12th Congress of the European Hematology ... - Haematologica

0206
POTENTIAL ROLE OF CMV IN THE ONTOGENY OF MONOCLONAL TCRαβ + /CD4 + T-LARGE
GRANULAR LYMPHOCYTE [LGL] LYMPHOCYTOSIS
R.C. Arancha, 1 A.C. Garcia-Montero, 1 J. Almeida Parra, 1
P. Barcena Carrasco, 1 S. Muñoz-Criado, 1 F. Ruiz-Cabello, 2 A. Orfao 1
1 Salamanca University SALAMANCA; 2 Virgen de las Nieves Hospital,
GRANADA, Spain
Background. Patients with TCR-Vβ13.1 + /CD4 + T-LGL lymphocytosis
display a common HLA-DRB1*0701 genotype and express identical
motifs in the CDR3-TCR-Vβ sequence, suggesting an antigen-driven
chronic T-cell stimulation origin for this particular disease. 1 Interestingly,
peripheral blood [PB] CMV-specific CD4 + T-cells from healthy adults
are mostly antigen-experienced cytotoxic T-cells, which show a marked
bias of the TCRVβ repertoire associated with certain HLA genotypes. 2
Of note, the expansion of CMV-specific TCR-Vβ13.1 + CD4 + T-cells was
associated with the HLA-DRB1*0701 allele. Thus, CMV would be a
good candidate to play a role in the ontogeny of monoclonal
TCRαβ + /CD4 + T-LGL lymphocytosis. Aims. To identify and characterize
the CMV-specific clonal CD4 + T-cells from patients with different T-cell
chronic lymphoproliferative disorders [CLPD]. Methods. PB samples from
patients with monoclonal TCRαβ + /CD4 + T-LGL lymphocytosis [n=12],
TCRαβ + /CD8 + LGL leukemias [n=2], TCRγδ + LGL leukemias [n=4] and
other CD4 + T-CLPD than LGL [n=9], were stimulated for 6h with both
CMV and EBV whole lysates. Identification of virus-specific CD4 + T-cells
was assessed by flow cytometry, through the detection of surface TNFα
on secreting cells. Soluble levels of IFNγ, TNFα, LTα, GM-CSF, IL-2, IL-
3, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12 and IL-13 in culture supernatants
were quantified using the Cytometric Bead Array(TM) system [BDB].
Surface detection of CD69 and CD25 as well as intracytoplasmic detection
of IFNγ in CD4 + T-cells were both performed in TCRαβ + /CD4 + T-
LGL patients, to evaluate CMV and EBV-specific responses after longer
periods of stimulation [24-48h]. Results. Most patients [92%] were found
to be CMV- and EBV-seropositive. However, the percentage of patients
with CMV-specific CD4 + /TNFα + T-cells was significantly higher in
TCRαβ + /CD4 + T-LGL lymphocytosis [83%] than in either non-CD4 + /T-
LGL leukemias [17%] or non-LGL/CD4 + T-CLPD [22%]. Furthermore,
the former cases produced larger amounts of both IFNγ [p