Transplantation - PowerPoint PPT Presentation

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?

• 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?

• Basic concepts of transplantation
• Clinical Organ transplantation
• Renal Transplantation, RT
• Transplantation Immunology
• MHC and Tissue Matching
• Graft Rejection
• Immunosuppression

• 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.

• First attempts were unsuccesful (MISMATCH)
• Discovery of blood groups (Red cell antigens)
• A-B Landsteiner 1900
• Rh Levine, Stetson 1939
• Succesful transfusion = Transplantation
• Others: Bone, Tissue-engineering, etc
• Transplantation
• Organ Transplantation

• Auto-RT

Cadaveric

• Allograft RTLiving related

Living Donor

Living unrelated

• Xenograft RT (In experimental)

• 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

• 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

• 1933 First clinical RT (Voronov);
• 1954 First long-term successful RT(Twin);
• 1958 Discovery of HLA(Human Lym Antigen);
• 1959 Radiation be used for immunosupp-

ression;

• 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).

• Knowledge of MHC haplotypes
• Effective immunosuppression
• Ability to identify and treat infections
• Available donors

Applications of allografting transplantation

Clinical Organ Transplantation

Liver Transplantation

Renal Transplantation

• Indication: End stage liver diseases (ESLD)
• Hepatic Disease to ESLD
• 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

Definition:

(1) Various causes;

(2) Irreversible injury;

(3) Functional failure.

Morbidity

• Europe:50/million;
• China:90-100/million

• DIALYSIS

Chronic Ambulatory Peritoneal Dialysis (CAPD);

Hemodialysis (HD).

• KIDNEY TRANSPLANTATION

• 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.
• The preferred therapy for most of the Pts with ESRD;
• More cost- effective; Better survival; Better life quality.

• Active invasive infection;
• Active malignance;
• High probability of operative mortality;
• Unsuitable anatomic situation for technical success;
• Severe psychological or financial problem.

• ABO Blood Group:Compatible;
• Cytotoxicity Test:

Donor Lymphocyte Recipient Serum

• Cross matching

Donor Lymphocyte Recipient Serum

Donor Serum Recipient’s Lymphocyte

• Mixed Lymphocyte Culture
• Tissue typing (HLA)

DONOR

(1)Living donor

• Nephrectomy via flank approach;
• Nephrectomy via Laparoscope.

• Total midline incision;
• in situ flashing: Euro-collins/UW solution;
• Bilateral radical nephrectomy.
• Low temperature preservation.

• Better short-term result(about 95% versus 90 % 1-yr function);
• Better long-term results(half-life of 12-20 yr versus 8-9 yr);
• More consistent early function and easy of management;

• Avoidance of brain death stress;
• Minimal incidence of delayed graft function;
• Avoidance of long wait for cadaveric transplant;

• 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.

• Psychological stress to donor and family;
• Inconvenience and risk of evaluation process(i.e., intravenous contrast);
• Operative mortality(about 1 in 2000 Pts.);
• Major post operative complications (about 2% of Pts.);

• Minor postoperative complications(up to 50% of Pts.);
• Long-term morbidity(possible mild hyper-tention 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 ?

• Blood Vessel Anastomosis:
• Donor renal V Recipient’sexternal iliac V
• Donor renal A Recipient’s internal iliac A
• Ureter Anastomosis:
• Donor ureter Recipient’s bladder
• Anti-reflux anastomosis

• Hyperacute rejection(minutes to hours)
• Preexisting antibodies to donor HLA antigens
• Complement activation, macrophages
• Accelerated rejection
• Acute rejection(around 10 days to 30 days)
• Cellular mechanism (CD4, CD8, NK, Macrophages)
• Chronic rejection(months to years !!)
• Mixed humoral and cellular mechanism
• CHRONIC REJECTION IS STILL HARD TO MANAGE !

• Immunosuppresents play a very impor-tant role in organ transplantation;
• Immuosuppresents extremely increase the effect and the survival rate of organ transplantation;

• Immunosuppresents are a double - edged sword;
• 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.).

Symptom/Sign

• fever;
• urinary output ;
• graft tenderness;
• graft size ;
• hypertension;
• myalgia/arthragia.

• Serum creatine, SCr;
• Urinary creatine, Ucr;
• Color doppler scan;
• radiorenogram;
• Ateriogram;
• Biopsy:

(1) Fine needle aspiration biopsy

(FNAB);

(2) Core needle biopsy(CNB).

• Hyperacute (Sometimes during the operation !)
• No therapy, usually results in graft failure – kidney should be removed
• Acute (Most frequently in the first 4 weeks)
• BIOPSY !
• Increase immunosuppression
• Increase steroid dose
• Increase cyclosporin (monitor serum level !)
• ATG, ALG, OKT3
• Chronic
• ACE inhibitors, prostacyclin analog drugs
• Steroid, Imuran, Cellcept

Transplantation Immunology

• Major histocompatibility antigens
• MHC class I molecules : almost all nucleated cells
• MHC class II molecules : APCs, endothelium of renal arteries and glomeruli
• Minor histocompatibility antigens : H-Y molecule

• Human leukocytic Antigen
• HLA I. (α1, α2, α3, β2-microglobulin)
• Gene-Code alleles: A, B, C loci
• HLA II. (α1, α2, β1, β2)
• Gene-Code alleles: DP, DQ, DR loci
• HLA III.
• Gene-Code alleles: C4A, TNF, HSP70
• MHC complex: Gene

• 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

Mother

Father

A/B

C/D

A/C A/D B/C 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

• 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

• Senzitization stage

Not needed in hyperacute reactions !

• Effector stage
• Alloantibodies: bind to endothelium, activate the complement system, and injure graft blood vessels

• Effector stage (Mostly cellular mechanism)
• Alloreactive T cells : recruit and activate macrophages ---> DTH response delayed type hypersensitivity
• Alloreactive CTLs: CTL mediated cytotoxicity lyse graft endothelial and parenchymal cells directly
• ADCC

CD4, CD8 lymphocytes, NK cells, macrophages

From: Kuby: IMMUNOLOGY (fourth edition, 2000)

• 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)

• 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

• Occurs within days or weeks after transplantation
• Acute vascular rejection
• Necrosis of cells of the graft blood vessels (vasculitis)
• Mediated by IgG antibodies against endothelial cell alloantigens and complement activation

• Acute cellular rejection
• Necrosis of parenchymal cells with lymphocyte and macrophage infiltrates
• Effector mechanisms :
• CTLs
• Activated macrophages
• Natural killer cells

• 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

• Immunosuppression
• drugs that inhibit or kill T lymphocytes
• toxins that kill proliferating T cells
• antibodies that deplete or inhibit T cells
• anti-inflammatory agents

• Reduce the immunogenicity of allografts
• ABO blood group typing
• HLA typing and matching
• induce donor-specific tolerance
• blood transfusion

• 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

• Epithelial cell necrosis :
• Skin
• Liver
• The gastrointestinal tract
• Characterized by skin rash, jaundice and diarrhea

• Allogenic transplantation always require immunosuppressive therapy
• Most of the drugs available are non-specific
• Common side effects of therapy:
• Infection
• Cancer
• Bone-marrow depression

• Conventional drugs(1st phase)
• 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)

• New drugs (1):
• CYCLOSPORIN A (=REVOLUTION !)

2-8 mg/ kg

• FK506 tacrolimus /PROGRAF/
• Sirolimus - rapamycin
• Gusperimus - dezoxyspergualin

• 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.

• Purin antagonists
• IMURAN
• CELLCEPT (micophenolate mofetil)
• Mizoribin – bredinin
• Pirimidin antagonists
• Sodium-brequinar (highly lymphocyte specific)

• OKT3 (Anti CD3 mAb)
• CD3 T cells
• Anti-TAC (anti-IL2 receptor)
• Activated T lymphocytes
• Anti-CD4
• Anti-LFA1 + anti-ICAM-1 – experimental
• Anti-cytokine (IL-2, TNFα, IFNγ)

• There are not enough organs
• 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:
• When the immune system of the host detects foreign graft tissue, it launches an attack, resulting in tissue rejection

• Gene technology offers the possibility to breed the desired organs in animals.

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

3. The Pig:

Surprisingly similar to our anatomy and physiology

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

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.

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.

• 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.

• 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.

• 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