CD4(+)CD7(-) T cells compose the dominant T-cell clone in the peripheral blood of patients with Sézary syndrome.
BACKGROUND
Absence of CD7 antigen expression in T cells defines a subset of normal CD4(+) CD45RO(+) CD45RA(-) memory cells and is furthermore observed in Sézary syndrome (SS).


OBJECTIVE
Our purpose was to identify circulating T-cell clones in patients with SS and to elucidate whether the dominant T-cell clones express the CD7 antigen.


METHODS
Peripheral blood lymphocytes of patients with SS were analyzed by two-color flow cytometry using antibodies to the V beta region of the T cell receptor (TCR) in combination with an antibody to CD7. In addition, T cells were analyzed for TCR-gamma gene rearrangement by polymerase chain reaction (PCR) techniques.


RESULTS
Clonal T-cell expansion was detected in 7 patients with SS by immunostaining of the TCR V beta regions. PCR analysis confirmed the presence of dominant T cell clones. Double-immunostaining revealed that in each case cells of the clonal V beta TCR rearrangement homogeneously express the CD4(+)CD7(-) phenotype. Furthermore, CD4(+)CD7(-) cells express the CD15s antigen but lack expression of CD26 and CD49d.


CONCLUSIONS
Expansion of clonal T cells strongly correlates with the expansion of CD4(+)CD7(-) T cells in 7 tested patients with SS. This supports our model that a subset of late differentiated, normal CD4(+)CD7(-) memory T cells may represent the physiologic counterpart of Sézary cells. Monitoring of circulating T cells with the CD4(+)CD7(-)CD15s(+)CD26(-)CD49d(-) phenotype proved to be useful for the identification of clonal T cells in patients with SS.
Rappl
G
G
Department of Dermatology, The Saarland University Hospital, Homburg/Saar, Germany.
Muche
J M
JM
Abken
H
H
Sterry
W
W
Tilgen
W
W
Ugurel
S
S
Reinhold
U
U
D000368:Aged; D019011:Antigens, CD7 / Q000032:analysis*; D015704:CD4 Antigens / Q000032:analysis*; D002454:Cell Differentiation; D002455:Cell Division; D002999:Clone Cells; D005260:Female; D005434:Flow Cytometry; D019675:Genes, T-Cell Receptor gamma; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012751:Sezary Syndrome / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D019011:Antigens, CD7; D015704:CD4 Antigens