Bone marrow and peripheral blood dendritic cells from patients with multiple myeloma are phenotypically and functionally normal despite the detectionof Kaposi's sarcoma herpesvirus gene sequences
N. Raje et al., Bone marrow and peripheral blood dendritic cells from patients with multiple myeloma are phenotypically and functionally normal despite the detectionof Kaposi's sarcoma herpesvirus gene sequences, BLOOD, 93(5), 1999, pp. 1487-1495
Multiple myeloma (MM) cells express idiotypic proteins and other tumor-asso
ciated antigens which make them ideal targets for novel immunotherapeutic a
pproaches. However, recent reports show the presence of Kaposi's sarcoma he
rpesvirus (KSHV) gene sequences in bone marrow dendritic cells (BMDCs) in M
M, raising concerns regarding their antigen-presenting cell (APC) function.
In the present study, we sought to identity the ideal source of DCs from M
M patients for use in vaccination approaches. We compared the relative freq
uency, phenotype, and function of BMDCs or peripheral blood dendritic cells
(PBDCs) from MM patients versus normal donors. DCs were derived by culture
of mononuclear cells in the presence of granulocyte-macrophage colony-stim
ulating factor and interleukin-4. The yield as well as the pattern and inte
nsity of Ag (HLA-DR, CD40, CD54, CD80, and CD86) expression were equivalent
on DCs from BM or PB of MM patients versus normal donors. Comparison of PB
DCs versus BMDCs showed higher surface expression of HLA-DR (P = .01), CD86
(P = .0003), and CD14 (P = .04) on PBDCs. APC function, assessed using an
allogeneic mixed lymphocyte reaction (MLR), demonstrated equivalent T-cell
proliferation triggered by MM versus normal DCs. Moreover, no differences i
n APC function were noted in BMDCs compared with PBDCs. polymerase chain re
action (PCR) analysis of genomic DNA from both MM patient and normal donor
DCs for the 233-bp KSHV gene sequence (KS330(233)) was negative, but nested
PCR to yield a final product of 186 bp internal to KS330(233) was positive
in 16 of 18 (88.8%) MM BMDCs, 3 of 8 (37.5%) normal BMDCs, 1 of 5 (20%) MM
PBDCs, and 2 of 6 (33.3%) normal donor PBDCs. Sequencing of 4 MM patient P
CR products showed 96% to 98% homology to the published KSHV gene sequence,
with patient specific mutations ruling out PCR artifacts or contamination.
In addition, KHSV-specific viral cyclin D (open reading frame [ORF] 72) wa
s amplified in 2 of 5 MM BMDCs, with sequencing of the ORF 72 amplicon reve
aling 91% and 92% homology to the KSHV viral cyclin a sequence. These seque
nces again demonstrated patient specific mutations, ruling out contaminatio
n. Therefore, our studies show that PB appears to be the preferred source o
f DCs for use in vaccination strategies due to the ready accessibility and
phenotypic profile of PBDCs, as well as the comparable APC function and low
er detection rate of KSHV gene sequences compared with BMDCs. Whether activ
e KSHV infection is present and important in the pathophysiology of MM rema
ins unclear; however our study shows that MMDCs remain functional despite t
he detection of KSHV gene sequences. (C) 1999 by The American Society of He
matology.