Lecture 24 - HLA Antibodies Flashcards
1
Q
How do HLA antibodies occur
A
- exposure to non self HLA antigens
- blood transfusion
- pregnancy
- previous transplant/tissue
2
Q
What are epitopes
A
- a unique shape or marker carried on an antigens surface that triggers a corresponding antibody response
- the parts of an antigen molecule which contact the antigen binding site of an antibody or T-cell receptor
3
Q
What are allo-epitopes
A
- epitopes that differ among individual members of the same species
4
Q
What are cross reactive epitopes
A
- HLA antibodies that react with more than one gene product/allele
5
Q
What causes HLA cross reactivity
A
- shared epitopes
6
Q
What is a common HLA epitope
A
Bw4/Bw6
7
Q
What occurs for an HLA crossmatch
A
- XM involves incubation of donor cells with recipient serum
- test determines if there is pre-formed antibody in recipient to donor
- multiple sera samples may be used
8
Q
How does antibody testing fit into transplant process
A
- patients are listed for transplant
- prior to this they are HLA typed and have a HLA antibody screen
- patients send monthly bloodwork to the HLA lab for ongoing screening and to have samples available for XM at all times
9
Q
What is the HLA work up of a deceased donor
A
- donor is HLA typed
- HLA typing is entered into national registry
- report is generated with matches
- nephrologist on call decides which recipient(s) to pick
- if patients are high immunological risk the HLA lab repeats the crossmatch with fresh serum
- HLA lab freezes donor lymphocytes for future XM in case of rejection
10
Q
What is the outcome of a transplant
A
- outcomes are monitored by transplant programs
- post-transplant HLA antibody testing is routinely done to check for mismatch
- HLA antibody testing is also done if the patients allograft function is poor or deteriorates
- recipient may be re-listed for transplant if the donated organ ceases to function
