96. Jahrestagung der Deutschen Gesellschaft für Pathologie e. V ...

Abstracts
ray-based expression profiling in 468 tissue samples from 25 healthy organs
from more than 210 patients.
Results. We found that CD317 protein was expressed to varying degrees
in all organs tested and detected in a number of specialized cell types,
including hepatocytes, pneumocytes, ducts of major salivary glands,
pancreas and kidney, Paneth cells, epithelia, Leydig cells, plasma cells,
bone marrow stromal cells, monocytes, and vascular endothelium. Although
many of these cell types are in vivo targets for pathogenic viruses,
restriction by CD317 or virus-encoded antagonists has been documented
in only some of them. Limited cell type-dependent co-expression
of CD317 with the IFN biomarker MxA in vivo and lack of responsive
stimulation in organ explants suggest that interferons may only partially
regulate CD317.
Conclusions. This in vivo expression profiling sheds light on the biology
and species-specificity of CD317, identifies multiple thus far unknown
interaction sites of viruses with this restriction factor, and refutes the
concept of its restricted constitutive expression and primary IFN inducibility.
CD317’s widespread expression calls into question its suitability as
a target for immunotherapy.
DO-047
Frequent detection of the Merkel cell polyomavirus in B-lymphocytes:
implications for non-Hodgkin lymphomagenesis?
D . Rennspiess1 , A . Haugg1 , J . Beckervordersandforth1 , A .K . Kurz2 , R . Plusquin1 ,
G . Cathomas3 , C . Wendtner4 , E .-J . Speel1 , H . Kvasnicka5 , A . zur Hausen1 1Maastricht University Medical Center, Department of Pathology, Maastricht,
Netherlands, 2University Hospital Aachen, Department of Internal
Medicine IV, Aachen, 3Kantonsspital Liestal, Institute of Pathology, Switzerland,
4University Hospital Cologne, Department I of Internal Medicine, Köln,
5University Hospital Frankfurt, Institute of Pathology, Frankfurt
Aims. The recent discovery of the Merkel cell polyomavirus (MCPyV)
in Merkel cell carcinomas (MCC) also had an important impact on the
well established epidemiological association of CLL/SLL with MCC. We
have recently demonstrated the presence of MCPyV DNA in highly purified
CD5+/CD19+ CLL cells. Meanwhile, the presence of MCPyV DNA
in CLL/SLL cells has been independently demonstrated by two other
groups reporting MCPyV-DNA in approx. 21–33%. In addition, we were
able to demonstrate MCPyV integration by fluorescence in situ hybridisation
(FISH). Here we extended our analyses to different types of non
Hodgkin lymphomas (NHL) as well as to non neoplastic reactive follicular
lymph nodes for the presence of MCPyV by FISH and/or MCPyV
DNA PCR.
Methods. DNA PCR was carried out on 8 formalin-fixed and paraffin
embedded SLL cases and 1 DLBCL case and on 39 reactive lymph nodes
as previously described. On these and on a tissue microarray (TMA) containing
CLL/SLL (n=43), MZL (n=44), FL (n=40), MALT (n=47), DLBCL
(n=32), and T cell lymphomas (n=19) MCPyV FISH was performed.
Results. MCPyV DNA was detected by PCR in 6 of the 8 SLL cases and in
13 of the 39 reactive lymph nodes. By MCPyV FISH sharply punctate dots
– compatible with viral integration – were identified in 29% (n=15/51) of
CLLs, in 9% (n=4/45) of MZL, in 35% (n=14/40) of FL, in 15% (n=7/47)
of MALT, and in 18% (n=6/32) of DLBCL. All T cell lymphomas were
MCPyV negative. Of interest, small clusters of MCPyV DNA positive B
cells were detected in the follicle centres of the reactive lymph nodes.
These hybridization signals were punctate and multiple, and some of
them revealed a diffuse hybridization pattern.
Conclusions. MCPyV FISH confirms our previous data on the integrated
presence of MCPyV in CLL. Other B-cell NHL might be associated with
the presence of integrated MCPyV. The finding of small clusters of follicular
B-cells harbouring integrated MCPyV DNA is suggestive for an
early and rather common MCPyV infection of premature B-cells which
normally – during the process of follicular B-cell maturation – are eliminated.
MCPyV-positive follicular B-cells which are not eliminated,
thus not recognised as “foreign”, are likely to be the reservoir of cells
26 | Der Pathologe · Supplement 1 · 2012
which during a long-term transformation process by an accumulation of
oncogenic mutations or deletions turn into a NHL cell. Functional studies
concerning MCPyV and lymphomagenesis are ongoing in order to
elucidate a possibly underlying etiopathogenic role for MCPyV in NHL
lymphomagenesis.
DO-048
The majority of immunohistochemically BCL2 negative FL grade I/
II carry a t(14;18) with mutations in exon 1 of the BCL2 gene and
can be identified with the BCL2 E17 antibody
I . Bonzheim1 , R . Baumann1 , P . Adam1 , F . Fend1 , L . Quintanilla-Martinez 1
1University Hospital Tübingen, Institute of Pathology and Neuropathology,
Tübingen
Aims. Follicular lymphoma (FL) is characterized by the translocation
t(14;18)(q32;q21) resulting in constitutional overexpression of the antiapoptotic
protein BCL2. However, 10–15% of FL grade I/II remain negative
in the immunohistochemical (IHC) staining for BCL2. The aims of
this study were: 1) to investigate the incidence of IHC BCL2 negative FL
grade I/II diagnosed at our institution, 2) to analyze BCL2 IHC negative
FL with the alternative BCL2 antibody (clone E17) and perform FISH
analysis for the t(14;18), and 3) to elucidate the molecular mechanism of
immunohistochemical BCL2 negativity.
Methods. FL grade I/II diagnosed between 01/2005 and 08/2011 at the
Institute of Pathology of the University of Tübingen were included in
the study. All cases were stained with the standard BCL2 antibody (clone
100D5; DCS). BCL2 negative cases were subsequently stained with the
BCL2 antibody, clone E17 (Zytomed) and analyzed by FISH using a BCL2
break-apart probe (LSI BCL2 BAP, Vysis). Exon 1 of the BCL2 gene, where
the epitope of the standard BCL2 antibody resides, was amplified and
sequenced.
Results. 23 (9.6%) of the 240 identified cases of FL grade I/II were negative
with the standard BCL2 antibody. Of these, 13 cases (57%) were
positive for the E17 antibody and 10 cases (43%) remained negative. All
E17 positive cases showed a BCL2 break by FISH analysis, indicative of
a t(14;18), whereas the E17 negative cases lacked BCL2 alterations. Two
of the E17 negative cases carried a BCL6/IGH translocation. Sequencing
of BCL2 exon 1 revealed missense point mutations resulting in amino
acid substitutions in all 9 analyzable E17-positive cases, with a hot spot
around codon 144.
Conclusions. The incidence of immunohistochemically BCL2-negative
FL grade I/II in our series is comparable to published data. The E17 antibody
reveals the presence of BCL2 protein undetectable with the standard
antibody due to exon 1 missense mutations in the majority of BCL2
“negative” FL grade I/II and correlates with the presence of the t(14;18).
The molecular pathogenesis of the BCL2 (E17)- and t(14;18) negative FL
grade I/II remains to be determined.
DO-049
Follicular lymphoma with prominent mantle zones – a FICTION
analysis
P . Kosmidis1 , P . Adam1 , I . Bonzheim1 , L . Quintanilla-Fend1 , P . Bauer2 ,
M . Scharpf1 , T . Henopp1 , F . Fend1 1Eberhard-Karls-University, Institute of Pathology and Neuropathology, Tübingen,
2Eberhard-Karls-University, Institute of Human Genetics, Tübingen
Aims. Follicular lymphoma (FL) is characterized by the recurrent translocation
t(14;18), resulting in BCL2 protein overexpression. Most cases
show an indolent clinical course, which in part may be a result of the
influence of the complex tumor microenvironment of FL. Involvement
of different lymph node compartments may indicate a biologically more
advanced lymphoma, whereas restriction of neoplastic cells to germinal
centers might represent earlier disease stages. We have therefore exami-