Oral Presentations - Federation of Clinical Immunology Societies

S24 Abstracts
Massachusetts General Hospital, Boston, MA, Leigh Field,
Professor, Department of Medical Genetics, University of
British Columbia, Vancouver, BC, Canada, Flemming Pociot,
Professor, Steno Diabetes Center, Gentofte
Type 1 diabetes (T1D) is a complex disease believed to
result from interactions between multiple risk-conferring
genes and environmental factors. In order to further
investigate the genetic contribution to T1D we genotyped a
case–control material for 58,000 SNP and tested these for
association to disease. The first phase of the study comprised
of thorough quality tests of the data for issues such as sample
contamination, inbreeding, low genotyping rates, relatedness
and population stratification which led to samples being
excluded. SNPs were removed for failing HWE in controls, low
genotyping rate, differences in missing genotyping rates
between cases and controls and being non-polymorphic,
which contributed to significant false positive findings. After
ensuring the highest quality of the data-set the remaining
52,000 SNPs and 605 individuals were analysed using basic
allelic and model-based tests of association corrected for
multiple testing and using permutation with empirically
corrected p-values. Furthermore we performed genomewide
sliding-window haplotype tests and full pair-wise test
for epistasis across the genome. We also performed the same
analyses for markers in 12 linkage regions previously reported
in T1D. Every individual test confirmed the importance of the
HLA region on chromosome 6p21.3 for developing T1D. In
combination these tests point to other chromosomal regions
contributing to T1D susceptibility. The significant findings
will be followed up in a larger case–control material to
confirm these present results. In addition this study has
demonstrated the importance of high quality data for
avoiding false positive findings when performing association
analyses in complex diseases.
doi:10.1016/j.clim.2007.03.235
F.23 iNKT Cell Regulation of Type 1 Diabetes
Dalam Ly, PhD Candidate, Robarts Research Institute,
London, ON, Canada, Qing Sheng Mi, Research Associate,
Robarts Research Institute, London, ON, Canada, Shabbir
Hussain, Research Associate, Robarts Reseach Institute,
London, ON, Canada, Terry L. Delovitch, Professor, Robarts
Research Institute, London, ON, Canada, Steven A. Porcelli,
Professor, Albert Einstein College of Medicine, Bronx, NY
The pathogenesis of type 1 diabetes (T1D) in NOD mice is
mediated by numerical and functional deficiencies in both
CD4+CD25+FoxP3+ regulatory T cells (Tregs) and invariant
natural killer T (iNKT) cells. Previously, we reported that
protection of NOD mice from T1D can be achieved by
activation of iNKT cells upon treatment with a multi-dose agalactosylceramide
(a-GalCer) protocol that promotes preferential
IL-4 secretion by iNKT cells. Since activated Tregs
and iNKT cells are both self-reactive and protect NOD mice
from T1D, we investigated whether iNKT-Treg collaboration
is required for this protection. We recently reported that
while a-GalCer therapy does not alter the proliferation or
regulatory activity of Tregs, Treg activity is required for a-
GalCer induced protection from T1D. This requirement of
Treg/iNKT collaboration for iNKT-mediated protection from
T1D may not apply for the therapy of T1D provided by certain
analogs of a-GalCer. Of particular interest is C20:2, an a-
GalCer analog with a shortened (C20) acyl chain and two
unsaturated bonds. When compared to a-GalCer, C20:2 yields
significantly reduced IFN-g and enhanced IL-4 secretion by
iNKT cells. Interestingly, we found that Treg activity is not
required for C20:2 mediated protection from T1D by iNKT
cells. Thus, our current results indicate that a-GalCer and
C20:2 may differ in their requirement of Tregs for iNKT
mediated protection from T1D. Ongoing studies will address
the mechanism(s) that underlies this differential requirement
of Tregs for protection from T1D.
doi:10.1016/j.clim.2007.03.236
F.24 Absence of Beta Cells in Long-Term Type 1a
Diabetic Patients
Travis Still, Professional Research Assistant, Barbara Davis
Center, Aurora, CO, Sally Kent, Instructor, Brigham and
Women’s Hospital, Boston, MA, Alberto Pugliese, Diabetes
Research Institute, University of Miami, Miami, FL, Piero
Marchetti, Full Professor, Ospedale di Cisanello, Pisa, Italy,
Francesco Dotta, Full Professor, University of Siena, Siena,
Bernhard Hering, Full Professor, Diabetes Institute for
Immunology and Transplantation, Department of Surgery,
University of Minnesota, Minneapolis, MN, Norma Kenyon,
Full Professor, Diabetes Research Institute, Cell Transplant
Center, University of Miami, Miami, FL, Camillo Ricordi,
Full Professor, Diabetes Research Institute, Cell Transplant
Center, University of Miami, FL, Miami, FL, Roberto
Gianani, Assistant Professor, Barbara Davis Center For
Childhood Diabetes, Aurora, CT
A recent report indicates that residual beta cells can be
identified in the pancreas of long-term diabetic subjects by
insulin immunostaining and in a subset of individuals by
detection of C-peptide. We have analyzed pancreata from 20
normal controls and 4 long-term diabetic subjects (1.5, 5, 22
and 30 years post diagnosis) by immunohistochemistry for
both insulin and the beta cell specific marker VMAT-2. We
confirmed the beta cell specificity of VMAT-2 by triple
immunostaining with glucagon, somatostatin and VMAT-2 of
normal human pancreas.
In the pancreata from long-term diabetic subjects we did
not find any VMAT-2 or insulin positive cells. In contrast
abundant insulin (as expected) and VMAT-2 positive cells
were present in all 20 normal human pancreata, in one new
onset type 1a and in a type 2 diabetic patient. There was
significant heterogeneity of staining intensity for VMAT-2
amongst the normal control pancreata suggesting individual
variability in VMAT-2 islet expression. Furthermore, there
was also variability in VMAT-2 expression between different
areas within the same pancreas with a zonal distribution of
strongly stained islets. These data indicate that in subjects
with long-term type 1A diabetes, there are no residual beta
cells by immunohistochemistry. Further studies of a larger
series of patients are needed to establish whether beta cells
continue to be present in type 1a diabetic subjects. In