Haem: Bone Marrow Transplantation Flashcards
Which organ in the body is most resistant to radiation?
CNS
NOTE: bone marrow is very vulnerable to radiation
What is the main cellular marker of stem cells?
CD34
What is the risk of dying from bone marrow transplant?
More than 50%
It is the most expensive and risky elective procedure
Outline the process of autologous stem cell transplantation.
- Growht factor is given to the patient to stimulate the production of cells from the bone marrow
- Cells are sampled from the patient’s bone marrow (some of them will be CD34+ stem cells)
- These are preserved in a freezer
- High-dose chemotherapy is given to the patient to eradicate their bone marrow
- Stem cells are re-infused
What are the most common reasons for autologous stem cell transplantation?
- Myeloma
- Lymphoma
- CLL
When is allogeneic bone marrow transplantation used?
- When it is very unlikely that the patient’s disease will be eratdiacted from the bone marrow by standard chemotherapy
NOTE: suitable for acute leukaemia, chronic leukaemia, myeloma, lymphoma, bone marrow failure, congenital immune deficiencies
List some parameters used to gauge outcome of transplantation techniques.
- Overall survival
- Disease-free survival
- Transplant-related mortality
- Relapse incidence
State an equation that relates the probability of having a sibling with a matching tissue type to the number of siblings a patient has.
Probability of match = 1 — (3/4)number of siblings
NOTE: there is a 25% chance that your sibling has the same tissue type as you
What are the main classes of HLA based on?
- Serological reactions (e.g. HLA-A)
- It can be increasingly specified by DNA sequencing
HLA molecules relevent for transplantation
HLA-A, -B, -C : Class I - Present to CD8+ (cytotoxic T cells)
HLA- DP, -DQ, -DR: Class II - Present peptide to CD4+ (Helper T cells)
6 HLAs, 2x Parents = MAtch rated /12
Name three ways of harvesting stem cells.
- Bone marrow sampling
- Peripheral blood sampling
- Umbilical cord stem cells
Why is bone marrow sampling a difficult process?
- It involves anaesthetising the patient and sampling bone marrow from the pelvis
- Puncturing the bone causes damage and only sampling a small number of stem cells means that re-puncturing of the bone is necessary
Outline the process of peripheral blood sampling for stem cells.
- Hormones (e.g. G-CSF) is given to stimulate granulocyte production
- This leads to the bone marrow producing some stem cells along with the granulocytes
- G-CSF is given for 5 days and stem cells are harvested on the 5th day
- The donor is connected to a centrifuge which spins the blood, removes the white cell component, reassembles the red cells and plama and reinfuses it into the patient
What proportion of a sample taken during stem cell sampling actually contains stem cells?
1%
What factor (related to stem cell harvesting) does the success of a bone marrow transplant depend on?
Number of CD34 cells per kg of weight of the recipient