BACKGROUND. Although various clinical observations suggested that myeloma c
ell growth might be modulated by the immune system, evidence supporting the
in situ immunogenicity of myeloma cells remains scarce. The authors reason
ed that if there is any specific T-cell/tumor cell interaction in myeloma,
it is most likely reflected in the T-cell population in the vicinity of the
tumor cells.
METHODS. The authors used a molecular method to compare the T-cell populati
ons in the vicinity of tumor cells with those in the peripheral blood in pa
tients with plasmacytomas and multiple myeloma.
RESULTS. Six patients were studied. When compared with the peripheral blood
from the corresponding patients, T cells in the vicinity of tumor cells in
five of the six patients showed significant contraction of the T-cell rece
ptor (TCR) VP repertoire. In addition to this, the T cells isolated from th
e sites of the tumor cells from four of these five patients also demonstrat
ed significant increase in the number of TCR VP gene families with restrict
ed number of CDR3 size peaks and loss of the normal CDR3 size gaussian dist
ribution pattern. These findings were observed in patients who experienced
recurrence after allogeneic stem cell transplantation and also in those who
had autologous stem cell transplant. They also were found in previously un
treated myeloma patients. In all six patients, distinct TCR VP recurring tr
anscripts indicative of a T-cell clonal expansion were found in the vicinit
y of the tumor cells and either absent or detected at only a low frequency
in the peripheral blood.
CONCLUSIONS, Our results provide evidence for an in situ local T-cell clona
l expansion in the vicinity of tumor cells and support the presence of spec
ific T-cell/tumor cell interaction in myeloma. (C) 2001 American Cancer Soc
iety.