Supplementum 163 - Swiss Medical Weekly

17 S SWISS MED WKLY 2008;138(Suppl 163) · www.smw.ch
Free Communications 6 – SSAI / SGAI
84
Heterozygous hypomorphic STAT3 mutations in 4 Swiss patients
of 3 unrelated families with classic autosomal dominant hyper
IgE syndrome
B. Drexel 1 , E.D. Renner 2 , T.R. Torgerson 2 , R.A. Seger 1 , H.D. Ochs 2 ,
J. Reichenbach 1 . 1 University Children’s Hospital Zurich (Zurich, CH);
2 University of Washington School of Medicine and Children’s
Hospital (Seattle, USA)
Background: Hyper-immunoglobulin E syndrome (HIES) is an
autosomal dominant disorder characterized by a highly elevated
serum IgE, eczema, recurrent staphylococcal skin abscesses and
cyst-forming pneumonia, with disproportionately milder inflammatory
responses, referred to as cold abscesses, and skeletal abnormalities.
Therapy involves lifelong antibiotic and antimycotic prophylaxis, and
occasionally surgical abscess drainage. The molecular defect,
heterozygous mutations of STAT3 has recently been identified
Methods: We enrolled 4 patients from 3 unrelated families with the
classic symptoms of HIES and looked for mutations in the gene
encoding human signal transducer and activator of transcription 3
(STAT3) by sequence analysis.
Findings: We found hypomorphic heterozygous STAT3 mutations in
all four patients with HIES suggesting a dominant negative effect. We
identified a novel R335W mutation within the DNA-binding domain in
two related patients from Sri Lanka, and a V637M mutation in the
other two non-related Swiss patients. The V637M mutation is one of
the four known STAT3 hotspot mutations and is located within the
SH2 domain. There was no difference in the clinical phenotype
between patients with mutations in the DNA binding or SH2 domain.
Conclusion: For four decades the molecular basis of HIES has
remained elusive. Here we show that dominant-negative mutations in
the STAT3 gene result in classic multisystem HIES in four patients
followed in Switzerland. The identification of STAT3 as the major
causative gene of HIES will facilitate early and definitive diagnosis as
well as treatment, hopefully leading to the prevention of serious
infectious complications and sequelae.
85
Tumour antigen specific CD8+ T-cells from melanoma patients
exert strong ex-vivo cytolytic activity
Y. Mahnke1 , E. Devêvre2 , P. Baumgaertner2 , M. Matter3 , N. Rufer4 ,
P. Romero2 , D. Speiser2 . 1 NIH (Bethesda, USA); 2 Ludwig Institute
for Cancer Research (Lausanne, CH); 3 CHUV (Lausanne, CH);
(4)Multidisciplinary Oncology Center (Lausanne, CH)
Direct analysis of ex vivo cytotoxicity by tumor Ag-specific T-cells has
long been precluded, because standard laboratory methods are not
suited to analyze small numbers of T-cells available from PBMC and
tumor infiltrated lymph nodes (TILN) from cancer patients. Here we
applied the recently described LiveCount Assay which allows to
determine the cytotoxic function of small numbers of isolated T-cells.
We analyzed Melan-A/HLA-A2 tetramer+ CD8+ T-cells from eight
melanoma patients. Surprisingly, strong cytotoxic activity was exerted
by T-cells derived from TILN or PBMC isolated after peptide
vaccination. Contrary to previous reports showing that TILN produce
low to no tumor-specific responses in vitro, our results illustrate that
they can be quite effective if isolated from the tumor
microenvironment, and thus separated from suppressor and/or
regulatory cells that might be contained therein. T-cells isolated from
TILN showed a trend to display lower killing activity than those from
PBMC, though the difference was not significant. As expected,
concomitant measurement of specific lysis and degranulation
revealed that only a subset of the cells were responsible for the
observed strong cytotoxicity. A direct correlation was observed
between the proportion of CD107a+ T-cells that were potentially
involved in the killing activity and the frequency of Granzyme B+ Tcells
detected ex vivo, although not all Granzyme B+ cells
participated in the lytic activity. We conclude that tumor antigen
specific T-cells are highly functional outside of the tumor
microenvironment. Studies are underway to elucidate the factors that
repress the effectiveness of tumor-specific T-cells locally, and how to
promote activation and avoid inhibition of protective immune
mechanisms.
86
Depletion of B-cells by rituximab therapy improves atopic
eczema
D. Simon1 , S. Hösli2 , G. Kostylina2 , N. Yawalkar1 , H-U. Simon2 .
1 Inselspital (Berne, CH); 2 University of Berne (Berne, CH)
Background: Atopic eczema (AE) is a chronic inflammatory skin
disorder characterized by eczematous skin lesions, pruritus and
typical histopathological features. Although T cells play a key role,
B cells are also found in the dermal infiltrate. In 80% of AE patients,
elevated total and specific IgE levels can be detected. This study
aimed to investigate the effect of a monoclonal anti-CD20 antibody
therapy (rituximab) in AE.
Methods: Six patients (2 males; mean age 39 ± 7 years) with severe
AE received two applications of rituximab, each 1000 mg IV two
weeks apart. To evaluate the efficacy of rituximab, we monitored
clinical parameters (EASI, pruritus), total and specific IgE levels, and
skin histology. Inflammatory cells and cytokine expression in skin
lesions were assessed by immunofluorescence analysis before and
after therapy.
Results: All patients showed an improvement of their skin symptoms
within 4 to 8 weeks. The EASI significantly decreased (before therapy:
29.4 ± 4.3; week 8: 8.4 ± 3.6; p