2. Rejection is a complex process in which
“recepient immune system recognize
the graft as foreign and attacks it”.
It involves
1. Cell mediated immunity
2. Circulating antibodies
3. It is caused by T-cell mediated reactions.
Destruction of grafts occurs by
1. CD8+ CTLs
2. CD4+ helper cells
Delayed hypersensitivity is triggered by
CD4+ helper cells.
2 pathways
1. Direct pathway
2. Indirect pathway
4.
5. It is called humoral rejections.
2 types
1. Hyperacute
2. Acute
HYPERACUTE:
Presence of preformed antidonor
antibodies.
Transplant rejection has already occurred.
6. ACUTE:
Initial exposure to class I&II HLA
antigens.
Antibodies causes injury by
1. Complement dependent
cytotoxicity
2. Inflammation
3. Antibody dependent cell
mediated cytotoxicity.
8. Occurs within minutes or hours after
transplantation.
Kidney becomes
1. Cyanotic
2. Mottled
3. Flaccid
Immunoglobulin and complement
deposition occurs.
Neutrophils accumulate leading to
occlusion of capillaries & fibrinoid necrosis.
9.
10. Cellular – mononuclear cell infiltrate
Humoral – vasculitis
ACUTE CELLULAR:
Seen within initial months after
transplantation.
Mononuclear cells accumulates in
glomerular and peritubular capillaries
leading to FOCAL TUBULAR NECROSIS.
Treatment – cyclosporin.
11.
12. Also known as rejection vasculitis.
Necrotizing vasculitis characterised by
intimal thickening.
Presence of complement breakdown
product C4d – indicator of humoral
rejection.
Treatment – B cell depleting agents.
17. ANOTHER METHOD:
Prevention of host T cells from
receiving co-stimulatory signals (B7-
1&2) from dendritic cells.
DISADVANTAGES:
EBV induced lymphoma
HPV induced squamous cell carcinoma
Kaposi sarcoma
18. Hematopoietic stem cell transplants are
used for
1. Hematological malignancy
2. Aplastic anemia
3. Thalassemia
4. Non hematological cancers
PROBLEMS:
1. Immunodeficiency
2. GVH disease
19. Occurs in any situation in which
“immunologically competent cells or their
precursors are transplanted to
immunologically crippled recipients and the
transferred cells recognize allo-antigens in
the host”.
It may be
1. Acute
2. Chronic
20. Days to weeks after allogenic bonemarrow
transplantation.
Clinical features
1. Generalised rash
2. Jaundice
3. Ulceration of gut
4. Bloody diarrhea
21. Follow acute syndrome or occur insidiously.
Clinical features
1. Cutaneous injury
2. Cholestatic jaundice
3. Esophageal strictures
4. Depletion of lymphocytes
It is a life threatning condition.
Treatment – bonemarrow transplants.