Heterogeneous immunophenotype of granular lymphocyte expansions: differential expression of the CD8 alpha and CD8 beta chains.
In this study, we have evaluated 14 large granular lymphocyte (LGL) expansions, 11 of which were CD8+. Analysis of the membrane expression of the alpha and beta chains of the CD8 antigen, using specific monoclonal antibodies (MoAbs), has shown that LGL expansions with the CD3+, CD4+, CD8+, CD57+ T-cell receptor (TcR) alpha beta phenotype bear the CD8 alpha/alpha isoform, while the CD3+, CD4-, CD8+, CD57+ TcR alpha beta samples were positive for both the CD8 alpha and CD8 beta chains. These data were confirmed also by messenger RNA analysis. One additional case, with a peculiar phenotype (CD3-, CD2-, CD4-, CD8+, CD57-) and a germline configuration of the TcR beta and gamma chain genes, expressed only the CD8 alpha chain. After additional phenotypic analysis with a wider panel of MoAbs, it was found that the beta chain of the interleukin-2 receptor was constitutively expressed on the majority of the samples tested, and that most of the monoclonal samples coexpressed CD45RA/R0 antigens. Using MoAbs directed against the variable regions of the TcR beta chain, we could show a preferential V beta region restriction in the CD8+ monoclonal cases. This more extensive characterization of CD8+ LGL expansions has further documented the marked heterogeneity within this rare condition and allowed a better phenotypic dissection between the monoclonal and polyclonal cases.
de Totero
D
D
Istituto Nazionale per la Ricerca sul Cancro (IST), Genova, Italy.
Tazzari
P L
PL
DiSanto
J P
JP
di Celle
P F
PF
Raspadori
D
D
Conte
R
R
Gobbi
M
M
Ferrara
G B
GB
Flomenberg
N
N
Lauria
F
F
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis*; D016516:CD4-CD8 Ratio; D016827:CD8 Antigens / Q000032:analysis* / Q000096:biosynthesis; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D008232:Lymphoproliferative Disorders / Q000276:immunology*; D046911:Macromolecular Substances; D008297:Male; D008875:Middle Aged; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D016827:CD8 Antigens; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell