PowerPointPrsentation

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Novel non-HLA antibodies and rejection Duska
Dragun Nephrology, Charité Campus Mitte, Humboldt
University Berlin
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Antibody mediated acute rejection

• The issue is not trivial, humoral rejection
  causes 30 of acute rejections and 10 of graft
  failures
• Pathogenesis
• donor-specific antibodies against HLA class I and
  class antigens (C4d)
• non-HLA antibodies against unknown targets

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Subpopulation of patients with unclear rejection

• severe pathology endarteritis or fibrinoid
  necrosis

• 16/16 cases negative for HLA class I and class
  II DSA

• no hereditary or autoimmune thrombophilia

• negative serology for autoimmune disorders

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Inferior survival in patients with non-HLA
antibody rejection
Dragun, D. et al. N Engl J Med 2005352558-569
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Demographic data
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Clinical manifestations and biopsies
Histology C4d positive
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Our index case
50-years old female recipient of the first, zero
mismatch full-house kidney transplant with
primary graft function (creatinine 1.0 mg/dl at
postoperative day 3) develops refractory vascular
rejection with BP 240/160 mm Hg.
Autoimmune serology is negative CMV negative No
hereditary thrombophilia.
Why is this patient rejecting?
Interesting detail from patientsmedical history
During my pregnancy, 25 years ago, I also had
very high blood pressure and I almost lost my
baby.
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J Clin Invest 103 945-952, 1999
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Bioassay for Ang II Typ1Rezeptor (AT1R)
agonistic antibodies
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Bioassay results for Ang II type 1receptor
(AT1R) activity
C4d
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IgG activate Angiotensin II Type 1 Receptor
Increase in BPM
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AT1R agonistic activity in transplant
nephrectomies
Increase in BPM
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Losartan PPH improve graft survival in AT1R-AA
patients
Dragun, D. et al. N Engl J Med 2005352558-569
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Influence of losartan PPH on AT1R activity
Dragun, D. et al. N Engl J Med 2005352558-569
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AT1R IgG subclass activity
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Binding sites of AT1R activating IgG1 and IgG3
Ang II type 1 receptor
Ingelfinger, J. R. N Engl J Med 2005352617-619
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Incidence of AT1R-AA positive rejection
279 kidney transplantations in 4.5 years(Jan 1st
2000 July 31st 2004)
119 rejection episodes in 83 patients
23 refractory to steroids (19.3 of all
rejections)
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Incidence of AT1R-AA positive rejection
23 refractory to steroids (19.3 of all
rejections)
9 episodes HLA-DSA pos39.1 of refract.
rejections
10 episodes AT1R-AA pos43.5 of refract.
rejections
4 HLA-DSA neg/AT1R-AA neg
7.6 of all rejections
8.4 of all rejections
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Interdisciplinary bedside to bench approach
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ERK ½ phosphorylation
coronary endothelial cells
coronary VSMC
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NF-kB
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(No Transcript)
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Cell promoter transfection experiments
Tissue factor is a target of NF-kB and AP-1
C4d
AT1R-AA
Mutant promoter
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Tissue Factor expression in patients biopsies
TF vor PPH Losartan
TF nach PPH Losartan
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Kochspostulate study to investigate pathogenic
role of AT1R-AA in transplant vascular pathology
passive transfer of human IgG with AT1R agonistic
activity
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Orthotopic life-supporting functional NTx rat
model
Control IgG
Lew recipient
F344 donor
AT1-AA
7 d. pre NTx
7 d. post NTx
c
allograft morphology
telemetry device implant.
NTx, osmotic mini-pump
Telemetry follow-up
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AT1R-AA induce vascular rejection
AT1R-AA human IgG
AT1R-AA- human IgG
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Colocalization of AT1R-AA (human IgG) with AT1R
AT1R-AA human IgG
AT1R-AA- human IgG
AT1R
human IgG
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AT1R-AA induce hypertension
Dragun, D. et al. N Engl J Med 2005352558-569
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Do AT1R-AA fulfill Kochs postulates?

• The agent (AT1-AA) should be present in all cases
  but not in controls
• The agent (AT1-AA) must be isolated from the
  cases and studied in cells
• The agent (AT1-AA) transferred into a healthy
  laboratory animal, should cause the disease
• The agent should be re-isolated from the
  experimental disease

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Putative mechanism of action of AT1R-AA
Apoptosis? Permeability?
Mø
CTL
AT1R-AA
AT1R-AA
AT1R-AA
AT1R
AT1R
AT1R
ECs
MAPKs (Erk 1/2)
AT1R-AA
AT1R-AA
AT1R-AA
AT1R
AT1R
MAPKs (Erk 1/2) NF-kB, AP-1
RANTES
VSMCs
TF
MCP-1
TF
Thrombotic Angiopathy!
Effector cell infiltration!
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AT1R-AA collaborators
Max-Delbrück-Centre Berlin Gerd
Wallukat Nephrology, Charité Campus Buch Ralf
Dechend Dominik N. Müller Ralph Plehm Jan Hinrich
Bräsen Friedrich C. Luft Pharmacology, Charité
Campus Mitte Ulrich Kintscher Thomas Unger
Nephrology, Charité Campus Mitte Diana
Eckert Melina Nieminen-Kelhä Lutz
Fritsche Klemens Budde Hans-H. Neumayer HLA
Laboratory Charité Constanze Schönemann Pathology
, Charité Campus Mitte Birgit Rudolph CNRS,
Strasbourg Johan Hoebeke