Haematologica 2003 - Supplements

and clonal PC from MGUS, MM and PCL patients are
summarized in table 1.
Table 1: Immunophenotypic features of normal and clonal BM
plasma cells.
Normal MGUS
MM PCL
BM PC Normal Clonal PC
% of
CD56+
cells
% of
CD126+
cells
% of
CD95+
cells
% of
CD86+
cells
CD40
MFI
HLA-Iα
MFI
β2-
mmicroglobulin
MFI
CD38
MFI
8.0±12.
1
PC
9.0±6.9 59.1 ±44.8 78.5
±38.6
0±0 0±0 70.0 ±48.3 79.0
±41.9
0±0 7.1± 26.7 5.0 ±22.4 3.8
±19.6
54.7
±39.9
837.5±
190.4
4567.5±
1826.8
398.4±
275.4
8442.6±
1566.9
26.8± 20.7 100±0 84.2
±36.2
1154.4±
463.3
3855.8±
1670.7
675.1±
420.3
7423.0±
2399.0
952.0±
540.0
7080.3±
2031.9
1168.8±
986.8
5854.4±
2051.1
540.8±
308.1
5184.6±
2220.5
597.0±
744.2
4063.0±
1856.4
50.0
±57.7
50.0
±70.7
50.0
±57.7
100±0
605.2±
303.2
3904.6±
2525.1
209.1±
161.1
2387.4±
1119.1
Results expressed as mean±standard deviation; MFI: mean
fluorescence intensity.
In summary, our results confirm and extend previous
observations on the phenotypic differences existing between
normal and clonal PC from patients with MG. In addition, we
demonstrate that clonal PC from MGUS and from both MM and
PCL patients display clearly different phenotype which might
translate into different interactions between clonal PC and the
BM microenvironment in the distinct diagnosyic conditions.
055
Expression of the CD117 antigen (c-kit) on plasma cells
in monoclonal gammopathies
Maria Kraj, Ryszard Pogłód, Joanna Kopeć-Szlęzak,
Urszula Sokołowska, Barbara Kruk, Jolanta Woźniak
Institute of Haematology and Blood Transfusion, Warsaw, Poland.
We have previously shown the expression of c-kit, a receptor
with tyrosine kinase activity on plasma cells (PCs) of some
multiple myeloma (MM) patients (Kraj et.al. Immunology Letters
2000, 73, 123). The aim of the present study was analysis of
CD117 expression on monoclonal PCs in different
gammopathies. The study group consisted of 149 MM patients
(21 at stage I, 27-II, 101-III acc. to D.S. with monoclonal protein:
IgG-96, IgA-31, Bence Jones-16 and non-secretory 6), 10 plasma
cell leukemia (PCL), 7-M-IgM lymphoma plasmocyticum and 7
MGUS. The control group was 10 healthy subjects.
Immunophenotyping was done on freshly collected BM samples
using triple staining combination of CD138/CD117/CD38
monoclonal antibodies analysed by flow cytometry (Cytoron
Absolute and FACSCalibur-Becton Dickinson). PCs were
identified acc. to their strong reactivity for CD38, CD138 and
their typical light scatter distribution. Antigen expression
intensity was calculated as relative fluorescence intensity (RFI)
and for direct quantitative analysis the QuantiBRITE test (Becton
Dickinson) was applied. Mean channels of phycoerythrin
fluorescence were defined and antibody bounding capacity
(ABC) was then calculated using QuantiCALC software. In 49
patients (=33%) PCs showed CD117 expression. Out of all
nucleated BM cells the proportion of PCs with CD117 expression
ranged from 6 to 88%, mean 24,3±19%, median 18%. RFI values
ranged from 1,0 to 13 in particular patients (4,3±3,9, median 3,4)
and the number of CD117 binding sites (ABC) on MM plasma
cells ranged from 922 to 6217 (2343±1768, median 1714). A
correlation was found between RFI and ABC values (r=0,87). In
5 cases of MGUS PCs displayed CD-117 expression and in 2
cases did not.; this antigen was also expressed by leukemic cells
in 3 cases of PCL in an end phase of MM and in 1 case of
primary PCL. Only in one case of IgM lymphoma plasmocyticum
PCs expressed CD117 antigen. In 100 MM patients PCs did not
express CD117 and mean proportion of all BM cells with CD117
expression was 3,1±1,9%, median 2,9%. Normal PCs do not
express CD117. In BM of healthy persons mean proportion of
CD117+ cells was 2,4±0,7%, median 1,8%. Morfological
analysis of BM smears revealed that the percentage of BM PCs in
patients with positivity for CD117 was 37,7±24%, median 38%
while a corresponding value in those with cells negative for
CD117 was 37,3±24%, median 30%. In patients with myeloma
CD117+ a correlation was found between proportion of CD117+
cells and percentage of PCs in BM smears (r=0,65). Conclusions:
In one third of MM patients malignant PCs express the c-kit.
Intensity of c-kit expression on PCs varies among particular c-kit
positive MM patients and differences in expression level may be
as big as many times. Monoclonal PCs in PCL, MGUS and IgM
lymphoma plasmocyticum also in some cases express c-kit.
056
Expression of Chemokine Receptors in Multiple
Myeloma and its Correlation with Clinical Status:
Preliminary Results
A. Alegre (1), C. Muñoz (2) , S. López-Giral (2) , A.
Granda(1), B. Aguado (1), S.Osorio (1), S. Nistal (1) ,R..
Córdoba (1), JM Fernández-Rañada (1)
Hematology Department(1) and Inmunology Department(2).
Hospital Universitario de la Princesa. Madrid- Spain
Introduction: The mechanisms that contribute to the multiple
myeloma cell recruitment to the bone marrow environment are
not well known. Some recent findings suggest that chemokines
could play a relevant role for this compartmentalization of MM
cells in the bone marrow.(1,2,3) Chemokines are molecules
related with cellular adhesion and migration. These molecules are
implicated in lymphocyte trafficking and homing. In this study
we evaluate the expression of chemokine receptors in a group of
MM patients and its relation with disease type and clinical status.
Patients and methods.Bone marrow aspirates from 12 patients
with multiple myeloma were studies for the expression of
chemokine receptors: CCR7, CXCR5 and CXCR4 . Such analysis
was performed by using standard flow cutometry with mAb
directed against CCR7, CXCR5 and CXCR4 on electronically
gated myelomatous cells, previously identified by staining with
anti-CD38, anti-CD45, anti-CD19 and anti-CD56mAb.
Results. Expression of chemokine receptors in the mentioned
patients are shown in the next table:
S113