Haematologica 2003 - Supplements

059
VEGF receptor expresion in Multiple Myeloma.
Manuel Callís, Cristina Barrenetxea, Mª Carmen Ruiz-
Marcellán
Hospital Universitario Valle Hebrón. Barcelona.
VEGF is peptide with a potent angiogenic affect, as well as
mitogenic activity and anti-apoptotic effect, through cytokine
release.
Results: We investigated thirteen patients in different disease’s
stages. Six cases were performed in marrow clots, seven in
biopsy cilinders, and in a single occasion an aspirate’smear was
carried out, resulting in a negative report.
Their relationship to Thalidomide therapy could not be pursued,
since only two patients received it, one was not evaluable because
early drug intolerance, and the other, who had a long lasting
response, could not be evaluated since her baseline marrow smear
was not assesable.
The greatest positivity was found at diagnosis, being markedly
intense in 4 out of 7 cases, but all of them displaying expression.
On the other hand no receptors were detectable in 2 out of three
responding cases.
Conclusions : Cytokine induction is playing a more relevant role
in the biology of Multiple Myeloma.
VEGF expression is very common, particularly at disease
presentation, and consequently early phase therapy with VEGF
inhibitors seems more then appropiate.
From the technical standpoint, the marrow clot is as good as the
cylinder, and possibly more feasable.
060
BCL-xl expression in Multiple Myeloma
S. Hovenga, S.D.P.W.M. Peeters, S. Rosati, E.Vellenga
Department of Hematology and Pathology, University Hospital
Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
Multiple Myeloma (MM) is characterized by a malignant
proliferation of monoclonal plasma cells in the bone marrow that
are highly chemotherapy resistant suggesting the involvement of
anti-apoptotic proteins. Subsequently we studied the expression
of Bcl-xl, a downstream target of the transcription factor STAT3
that is controlled by IL-6. Fourty MM patients were studied
upfront treatment and 25 MM patients at time of relapse. The
results were compared with the Bcl-xl expression in normal bone
marrow plasma cells. In addition the results were correlated with
the level of CRP, the microvessel density (MVD) and clinical
outcome. Upfront treatment 78% of the patients demonstrated a
normal Bcl-xl staining compared to normal plasma cells, whereas
22% of the patients demonstrated an elevated expression. In
addition 20% of the patients demonstrated two populations of
plasma cells with normal and elevated Bcl-xl expression. At time
of relapse no change in Bcl-xl expression was observed compared
to upfront treatment. No distinct correlation was observed
between the level of CRP and the Bcl-xl expression suggesting an
IL-6 independent effect. In addition no significant correlation was
observed with the MVD which was significantly increased
compared to normal bone marrow biopsy specimens (median 70,
range 30-255 versus median 48, range 33-77, P = 0·019). Finally
it was shown that the subgroup of patients with an elevated Bcl-xl
expression could not be distinguished based on the results of
overall- and event free- survival. In summary these data indicate
that an elevated Bcl-xl expression can be observed in a subgroup
of MM patients which is likely IL-6 independent and will
contribute to chemotherapy resistance of the malignant plasma
cells.
061
Detection and Quantification of Free Light Chains in
Myeloma Cell Culture Supernatant
Morten Salomo, Lars Bo Nielsen, Peter Gimsing
Dept. of Hematology and Clinical Biochemistry, Rigshospitalet
Production of paraproteins is a hallmark of multiple myeloma.
The amount of paraproteins in plasma and urine is used to stage
and monitor the myeloma, but the monoclonal immunoglobulins
and light chains also have direct effects in myeloma nephropathy,
immunoparesis, and amyloidosis. Thus, the measurement of
immunoglobulin synthesis is of considerable interest. In this
study, we have evaluated a new approach to detect and quantify
light chain production in multiple myeloma cell lines in vitro.
Initially, the myeloma immunophenotype of the two myeloma
cell lines JJN-3 and RPMI (kappa and lambda light chains,
respectively) was ascertained with flowcytometry. No
cytoplasmatic heavy chain expression was detectable.
Accordingly, culture supernatants of both cell lines were negative
for IgG and IgA in a turbidimetric analysis. While standard serum
electrophoresis failed to detect a monoclonal peak due to low
amounts, immunofixation revealed monoclonal kappa (JJN-3)
and lambda (RPMI) light chains in the culture supernatants.
Moreover, using a newly developed HRAGE method for
detection of unconcentrated urinary BJP (Salomo,M., Gimsing,P.,
& Nielsen,L.B. (2002) Simple method for quantification of Bence
Jones proteins. Clin.Chem., 48, 2202-2207) we were able to
visualize and quantify the free light chains in the culture
supernatant of RPMI cells. Thus, immunofixation and a sensitive
high resolution agarose gel electrophoresis enable the detection
and quantification of free light chain synthesis by myeloma cell
lines. These techniques will be valuable tools in assessments of
the impact of therapeutic agents on immunoglobulin synthesis.
062
Novel effects of β2-microglobulin on the immune
system
Qing Yi, Jin Xie, Ying Wang, John Freeman, Bart Barlogie.
Myeloma Institute for Research and Therapy, University of
Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
ß2-Microglobulin (2M) is the invariant chain of the major
histocompatibility complex (MHC) class-I molecules and free
ß2M (usually 10 µg/ml) of ß2M to the culture impaired in
vitro generation of DCs; ß2M reduced the yield of DCs, inhibited
the upregulation of their surface expression of HLA-ABC, CD1a,
S115