Increased density of ecto 5' nucleotidase antigen on leukemic T cells from
patients with cutaneous T-cell lymphoma and adult T-cell leukemia/lymphoma
Y Fukunaga, SS Evans, M Yamamoto, Y Ueda, K Tamura, T Takakuwa, D Gebhard, J Allopenna, S Demaria and B Clarkson
Department of Pediatrics, Nippon Medical School Hospital, Tokyo, Japan.
Malignant CD4+ T cells in adult T-cell leukemia/lymphoma (ATL) and
cutaneous T-cell lymphoma (CTCL) express a number of cell surface molecules
that are upregulated on normal T cells activated by foreign antigen. In
this report we describe an interesting exception to the parallel phenotypic
features of activated T cells and malignant CD4+ T cells. A monoclonal
antibody (MoAb; termed 27.2) that was raised to HTLV-1+, CD4+25+ leukemic T
cells stained weakly 25% of peripheral T cells, including approximately 50%
of CD8+ T cells and 20% of CD4+ T cells. Flow cytometry analysis indicated
that the surface density of the 27.2 antigen was unchanged or diminished
when normal T cells were activated by antigen. However, 3/4 Sezary cases
and 4/8 cases of ATL had relatively high densities of the 27.2 antigen.
Immunoprecipitation and sodium dodecylsulfate polyacrylamide gel
electrophoresis of the NP- 40-solubilized membranes of surface-iodinated
ATL cells indicated that MoAb 27.2 reacted with a 75 Kd molecule. The size
and distribution of the 27.2 antigen on T cell subsets suggested that it
might be the enzyme ecto-5' nucleotidase (NT), a
phosphatidylinositol-linked enzyme that catalyzes dephosphorylation of
monophosphate nucleotides to their respective nucleosides. This was
confirmed by demonstrating that lymphocyte ecto-5'NT activity was blocked
partially and inhibited completely by preincubating cells with MoAb 27.2
for 1 hour at 4 degrees C and 24 hours at 37 degrees C, respectively. When
used with a second MoAb (27.1) to a novel T cell activation antigen found
on all CTCL and ATL leukemias examined, 27.2 was found to discriminate
between normal and leukemic T cells in two patients with ATL. These studies
suggest that ecto-5'NT has diagnostic value in T cell malignancies and may
be aberrantly expressed in some cases of ATL and CTCL.
Volume 74,
Issue 7,
pp. 2486-2492,
11/15/1989
Copyright © 1989 by The American Society of Hematology
