- What is the biggest drawback to allograft survival
- Graft Rejection
- List the laboratory tests done before transplantation
- HLA typing
- HLA and Non-HLA antibody screening
- T and B cell cross-matching
- List the tests done under Tissue (HLA) typing
- Serology – Complement dependent cytotoxicity (CDC) test
- Molecular – Sequence specific Oligonucleotide (SSO) and Sequence Specific Primer (SSP) Polymerase Chain Reaction
- List the tests done under HLA antibody screening
- Serology
- Complement-dependent cytotoxicity (CDC)
- CDC-anti-human globulin (CDC-AHG)
- Solid phase
- ELISA
- Flow cytometry or Luminex (Single-antigen beads)
- Serology
- List the tests done under T and B cell Cross-match
- CDC assay
- Flow-cytometry cross match
- Luminex bead assay
- Outline the procedure for the Complement Dependent Cytotoxicity (CDC) test
- Donor’s cells (Buffy coat prep) are mixed with serum containig anti-HLA antibodies
- Antibodies recognize and bind to HLA epitopes on donor cells
- Binding activated complement lysing the donor cells
- Donor cells take up tryptan blue dye
- Positive reactions shows cells that have taken up dye on the microtitre plate
- Negative reaction shows no uptake of dye on the microtitre plate
- Outline the procedure for the Sequence Specific Probe and Sequence Specific Oligonucleotide PCR
- Donor’s Template strand is denatured
- Donor’s DNA is hybridized with fluorochrome-tagged locus specific primers
- Donor’s DNA is amplified
- Donor’s DNA is denatured
- Cycle continues
- PCR products are hybridized with HLA allele-specific probes coated with Luminex beads
- Fluorochrome is detected by Luminex
- What reagents are used in Antibody screening
- Recipient serum with anti-HLA antibodies
- Donor lymphocytes (for CDC)
- Complement
- Fluorescent-conjugated anti-human globulin
- ELISA uses purified HLA antigens as the base (indirect-ELISA)
- Luminex used Microbeads with HLA antigens as the base (detected by luminex)
- Outline the procedure of a CDC cross-match
- Recipient serum mixed with Donor lymphocytes
- Recipient antibody recognizes HLA on donor lymphocytes
- Complement activation, lysis, dye uptake
- Outline the procedure of a Flow cytometry cross-match
- Recipient serum mixed with donor lymphocytes and Fluorochrome-labelled anti-human antibodies
- Recipient antibodies bind HLA on donor lymphocytes
- Fluorochrome labelled secondary antibody binds and is detectable by flow
- Outline the complications of transplantation
- Graft related
- Graft rejection
- Graft vs host disease
- Immunosuppression related
- Opportunistic infections
- Reactivation of latent infection (Polyoma virus)
- EBV induced lymphomas
- HPV induced SCC
- Kaposi sarcoma
- Post-transplant malignancy
- Non-Hodgkin lymphoma
- Non-melanoma skin cancer (SCC)
- Kaposi sarcoma
- HCC
- Anal or vulval carcinoma
- Graft related
- What are the complications of Hematopoietic Stem Cell (HSC) transplant
- Graft failure
- Graft vs Host Disease
- Immunosuppression related complications
- Post-transplant infections
- Post-transplant malignancy
- Hepatic veno-occlusive disease (VOD)
- Engraftment syndrome
- List the types of Graft rejection
- Hyperacute rejection
- Acute rejection
- Chronic rejection
- Briefly describe Hyperacute rejection
- Type II hypersensitivity
- Preformed recipient antibodies against class I HLA molecules or ABO antigens of the donor – pregnancy, transfusion, previous rejected transplant
- Activation of complement system and adhesion to cells (deposition)
- Thrombosis of vessels (after endothelial damage)
- Graft ischemia
- What is seen on biopsy during Hyperacute rejection
- Biopsy shows small vessel thrombosis, ischemia and necrosis
- Briefly describe Acute rejection
- Allorecognition – Direct (no processing) or indirect (need to be processed)
- T-lymphocyte induced humoral or cellular immunity
- Type IV hypersensitivity (Acute cellular rejection)
- Donor MHC II antigens react with host CD4+ T cells (il-12, b7 cd28)
- Differentiate into Th1 cells
- Release of IFN-y
- Macrophage recruitement
- Parenchymal and endothelial inflammation
- Donor MHC I reacts with host CD8+ T-cells
- Direct cytotoxic damage
- Donor MHC II antigens react with host CD4+ T cells (il-12, b7 cd28)
- Type II hypersensitivity (Acute humoral rejection)
- Pre-formed antibodies
- B-cell activation and antibody secretion
- Reaction against donor HLA-antigens
- What is seen on biopsy during Acute rejection
- Biopsy shows dense interstitial lymphocyte infiltration with vasculitis
- Positive C4d staining = humoral rejection
- Negative C4d staining = cellular rejection
- Graft eosinophilia in liver transplant
- Biopsy shows dense interstitial lymphocyte infiltration with vasculitis
- Briefly describe Chronic rejection
- Idiopathic Type II hypersensitivty and type IV hypersensitivity
- Results in intimal fibrosis of graft vessels and graft atrophy
- What is seen on biopsy during Chronic rejection
- Biopsy shows
- Arteriosclerosis
- Interstitial fibrosis
- Obstruction of vessels
- Vascular smooth muscle proliferation
- Graft atrophy
- Organ-specific biopsy shows
- Kidney = Glomerular sclerosis
- Heart= Accelerated CAD
- Liver = Vanishing bile ducts
- Lungs = Bronchiolitis obliterans
- Biopsy shows
- Briefly describe Graft Vs Host disease (GvHD)
- Damage to host as a result of systemic inflammation induced by T-lymphocytes in the graft typically after lymphocyte rich organ transplants in an immunodeficient recipient OR HLA mismatch (HLA-A, HLA-B, HLA-DR)
- Transfusion of non-irradiated blood products
- Liver transplant
- Allogenic HSC transplant – Graft vs Tumor effect
- Small bowel transplant
- Damage to host as a result of systemic inflammation induced by T-lymphocytes in the graft typically after lymphocyte rich organ transplants in an immunodeficient recipient OR HLA mismatch (HLA-A, HLA-B, HLA-DR)
- How does Graft vs Host disease present
- GIT manifestation: Diarrhea
- Skin manifestation: Rash
- Liver manifestation: Jaundice
In a tabular format, distinguish between Hyperacute vs Acute vs Chronic Graft rejection
| Hyperacute | Acute | Chronic | |
|---|---|---|---|
| Onset | < 48 hours (immediate | > 6 months | > 6 months |
| Risk factors | ABO incompatibility, HLA incompatibility | HLA incompatibility, Inadequate immunosuppression | Previous acute rejection, Poor HLA match, Prolonged cold ischemia time, Hyperlipidaemia, Inadequate immunosuppression |
| Features | Thrombosis of vessels and graft ischemia | Pain in graft region, graft edema, fever | Slow, progressive loss of organ function |
| Treatment | Remove graft | Change or increase dose of immunosuppressant | Remove graft |
| Prevention | Pre-op cross-match and ABO grouping | Pre-op cross-match and ABO grouping, HLA matching, Immunosuppression | Irreversible with no known prevention |
In a tabular format, distinguish between Acute vs Chronic Graft versus host disease
| Acute GvHD | Chronic GvHD | |
|---|---|---|
| Onset | <100 days post-transplant | >100 days post-transplant |
| Pathophysiology | Type IV hypersensitivity triggered by donor lymphocytes | Both cell mediated and humoral processes |
- List the sources of stem cell transplant
- Bone marrow transplant
- Peripheral blood stem cell transplant
- Umbilical cord transplant
