66
ICCS 2011
P30
T Cell Receptor Gene Rearrangement in Flow-
Sorted Natural Killer (NK) Cells in Chronic
Lymphoproliferative Disorders of NK cells
Jason M. Schallheim, Ying Pei, Guang Fan, Rita M.
Braziel
Oregon Health Science University, Portland, OR, USA
Chronic lymphoproliferative disorders of NK-cells (NK-
CLDs) are heterogeneous disorders characterized
by persistently increased peripheral blood NK-cells.
Rare cases of NK-CLD have shown clonal T-cell
receptor (TCR) gene rearrangements, but specifc
cell subpopulations have not been analyzed. Here we
report two cases of NK-CLD with TCR clonality. Case
1 is an 81-year-old female with normal peripheral
blood lymphocytes (3.18 x 10
3
/µL). Flow cytometry
identifed increased NK-cells (24% CD2+, CD3-,
CD16+, CD56+), and also increased NK/T-cells (13%
CD2+, CD3+, CD16+, CD56+). Different TCR clones
were identifed in the fow-sorted NK-cells (CD3-/
CD56+) and the NK/T-cells (CD3+/CD56+). The T-cell
population (CD3+/CD56-) was polyclonal. Case 2 is
a 49-year-old female with persistent lymphocytosis
(9.47 x 10
3
/µL). Flow cytometry identifed increased
abnormal NK-cells (40% CD2+, CD3-, CD16+,
CD56-, CD57+, CD94+ and CD158a+/CD158c+ killer
cell immunoglobulin-like receptor antigens). T-cells
(59%) showed no evidence of abnormal antigenic
expression except a decreased CD4:CD8 ratio of
0.8:1. TCR clonality was identifed in the non-sorted
peripheral blood. Additional molecular analysis of
fow-sorted NK-cells and T-cells is pending, but the
lack of aberrant antigen expression in the T-cell
population suggests that the clonality is likely in the
abnormal NK-cells. In summary, there is increasing
evidence that NK-cells in some NK-CLDs harbor
clonal TCR gene rearrangements. Molecular analysis
of fow-sorted subpopulations of NK and T-cells in
NK-CLD may provide important new insights into the
complex relationship of these cells. In addition, TCR
clonality may be useful in a subset of cases as a
diagnostic marker to differentiate NK-cell malignancy
from reactive NK-lymphocytosis.
POSTER ABSTRACTS