PRINCIPLES INVOLVED IN ORGAN
TRANSPLANT
By - Dr NAVIL SHARMAGuide – Dr BALCHANDRA KASHYAPI
CONTENTS INTRODUCTION
Definition of terms Transplant immunology Graft rejection
PRINCIPLES Pre-operatives Intra-operatives Post-operative
COMPLICATIONS
RENAL TRANSPLATATION
ETHICAL CONSIDERATIONS
CONCLUSION
INTRODUCTIONDEFINITION OF TERMS
An organ transplant is a surgical procedure in which a failing organ is replaced by a functioning one from a donor with a compatible tissue type.Autograft - Transfer of organ from one part
to another in the same individual. E.g skin
graft, vuscular graft.
Allograft - from one individual to another
of the same species
Isograft - transfer of organ from one
individual to his or her monozygotic twins
Xenograft - transfer of organ from one
individual to another of different species
INTRODUCTIONDEFINITION OF TERMS
Orthotopic graft- graft placed in it normal anatomical position
Heterotopic graft - graft placed at a site different from the organ is normally
located
Organs that can be transplanted are:
Heart
Kidneys Liver Thymus
Pancreas Lungs Intestine
Tissues that can be transplanted are:
Bones Tendons Cornea
Vein Heart valves Skin of leg
TRANSPLANT IMMUNOLOGYThe immune system recognizes graft from someone else as foreign body and triggers
response via immune cells and substances they produce - cytokines and antibodies
(Responses are via; recognition, amplification and memory)
Immunity
IMMUNE CELLS
Lymphocytes : T-lymphocyte, B-lymphocyte, N-killer cells
Antigen presenting cells(APC) : macrophages, dendritic cells
The Effector Cells : Neutrophils , macrophages and T-lymphocytes
Humoral (Antibody mediated)
Cell mediated
LYMPHOCYTES T-LYMPHOCYTES
o Mediator of cell mediated immunity
o They recognizes MHC antigen on transplant tissues
o Cytotoxic T-cells produces cytotoxic factors (perforins, granzymes) implicated
in transplant rejection
B-LYMPHOCYTES
o Mediators of humoral immunity by antibody production.
o There activation is aided by cytokine and the T-helper cells
o Clonal selection generates plasma cells secreting antibodies.
o There are 5 major classes of antibodies or immunoglobulin; IgG, IgM, IgA, IgE and
IgD the 1st 3 are involve in graft rejection
N-KILLER CELLS
o Cells of innate immunity, capable of killing foreign targets without prior
sensitization
Cell-mediated immune response
Defend against intracellular pathogens/rejection
ActiveCytotoxic T cells
MemoryCytotoxic T cells
MemoryHelper T cells
Antigen-presenting cell
Antigen (2nd exposure)
Helper T cell
Engulfed by
Antigen (1st exposure)
Cytotoxic T cell
KeyStimulatesGives rise to
+
+
+
+
+ +
+
T-CELLS- Helper T cells- Cytotoxic T cells- Memory T cells
Cytotoxic T cell
PerforinGranzymes
TCRCD8
Class I MHCmolecule
Targetcell
Peptideantigen
Pore
Released cytotoxic T cell
Dying target cell
KeyStimulatesGives rise to
+
MemoryHelper T cells
Antigen-presenting cell
Helper T cell
Engulfed by
Antigen (1st exposure)
+
+
+
+ +
+
Defend against extracellular pathogens/Transplant rejection
MemoryB cells
Antigen (2nd exposure)Plasma cells
B cell
Secretedantibodies
Humoral (antibody-mediated) immune response
11
ANTIGEN PRESENTING CELLS(APC)o They capture antigens and display to lymphocytes e.g. Macrophages, dendritic cells
and follicular dendritic cells.
• Dendritic cells : initiate T-cells response
• Macrophages : Initiate effector phase of cell mediated immunity
• Follicular dendritic cells : display antigens to B-lymphocytes in humeral
response.
EFFECTOR CELLSo They eliminate antigens by phagocytosis
E.g neutrophils, macrophage and T-lymphocytes
TRANSPLANT ANTIGENS
Human leucocytes antigen (HLA) ;a group of highly polymorphic cell surface molecules
They act as antigen recognition unit on T-lymphocytes and are the major trigger for
graft rejection
Types : class1 – HLA- A,B,C present in all nucleated cells,
CD8+ recognizes class 1 HLA
class2 – HLA- DR, DP, DQ present only on APC
Class 2- HLA-DR are most important in rejection
CD4+ recognize class 2 HLA
Major histocompatibility complex MHC;o They are clusters of genes on the short arm of
chromosome 6 expressed on the cell surface as HLA i.e. genes that encode HLA.
ABOo These blood group antigen are expressed not only on
red blood cells but by most cell types as well.o Incompatibility leads to hyperacute rejection
Rejection of transplanted organs is a bigger challenge than the
technical expertise required to perform the surgery. It results mainly from HLA and ABO
incompatibility.Types of Graft Rejection
Hyperacute : o Immediate graft destruction due to ABO or preformed
anti- HLA antibodies.o Characterized by intravenous thrombosis and
interstitial hemorrhage.o Risk factors are previous failed transplant and blood
transfusionso Kidney transplant is vulnerable to hyperacute
rejection . Hyperacutly rejecting kidney rapidly becomes cyanotic, mottled, and flaccid and may excrete few drops of bloody urine.
o This form of rejection is rarely seen in today's practice
GRAFT REJECTION
Steps in the hyperacute rejection of a kidney graft.
Hyperacute Rejection
Acute :o Usually occurs during the first 6 months. o May be cell mediated (T-cell), antibody mediated or both.
o Characterized by cellular infiltration of the graft (cytotoxic, B- cells, NK cells
and macrophages).
o Histologically, humoral rejection is associated with vasculitis, whereas cellular
rejection is marked by an interstitial mononuclear cell infiltrate, edema, and
tissue injury as well as mild interstitial haemorrhage.
Chronic :o It occurs after 6 month .o Most common cause of graft failure. o Non- immunological factors contribute to the pathogenesis characterized by
myo-intimal proliferation in graft arteries leading to ischemia and fibrosis
PRINCIPLES
PRE-OPERATIVE
Patient selection and Evaluation
Counseling
Informed consent
Optimization
PATIENT SELECTION AND EVALUATION
1. RECIPIENT Patient who met the indication for transplant – ORGAN FAILURE
Clinical evaluation; history and physical examination to rule out other
diseases and co-morbidities
Immunological evaluation Blood group
Tissue typing & cross matching
Serology; HIV, Hepatitis, CMV, VDRL
Infection screening – septic work-up
Others ; CBC, clotting profile, FBS, ECG, LFT, RFT, tumour markers.
2. DONOR
I. Living donor : Donor remains alive and donates a renewable tissue/cell,
or donates an organ or part of an organ in which the remaining organ can
regenerate or take on the workload of the rest of the organ (single kidney donation,
partial donation of liver). A living donor should be healthy• Living unrelated donor (LURD)
• Living related donor. (LRD)
Advantages of living donor Improved graft survival
Less recipient morbidity
Early function and easier to manage
Avoidance long waiting time for transplant
Less aggressive immunosuppressive regimen
Contra-indications for living donoro Mental disease
o Disease organ
o Morbidity and mortality risk
o ABO incompatibility
o Crossmatching incompatibility
o Transmissible disease
Evaluation : to assess for suitability
o CLINCAL - history of risk factors for infection, malignancy in the past 5
years. Presence of co-morbidities
o ABO typing, Serology tests.
o Infection and malignant screening
o CT-Angiogram, Intravenous urography.
o HLA typing.
II. Deceased donor- Brain dead donors: Donors who have been declared brain-dead and whose
organs are kept viable by ventilators or other mechanical mechanisms until they can
be excised for transplantation.
o Normothermic patient.o No respiratory effort by the patient.o The heart is still beating.o No depressant drugs intake should be there while evaluating the
patient.o Individual should not have any sepsis, cancer (except brain tumour).o Not a HIV or hepatitis individual.
- Cardiac Death Donors (formerly non-heart beating donors) to increase the
potential pool of donors as demand for transplants continues to grow. These organs
have inferior outcomes to organs from a brain-dead donor.
FACTORS DETERMING ORGAN FUNCTION AFTER TRANSPLANT
DONOR CHARACTERISTICS■ Extremes of age
■ Presence of pre-existing disease in the transplanted organ
■ Haemodynamic and metabolic instability
PROCUREMENT-RELATED FACTORS■ Warm ischaemic time
■ Type of preservation solution
■ Cold ischaemic time
RECIPIENT-RELATED FACTORS■ Technical factors relating to implantation
■ Haemodynamic and metabolic stability
■ Immunological factors
■ Presence of drugs that impair transplant function
Tissue typing
The tissue typing laboratory carries out 3 tasks :
To determine the HLA type of blood for both donor and recipient by
PCR.
Lymphocyte cross-matching to exclude circulating antibodies in
recipient against HLA expressed by donor.
HLA antibody screening and specificity in recipient before and after
transplant to guide immunosuppressive therapy
Positive cross matching; o Recipient antibodies attacks donor’s.
o Not suitable for transplant
Negative cross matching; o Recipient antibodies donot attack donor
o Suitable for transplant
Methods;
o Micro-cytotoxic assay, mixed lymphocytes, flow cytometry,
DNA analysis.
Lymphocyte cross-matching
Typing procedures for HLA antigens. (a) HLA typing by microcytotoxicity.
(b) Because cells express numerous HLA antigens, they are tested separately with a battery of antibodies specific for various HLA-A antigens. Here, donor 1 shares HLA-A antigens recognized by antisera in wells 1 and 7 with the recipient, whereas donor 2 has none of HLA-A antigens in common with the recipient
Graft Donors and Recipients Are Typed for RBC and MHC Antigens
O May involve professional counselors/ psychotherapist
O Aimed at preventing / minimizing possible complication
O Need for adherence to post-op maintenance medications
O Regular follow-up thorough evaluation
O Life style modification; smoking, alcohol, sedentary life style, junks,
excessive salt ingestion.
COUNSELING
INFORMED CONSENT
Living Donor ; Education
Willingly not for any financial reason or under stress
Most undergo extensive screening – medical, psychological
Surgery and anesthetic complications outline to patients
DECEASED DONOR Some Factors influencing refusal to consent by relatives;
non-acceptance of brain death.
A delay in funeral
Lack of consensus within family members
Fear of social criticism
Dissatisfaction with the hospital staff
Various Superstitions & Religious beliefs
INFORMED CONSENT
RECIPIENT
Nature of disease and the need for transplant
Outcome and complications
Need for compliance to immunosuppressive therapy
Other available options
OPTIMIZATION OF RECIPIENT
Correction of derangements, getting patient ready for surgery
Correction of anemia
Uremia
Dehydration
Treatment of infection
Central line
Urethral catheter
Loading dose immunosuppression 12hr pre-op
Prophylactic antibiotics
PRINCIPLES
INTRA-OPERATIVE
Organ procurement and preservation
LIVING DONORsa. Strict asepsis and hemostasis
b. Adequate exposure
c. Removal of the organ
d. Preservation
Preservation
After removal, the
organ is flushed with chilled
organ preservation solution
e.g.
University of Wisconsin(UW),
Eurocolins,
HTK,
Celsior,
Custodiol,
Citrate/Marshall solutions
g. Organ packaging
NONHEART-BEATING KIDNEY DONATION
Initiation of preservation in situ- for DCD donors- donation after circulatory death donors
h. Transplantation/vascular reconstruction
Warm ischemic time ; time an organ remains at body temperature
between which the blood supply is cut off before cold perfusion. (within
30min)
Cold ischemic time ; the time between the chilling of the organ, after
blood supply has been cut off and the time it is warmed by reconnection
Maximum and optimal cold storage times (approximate)Organ Optimal (hours ) Safe maximum(hours) Kidney < 24 48Liver < 12 24Pancreas < 10 24Small intestine < 4 8Heart < 3 6Lung < 3 8
PRINCIPLES
Post-operativePost-operative assessment
Clinical – vital signs; fever, tachychardia, hypertension, pain at site of
transplant, pedal edema (compression of external iliac vein), decrease urine
volume- features of hyperacute rejection
Investigations ; U/Scr USG- increase in size, pelvicalyceal dilation
Biopsy; mononuclear infiltrates, fibrinoid necrosis, interstitial
haemorrhage. Others
Maintenance immunosuppression, DVT prophylaxis
Treatment of infection , Regular follow up
IMMUNOSUPPRESSION
The principles are the same for all type of organ transplant; maximize graft
protection and minimize side effect.
The agents used to prevent rejection act predominantly on T cells.
The need for immunosuppression is highest in the first 3 month but indefinite
treatment is needed
It increase the risk of infection and malignancy.
AGENT MODE OF ACTION SIDE FFECT
CALCINEURINE INHIBITORSCyclosporineTacrolimus
Block IL-2 gene transcription
Nephrotoxicity, hypertension,dyslipidaemia, hirsutism, gingival hyperplasia, neurotoxicity and diabetes
AZATHIOPRINE Prevents lymphocyteproliferation
Leucopenia, thrombocytopenia,hepatotoxicity, gastrointestinalsymptoms
MYCOPHENOLIC ACID DERIVATIVES eg MMF –Mycofenolate mofetil
Prevents lymphocyteproliferation
Leucopenia, thrombocytopenia,gastrointestinal symptoms
CORTICOSTEROIDS Widespread anti-inflammatoryeffects
Hypertension, dyslipidaemia, diabetes,osteoporosis, avascular necrosis,cushingoid appearance
mTOR-inhibitors Sirolimus, Everolimus
Blocks IL-2 receptor signaltransduction
Thrombocytopenia, dyslipidaemia,pneumonitis, impaired woundhealing
AGENT MODE OF ACTION SIDE EFFECT
ANTIBODY THERAPIES a. OKT3 monoclonal
antibodyb. Anti-CD25
monoclonal antibody
c. Polyclonal antibody [antilymphocyte globulin (ALG) or anti-lymphocyte serum (ALS)]
Depletion and blockade of TCellsTargets activated T cells
Depletion and blockade oflymphocytes
a. Cytokine release syndrome, pulmonary oedema, leucopenia
b. None describedc. Leucopenia,
thrombocytopenia
REGIMENS
Immunosuppressive agents are given as
Induction; early post-op period
Maintenance ; given for life
Rescue agents ; to reverse acute rejection
Induction regimen (most currently used )
CNI + anti CD 25 monoclonal antibody
Triple therapy ; CNI, anti-proliferative agent (MMF) and steroids
Dual therapy ; CNI + MMF or steroids
Polyclonal antibody (ALG/ALS)
Maintenance ; mTOR- inhibitors (specially in kidney transplant because they provide a
non-nephrotoxic alternative to CNI)
Multidrug therapy ; steroids, anti-proliferatives, CNIs.
Acute Rejection; Polyclonal antibody combine with induction regimen- quadruple therapy.
COMPLICATIONS OF IMMUNOSUPPRESSION
INFECTIONS; high risk of opportunistic infections
o Bacterial : common during first month after transplantation
Community acquired infections
Wound infection
UTI (catheter related)
Tuberculosis
COMPLICATIONS OF IMMUNOSUPPRESSION
o Viral ; highest in the first six month
• CMV infection; may presents as pneumonia, gastrointestinal disease,
hepatitis, retinitis, encephalitis
• Herpes simplex virus (HSV) ; muco-cuteneous lesions sometimes
around the genitalia
• BK-virus; graft dysfunction
• Herpes zoster infection; chicken pox
o Fungal ; pneumocystis jiroveci (carinii), candidiasis, aspergillosis
o Parasitic; strongiloides, leishmaniasis, toxoplasmosis
COMPLICATIONS OF IMMUNOSUPPRESSION
MALIGNANCYo Post transplant lymphoprolipherative disease (PTLPD); seen 1-3% of
kidney transplant with 50% mortality
o Squamous cell ca of the skin
o Basal cell ca and malignant melanoma are higher in transplant patient than the
general population
o 50% of transplant patient would develop skin malignancy in 20years
o Kaposi sarcoma; 300 fold increased risk
KIDNEY TRANSPLANT
Indications o End-stage renal disease
Causes : Glomerulonephritis;
Diabetic Nephropathy;
Hypertensive Nephrosclerosis;
Renal Vascular Disease;
Polycystic Disease;
Pyelonephritis;
Obstructive Uropathy;
Systemic Lupus Erythematosus;
Analgesic Nephropathy;
Metabolic disease (oxalosis, amyloid).
Irreversible GFR of less than 10 mL/min
serum creatinine level of greater than 8 mg/dl
O
Exclusion criteria for living donor
Exclusion Criteria for Recipient Drug abuse.
Morbid obesity. BMI >/= 35 Compliance
• S. phosphorus </= 6mg/dl
• Inter-dialysis wt gain (<5% dry wt for period of 3 month)
High risk of heart disease.
Cause of ESRD
• Focal segmental glomerulosclerosis
• Hemolytic uremic syndrome.
• 10 Oxalosis
Active Infection
Active malignancy
O DONOR NEPHRECTOMY
O DONOR BENCH SURGERY
O TRANSPLANTATION
OPERATIVES
Donor Nephrectomy
Open or Laparoscopic or Robotic.
Laparoscopic donor nephrectomy is the gold standard.
Open donor nephrectomy is via the 11th/12th rib cutting incision, and in fat
patient 10th rib cutting incision.
Extraperitoneal : avoid de-vascularizing ureter, sharp dissection, avoid
diathermy near vessels
Renal vasculature dissect flush to IVC/Aorta
Ligate lumbar veins posteriorly ± gonadal vein
Donor Kidney Bench Surgery
o The kidney is perfused with ice-cold preservative
o Iced saline is mashed into a slush and kidney immersed
o Extra veins ligated, accessory artery(ies) anastomosed together
o Kidney now ready for transplanting
PRESERVATIVESIschemia
Na pump is impaired
NaCl and water passively diffuse into the cell
Cellular swelling & NO-REFLOW phenomenon
Cellular K & Mg lost.
Ca + gained
Anaerobic glycolysis and Acidosis
Lysosomal enzymes activated
On reperfusion, Hypoxanthine a product of ATP
degradation is oxidized to xanthine and free
radicals causes further injury
ATP and Oxygen depletion
Patho-physiology
ATP-MgCl2
Ca+ channel blocker
Vaso-protective agents
Free radical scavenger
Lysosome stabilizer
(Methylprednisolone)
THE TRANSPLANT
o Right donor kidney to left recipient site and vice versa
o Gibson’s incision; Curvilinear incision 2 cm above the inguinal
ligament, from midline to just above the anterior Sup. Iliac Spine
o End to side venous anastomosis 5/0 prolene
o End to end arterial anastomosis 5/0 prolene
o Implant ureter to bladder
Recipient Preparation
o Antibiotic administered just before surgery.
o Immunosuppression started just before or during surgery.
o Before temporary vascular occlusion HEPARIN is given I/V to recipient.
Indication for pre-transplant Nephrectomy
o Renal stone not cleared.
o Polycystic symptomatic (infected) kidney.
o Persistent anti glomerular basement membrane antibody.
o Significant protienuria.
o Recurrent pyelonephritis.
o Grade 4/5 Hydronephrosis
Extra-peritoneal approach in either iliac fossa. Renal artery is anastomosed end-to-end to the internal iliac artery or end-to-side to the external iliac artery. Renal vein is sutured end to side to external iliac vein. After revascularization, the ureter is implanted into the side wall of the bladder
COMPLICATIONS
TECHNICAL Vascular hemorrhage; Vascular thrombosis 10-20%, within 2-3
days→ technical, 2/12→rejection, most are lost: ↓urine output, ↑creatine
Urological ; infection, fistula, obstruction Wound infection
RENAL Acute tubula necrosis Cortical necrosis Lymphocele Graft rupture Recurrent glomerulo-nephritis
Outcome Patient survival after deceased donor renal transplantation is >90% at 1 year and
> 80% at 5 years.
Graft survival is around90% at 1 year and 75% at 5 years. Graft survival after a
second transplant is only marginally worse than after a first graft.
After living-related kidney transplantation, overall graft survival is around 95% at 1
year and 85% at 5 years.
The half-life of grafts obtained from living donors is longer than that of cadaveric
grafts:
• deceased donor grafts : 13 years;
• living unrelated grafts : 14 years;
• living haplo-identical grafts : 15 years;
• living identical sibling grafts : 27 years
ETHICAL CONSIDERATION
INTERNATIONAL PERSPECTIVES ON THE ETHICS AND
REGULATION OF HUMAN CELL AND TISSUE TRANSPLANTATION o Consent for removal of human cells and tissues
o Confidentiality of donor data
o Unpaid donation
o Fair procurement of cells and tissues
o Stewardship for donated cells and tissues
o Quality and safety of HC/HT procurement and processing
o Fair distribution of processed cells and tissues
o Consent for HC/HT transplantation
Future trend
Genetic engineering – Cloning
Newer specific Immuno-suppresive therapy
CONCLUSION
Organ transplant is a successive therapeutic
option for treatment of end-stage organ disease.
Success depends on improved surgical technique,
immunosuppression, organ preservation and
follow-up .
REFERENCESO Bailey and Love’s “Short Practice of Surgery” 26th
edition CRC press Taylor and Francis group. 2013O E.A Badoe et al, “Principles and Practice of surgery
including pathology in the tropics” 4th edition, Assembly of God Literature Center ltd, 2009
O M.A.R Al-Fallouji; “Postgraduate Surgery the candidate guide”. 2nd Edition. Rced Educational and Professional Pub. Ltd 1998
O Sabiston texbook of surgery. 18th edition.2007O Andrew C et al “Operative urology at the cleveland
clinic” 2nd edition. 2006.O Campbell-walsh urology.