T cell receptor V gene usage by CD4+ and CD8+ peripheral blood T lymphocytes in immune thrombocytopenic purpura.
OBJECTIVE
To identify T cell expansions, i.e. increased frequencies of T cells using a particular T cell receptor (TCR) V alpha or V beta gene segment, in patients with immune thrombocytopenic purpura (ITP).


METHODS
The TCR repertoires of CD4+ and CD8+ peripheral blood lymphocytes of 16 patients with chronic ITP were analysed by staining with a panel of anti-TCR V alpha and V beta antibodies followed by flow cytometry.


RESULTS
Four of the 16 patients exhibited a total of 6 expansions of CD8+ T cells using a particular V beta segment, but no expansions were detected in the CD4+ subset. For three of the expansions where a follow-up blood sample after treatment with intravenous immunoglobulin was available, only one expansion remained.


CONCLUSIONS
Overall T cell expansion frequency was the same as in healthy individuals. However, the presence of expansions that normalized with treatment suggests the presence of specific T cells implicated in the pathogenesis of ITP.
Hedlund-Treutiger
I
I
Sach's Children's Hospital, Karolinska Institutet at Södersjukhuset, Stockholm, Sweden. iris.treutiger@sos.ki.se
Elinder
G
G
Wigzell
H
H
Grunewald
J
J
Wahlström
J
J
D000293:Adolescent; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D019674:Genes, T-Cell Receptor beta / Q000276:immunology*; D006801:Humans; D008297:Male; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology*