Oral Presentations - Federation of Clinical Immunology Societies

S22 Abstracts
correlated with the observed reduced fraction of CD4+CD25+ T
cells in the huFlt3-L-treated mice. Translation of these data
suggests that huFlt3-L might only be a useful therapeutic agent
for T1D patients with a demonstrated DC (subset) defect.
doi:10.1016/j.clim.2007.03.229
F.17 The BDC 12-4.1 TCR Alpha Chain is Sufficient to
Generate Anti-Insulin Autoantibodies; α+β Chain
for Insulitis
Masakazu Kobayashi, Fellow, Barbara Davis Center, Aurora,
CO, Jean Jasinski, Graduate Student, Barbara Davis Center,
Aurora, CO, Maki Nakayama, Fellow, Barbara Davis Center,
Aurora, CO, Dongmei Miao, PRA, Barbara Davis Center,
Aurora, CO, Marcella Li, PRA, Barbara Davis Center, Aurora,
CO, Liping Yu, PRA, Barbara Davis Center, Aurora, CO, Edwin
Liu, Associate Professor, Barbara Davis Center, Aurora, CO,
George Eisenbarth, PI, Barbara Davis Center, Aurora, CO
There is a marked T cell receptor (TCR) α chain restriction
of T cell clones that target the insulin peptide B:9–23 in NOD
mice. We are pursuing the hypothesis that this non-stringent
TCR with conserved V α (TRAV5D-4*04) and J α (TRAJ53*01)
chains (not N of α or β chain) underlies insulin autoimmunity
and diabetes propensity. To test this hypothesis, we created
TCR transgenic mice bearing only the BDC12-4.1 α chain,
combined with C α knockout. Mice with the BDC 12-4.1 α
chain, regardless of the presence or absence of the BDC 12-4.1
TCR β chain, produced insulin autoantibodies, whereas mice
bearing BDC 12-4.1 TCR β chain but not α chain did not. In
contrast to production of insulin autoantibodies, we found
insulitis in only mice with both 12-4.1 α and β chains (C α TCR
knockout). Our results indicate that provision of only the
BDC12-4.1 α chain results in expression of insulin autoantibodies
(with endogenous β chains) and the ββ chain
contributes to development of insulitis. At present we are
producing mice with BDC12-4.1 α chain (Cα knockout) and β
chain from anti-ovalbumin DO.11.10 T cell clone, which also
produce insulin autoantibodies, but we need to combine Vβ
knockout. A simple TCR motif and single insulin peptide may
be essential for anti-insulin/anti-islet autoimmunity of the
NOD mouse.
doi:10.1016/j.clim.2007.03.230
F.18 HLA-DR3/4 Heterozygosity is a Risk Factor for
Autoantibody Conversion and Type 1 Diabetes
Recurrence After Simultaneous Pancreas-Kidney
Transplantation
Stavros Diamantopoulos, Fellow, Diabetes Research
Institute and Department of Pediatrics, University of
Miami, Miami, FL, Gloria Allende, Research Associate,
Diabetes Research Institute, Miller School of Medicine,
University of Miami, Miami, FL, George W. Burke, Professor
and Co-Director, Division of Transplantation, Department of
Surgery, Miller School of Medicine, University of Miami,
Miami, FL, Gaetano Ciancio, Professor and Director of
Transplant Education, Department of Surgery, Miller School
of Medicine, University of Miami, Miami, FL, Alberto
Pugliese, Director, Division of Immunogenetics, Diabetes
Research Institute, Miller School of Medicine, University of
Miami, Miami, FL
We studied 252 patients with type 1 diabetes (T1D) who
received a simultaneous pancreas-kidney (SPK) transplant.
Patients were tested for GAD and IA-2 autoantibodies, wellknown
T1D risk markers. One-hundred-thirty-one patients (52%)
remained GAD/IA-2 autoantibody-negative; 44 (17.4%) converted
to GAD and/or IA-2 positivity while 77 (30.6%) had
autoantibodies before the transplant that persisted on followup.
We then analyzed recipients' HLA-DR types in relation to
autoantibody conversion and T1D recurrence (T1DR) on followup
(range 0.08-15.9 years, mean 5.6+3.6 years) in the 175
patients who remained autoantibody-negative or converted.
Twenty of 44 (45%) converters carried the HLA-DR3/4 genotype
vs. 22/131 (17%) autoantibody-negative patients (p=0.0001,
OR=4.5). Conversion occurred in 20/42 (47.6%) patients with the
HLA-DR3/4 genotype vs. 24/133 (18%) patients without it
(p=0.0001, Kaplan-Meier lifetable analysis; p=0.0002. OR=4.2,
Chi-square). The non-heterozygotes included 53 patients with
HLA-DR3 alone, 53 with HLA-DR4 alone and 23 with neither
types. Excluding patients that did not carry HLA-DR3 or HLA-
DR4, HLA-DR3/4 heterozygotes converted more often than
patients carrying HLA-DR3 or HLA-DR4 alone (p=0.0001, Kaplan-
Meier lifetable analysis; p=0.0002, OR=4.4, Chi-square). Ten
patients developed T1DR on follow-up, of whom 60% were HLA-
DR3/4 heterozygotes: 6/42 (14%) patients with the HLA-DR3/4
genotype developed T1DR vs. 4/133 (3%) without it (p=0.01,
Kaplan-Meier lifetables analysis; p=0.01, OR=5.37, Chi-square).
Our data suggest that the HLA-DR3/4 genotype is a risk factor for
autoantibody conversion and for the development of disease
recurrence in SPK recipients. Patients with this genotype
represent a high-risk group that should be monitored for
markers of recurrent autoimmunity.
doi:10.1016/j.clim.2007.03.231
F.19 Kinetics of Regulatory T Cells Upon Specific
Diabetogeneic Activation in a Group of High Risk
Relatives of Type 1 Diabetes Mellitus Patients in
Comparison with Healthy Controls
Zuzana Vrabelova, PhD Student, University Hospital Motol,
Children’s Neurology Department, Prague, Zuzana
Hladikova, Statist, Czech Agriculture University,
Department of Statistics, Prague, Katerina Stechova, Lab
Chief, University Hospital Motol, Pediatric Department,
Prague, Kristyna Bohmova, PhD Student, University Hospital
Motol, Pediatric Department, Prague, Jaroslav Michalek,
Head of Cell Immunotherapy Center, Masaryk University Br
England Cell Immunotherapy Center, England
Abnormalities in CD4+CD25+ regulatory Tcells (Tregs) may
contribute to type 1 diabetes (T1D) development. We have
studied immunoregulatory populations of CD4+CD25+ T cells
in a group of high-risk relatives of T1D patients. We have
evaluated kinetics of Tregs (using specific markers CD127−
and Foxp3+) after specific stimulation with diabetogenic
autoantigens in 11 high-risk (according to HLA-linked T1D
genetic risk) relatives of T1D patients and 14 healthy