Transcript Transplantation Immunology

Transplantation
Xiang Li, Urology Department
West China Hospital, Sichuan
University
Acknowlegement
To Dr. Lu Yiping and Dr. Wang jia
To other Colleagues working on
renal and liver transplantation
Transplantation
is a Dream?


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Dream of Paranoia
Dream of excellent surgeon who
wants to excel himself.
Dream of excellent scientist who
believe nothing is impossible.
Can you imagine?
Can you imagine?
Can you imagine?
Contents
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Basic concepts of transplantation
Clinical Organ transplantation
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Renal Transplantation, RT
Transplantation Immunology
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MHC and Tissue Matching
Graft Rejection
Immunosuppression
Definition of Transplantation
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Implantation of „non-self” tissue into the
body
the process of taking cells, tissues, or
organs called a graft (transplant), from one
part or individual and placing them into
another (usually different individual).
donor : the individual who provides the graft.
recipient or host: the individual who receives
the graft.
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Blood Transfusion
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First attempts were unsuccesful
(MISMATCH)
Discovery of blood groups (Red cell antigens)
A-B
Landsteiner 1900
 Rh Levine, Stetson 1939
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Succesful transfusion = Transplantation
Others: Bone, Tissue-engineering, etc
Transplantation
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Organ Transplantation
Classification of Renal Transplantation
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Auto-RT
Cadaveric
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Allograft RT
Living related
Living Donor
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Living unrelated
Xenograft RT (In experimental)
Transplantation History
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experimental kidney transplantation -1912
 Alexis Carel-Nobel prize
1935 human kidney transplant in Russia - rejection
P.B. Medawar (1945) skin grafts
 Self skin accepted
 Relative not accepted !  What is the
difference ?
  Immunologic mechanism
A. Mitchison (1950)
 Lymphocytes are responsible for rejection
Transplantation History
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Peter Gorer (~1935)
 Identification of 4 group of genes for RBC
Gorer and Gorge Snell (~1950)
 Group II antigens are responsible for rejection
  Major HistoCompatibility genes (HLA)
 Nobel prize 1980 George Snell
1954 Succesful kidney transplant between identical
twins in Boston – Peter Bent Brigham Hospital
 Joseph Murray 1991 Nobel prize
HISTORY OF THE RT
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1933
1954
1958
1959
First clinical RT (Voronov);
First long-term successful RT(Twin);
Discovery of HLA(Human Lym Antigen);
Radiation be used for immunosuppression;
1961 Azathioprine (Aza);
1962 Prednisolone; Tissue Matching;
1966 Cross-Matching;
Late 1960’ Preservation the Kidney>24hr ;
1972 First successful RT(LRD) in china;
1978 Clinical use of Cyclosporine(CsA).
Key factors for succesful
transplantation
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Knowledge of MHC haplotypes
Effective immunosuppression
Ability to identify and treat infections
Available donors
Applications of allografting transplantation
The importance of transplantation:
Clinical Organ Transplantation
Liver Transplantation
Renal Transplantation
LIVER TRANSPLANTATION
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Indication: End stage liver diseases
(ESLD)
Hepatic Disease to ESLD
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Congenital malfomation;
Congenital liver metabolic disorders;
Acute liver failure;
Chronic liver failure:
(1) Cirrhosis: Hepatitis B, Alcoholic;
(2) Parasites: Hydatid disease of liver, ect.
liver malignance
RENAL TRANSPLANTATION
END STAGE RENAL DISEASES (ESRD)
Definition:
(1) Various causes;
(2) Irreversible injury;
(3) Functional failure.
Morbidity
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Europe: 50/million;
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China:
90-100/million
TREATMENT OF ESRD
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DIALYSIS
Chronic Ambulatory Peritoneal Dialysis
(CAPD);
Hemodialysis (HD).
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KIDNEY TRANSPLANTATION
Renal Transplantation
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Renal transplantation is associated with as
survival benefit for patients with ESRD when
compared to dialysis;
Even marginal donor kidneys confer a significant
survival advantage over maintenance dialysis.
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The preferred therapy for most of the Pts with
ESRD;
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More cost- effective; Better survival; Better life
quality.
CONTRAINDICATION
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Active invasive infection;
Active malignance;
High probability of operative mortality;
Unsuitable anatomic situation for
technical success;
Severe psychological or financial
problem.
Pre-OP Selection
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ABO Blood Group: Compatible;
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Cytotoxicity Test:
Donor Lymphocyte
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Recipient Serum
Cross matching
Donor Lymphocyte
Donor Serum
Recipient Serum
Recipient’s Lymphocyte
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Mixed Lymphocyte Culture
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Tissue typing (HLA)
OPERATION
DONOR
(1) Living donor
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Nephrectomy via flank approach;
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Nephrectomy via Laparoscope.
(2) Cadaveric Donor
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Total midline incision;
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in situ flashing: Euro-collins/UW
solution;
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Bilateral radical nephrectomy.
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Low temperature preservation.
Potential Advantages of living versus
cadaveric kidney donor
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Better short-term result(about 95% versus
90 % 1-yr function);
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Better long-term results(half-life of 12-20
yr versus 8-9 yr);
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More consistent early function and easy of
management;
Potential Advantages of living versus
cadaveric kidney donor
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Avoidance of brain death stress;
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Minimal incidence of delayed graft
function;
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Avoidance of long wait for cadaveric
transplant;
Potential Advantages of living versus
cadaveric kidney donor
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Capacity of time transplantation for
medical and personal convenience;
Immunosuppressive regime may be less
aggressive;
Help relieve stress on national cadaver
donor supply;
Emotional gain to donor.
Potential disadvantages of live donation
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Psychological stress to donor and family;
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Inconvenience and risk of evaluation
process(i.e., intravenous contrast);
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Operative mortality(about 1 in 2000 Pts.);
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Major post operative complications
(about 2% of Pts.);
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Potential disadvantages of live donation
Minor postoperative complications(up to
50% of Pts.);
Long-term morbidity(possible mild hypertention and proteinuria);
Risk for traumatic injury to remaining
kidney;
Risk for unrecognized covert chronic renal
disease.
Recipient Operation
Extraperitoneally in
the contralateral
iliac fossa via
Gibson incision.
Why contralateral ?
RECIPIENT OPERATION
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Blood Vessel Anastomosis:
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Donor renal V
Recipient’sexternal iliac V
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Donor renal A
Recipient’s internal iliac A
Ureter Anastomosis:
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Donor ureter
Recipient’s bladder
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Anti-reflux anastomosis
Clinical phases of rejection
1.
Hyperacute rejection (minutes to hours)
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2.
3.
Accelerated rejection
Acute rejection (around 10 days to 30 days)
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4.
Preexisting antibodies to donor HLA antigens
Complement activation, macrophages
Cellular mechanism (CD4, CD8, NK,
Macrophages)
Chronic rejection (months to years !!)
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Mixed humoral and cellular mechanism
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CHRONIC REJECTION IS STILL HARD TO MANAGE !
IMMUNOSUPPRESSION
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Immunosuppresents play a very important role in organ transplantation;
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Immuosuppresents extremely increase
the effect and the survival rate of organ
transplantation;
IMMUNOSUPPRESSION
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Immunosuppresents are a double edged sword;
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the most important thing is to increase
their positive effects, and in the same
time decrease their side effects (i.e.,
organ toxicity, infection, tumors, ect.).
Diagnosis of rejection
Symptom/Sign
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fever;
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urinary output ;
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graft tenderness;
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graft size ;
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hypertension;
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myalgia/arthragia.
Laboratory Test
 Serum creatine, SCr;
 Urinary creatine, Ucr;
 Color doppler scan;
 radiorenogram;
 Ateriogram;
 Biopsy:
(1) Fine needle aspiration biopsy
(FNAB);
(2) Core needle biopsy(CNB).
Treatment of kidney rejection
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Hyperacute (Sometimes during the operation !)
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No therapy, usually results in graft failure – kidney should
be removed
Acute (Most frequently in the first 4 weeks)
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BIOPSY !
Increase immunosuppression
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Increase steroid dose
Increase cyclosporin (monitor serum level !)
ATG, ALG, OKT3
Chronic
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ACE inhibitors, prostacyclin analog drugs
Steroid, Imuran, Cellcept
Transplantation Immunology
Histocompatibility Antigens
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Major histocompatibility antigens
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MHC class I molecules :
almost all nucleated
cells
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MHC class II molecules :
APCs, endothelium
of renal arteries and glomeruli
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Minor histocompatibility antigens : HY molecule
Major histocompatibility antigens
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Human leukocytic Antigen
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HLA I.
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(α1, α2, β1, β2)
Gene-Code alleles: DP, DQ, DR loci
HLA III.
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Gene-Code alleles: A, B, C loci
HLA II.
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(α1, α2, α3, β2-microglobulin)
Gene-Code alleles: C4A, TNF, HSP70
MHC complex: Gene
Major histocompatibility antigens
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MHC loci are highly polymorphic
Many alternative alleles at a locus
The loci are closely linked to each other
A set of alleles is called a HAPLOTYPE
One inherites a haplotype from mother
and another from father
The alleles are codominantly expressed
Inheritance of MHC alleles
A/C
A/D
B/C
Mother
Father
A/B
C/D
B/D
A/R1
R2/C
R2/R1
Possible children of parents with HLA haplotype A/B and C/D
R1=C-D recombination
R2=A-B recombination
Induction of Immune Responses Against
Transplants
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alloantigens and xenoantigens : antigens
that serve as the targets of rejection
the antibodies and T cells that react against
these antigens are said to be alloreactive
and xenoreactive, respectively.
allorecognition
 direct
 indirect
Rejection
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Senzitization stage
Not needed in hyperacute reactions !
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Effector stage
 Alloantibodies: bind to endothelium,
activate the complement system, and
injure graft blood vessels
Rejection
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Effector stage (Mostly cellular mechanism)
 Alloreactive T cells : recruit and activate
macrophages
--->
DTH
response
delayed type hypersensitivity
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Alloreactive
CTLs:
CTL
mediated
cytotoxicity lyse graft endothelial and
parenchymal cells directly
ADCC
CD4, CD8 lymphocytes, NK cells, macrophages
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Rejection
From: Kuby: IMMUNOLOGY (fourth edition, 2000)
Tissue typing
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Microcytotoxicity assay
 Known antibody to WBCs of donor / recipient
 Complement mediated lysis if Ab present on cell
surface
Mixed lymphocyte culture (MLC)
 Irradiated donor lymphocytes (stimulants)
 Incubated with recipient lymphocytes
 3H Thymidin incorporatin measured
Flow cytometry cross typing
DNA analysis
 Genomic typing (very precise, many subtipes)
Hyperacute Rejection
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Occurs within minutes of transplantation
Pre-existing IgM (natural) antibodies against
 ABO blood group antigens
 less
well-characterized antigens in
xenograft
 alloantigen,
such as foreign MHC
molecules, or alloantigen expressed on
vasular endothelial cells
Hyperacute Graft Rejection
Acute Rejection
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Occurs
within
days
or
weeks
after
transplantation
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Acute vascular rejection
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Necrosis of cells of the graft blood vessels
(vasculitis)
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Mediated
by
IgG
antibodies
endothelial
cell
alloantigens
complement activation
against
and
Acute Rejection
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Acute cellular rejection
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Necrosis of parenchymal cells
with lymphocyte and macrophage
infiltrates
Effector mechanisms :
 CTLs
 Activated
macrophages
 Natural killer cells
Acute Cellular Rejection
Chronic Rejection
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Occurs over months or years
Fibrosis with loss of normal organ
structures
Wound healing following the cellular
necrosis
A form of chronic DTH or a response to
chronic ischemia caused by injury to
blood vessels
Prevention and Treatment of
Allograft Rejection1
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Immunosuppression
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drugs that inhibit or kill T
lymphocytes
toxins that kill proliferating T cells
antibodies that deplete or inhibit T
cells
anti-inflammatory agents
Prevention and Treatment of
Allograft Rejection2
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Reduce the immunogenicity of
allografts
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ABO blood group typing
HLA typing and matching
induce donor-specific tolerance
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blood transfusion
Graft-versus-host Disease (GVHD)
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Occurs in bone marrow recipients
Initiated by T cell recognition of host
alloantigens
The effector cells are less well defined :
NK cells, CD8+ CTLs, cytokines
Acute GVHD
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Epithelial cell necrosis :
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Skin
Liver
The gastrointestinal tract
Characterized by skin rash, jaundice
and diarrhea
Acute GVH
Immunosuppressive therapy 1.
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Allogenic transplantation always require
immunosuppressive therapy
Most of the drugs available are nonspecific
Common side effects of therapy:
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Infection
Cancer
Bone-marrow depression
Immunosuppression 2.
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Conventional drugs (1st phase)
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Steroids /Prednisone/ (0.1-10 mg / kg)
Azathioprine /Imuran/ (0.5-3 mg/ kg)
Cyclophosphamide
(0.5-20 mg/ kg)
Methotrexate
(0.1-0.3 mg/ kg)
Immunosuppression 3.
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New drugs (1):
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CYCLOSPORIN A
(=REVOLUTION !)
2-8 mg/ kg
FK506 tacrolimus /PROGRAF/
Sirolimus - rapamycin
Gusperimus - dezoxyspergualin
Effects of cyclosporins
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Receptor: cytoplasmic immunophillin
calcineurin blockage  NF-Atc
Rapamycin also binds to immunophillin, but
the complex does not block calcineurin, it
blocks proliferation in G1 phase.
Highly lymphocyte specific. IL-2 action is impaired.
T lymphocyte (Th) is blocked.
Immunosuppression 4.
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Purin antagonists
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IMURAN
CELLCEPT (micophenolate mofetil)
Mizoribin – bredinin
Pirimidin antagonists
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Sodium-brequinar (highly lymphocyte
specific)
Monoclonal antibodies
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OKT3 (Anti CD3 mAb)
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Anti-TAC (anti-IL2 receptor)
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CD3 T cells
Activated T lymphocytes
Anti-CD4
Anti-LFA1 + anti-ICAM-1 – experimental
Anti-cytokine (IL-2, TNFα, IFNγ)
Problems of Transplantation
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There are not enough organs
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At least 150,000 patients in industrially
developed countries badly need donor
organs and tissues
Every 14 minutes another name is added to
the national transplant waiting list.
About 16 people die because of the lack of
available organs for transplant each day.
Rejection:
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When the immune system of the host
detects foreign graft tissue, it launches an
attack, resulting in tissue rejection
Gene technology may as a solution
Gene technology offers the possibility to breed
the desired organs in animals.
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Lack of organs is no longer a problem
Gene
technology makes it possible to
humanize the bred organs - the immune
system identifies the organ as its own tissue.
Immune system rejection is prevented
From which animals are we able to
transplant organs
1. The Chimpanzee:
Its DNA sequence
differs from ours by
only 2%
2. The Baboon:
Its organs are too
small for a large
adult human
3. The Pig:
Surprisingly similar
to our anatomy and
physiology
Organ breeding:
•A transgenic animal carries a foreign
gene inserted into its genome.
•The transgenic animal shows the
specific characteristics which are
coded on the inserted gene
 A gene which is responsible for the
construction of a human organ
makes the organism produce the
organ additionally.
The insert of a foreign gene into an animal
I. DNA microinjection
The DNA is inserted into the cell
with a small syringe
II. Retrovirus gene transfer
The DNA is carried into a cell by
a virus.
Suppression of immune system rejection
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The genes which are responsible for the own
tissue not being rejected can be injected into
an animal embryo
the organs of which are then similar to the
ones of the human.
It is possible to humanize the bred organs by
making certain genetic modifications.
Then the organs are accepted by the
immune system.
Conclusion
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Transplantation provides us the means of
restoring the function of a nonfunctional
organ.
In the case of BMT it enables us to
administer such high doses of
chemotherapy that would destroy the BM
as well as the residual tumor.
A lot immunologic knowledge had to be
collected to understand what is happening.
Conclusion
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HLA typing and matching is essential for
allografting transplantation.
Effective immunosuppressive therapy
(Cyclosporin) revolutionised organ
transplantation.
The future is to transplant cells, that would
restore the function of the affected organ.
Gene therapy is growing, and will cause
another revolution like cyclosporin did in
the 1980s.
To seek what everybody has sought
To think what nobody has thought
Try your best, everything will be possible