenic purpura (ITP), the most common autoimmune hematological disorder. In order to clarify the pathogenic mechanism of H. pylori-associated ITP, we have investigated 52 consecutive ITP adult patients for Helicobacter pylori infection, B- and T-cell clonality and HLA class II alleles. Thirty-four ITP patients (65.4%) were infected by H. pylori and bacterium eradication was accompanied by a long-term platelet response in 17 (53.1%) of them. A B-cell clonality was found in three patients (5.8%, two patients H. pylori-negative and one patient H. pylori-positive). The ITP patients with H. pylori infection showed a HLA-DRB1*11, *14 and -DQB1*03 frequencies significantly higher and a -DRB1*03 frequency significantly lower than in H. pylori-negative patients. Moreover, an HLA-DQB1*03 pattern was associated with a higher probability of platelet response to eradication treatment. If our study documents the efficacy of eradication treatment in H. pylori-infected ITP patients, it may also help to identify different subgroups of ITP patients with probably different pathogeneses of thrombocytopenia and, finally, different responses to eradication treatment.
Veneri
Dino
D
Dipartimento di Medicina Clinica e Sperimentale, Sezione di Ematologia, Università di Verona.
De Matteis
Giovanna
G
Solero
Pietro
P
Federici
Francesca
F
Zanuso
Carla
C
Guizzardi
Elisabetta
E
Arena
Silvia
S
Gaio
Monica
M
Pontiero
Patrizia
P
Ricetti
Maria M
MM
Franchini
Massimo
M
D000328:Adult; D000368:Aged; D000483:Alleles; D001402:B-Lymphocytes / Q000276:immunology*; D002999:Clone Cells / Q000276:immunology; D005260:Female; D005802:Genes, MHC Class II / Q000276:immunology*; D006683:HLA-DQ Antigens / Q000235:genetics / Q000276:immunology; D006684:HLA-DR Antigens / Q000235:genetics / Q000276:immunology; D016481:Helicobacter Infections / Q000188:drug therapy / Q000235:genetics / Q000276:immunology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D016133:Polymerase Chain Reaction; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000188:drug therapy / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D013601:T-Lymphocytes / Q000276:immunology*
D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens