W03_09 transplant immunology Flashcards
where is HLA class I expressed?
most cells in the body
where is HLA class II expressed?
APCs - dendritic cells, macrophages, B cells
which chromosome is HLA located?
chromosome 6
note: the HLA A2 allele is present in about 50% of the population
okay.
what are the 8 important loci for transplantation?
A,B,C,DR,DQ,Dqalpha,DP,Dpalpha
what’s the effect of HLA matching on graft survival? (kidneys)
clear benefit of receiving a 0 mismatch organ, but not much between 1vs2, 2 vs 3, etc
what’s more important than the degree of HLA mismatch for transplantation?
presence of anti-HLA antibodies (Donor-Specific Antibodies)
how can we detect for the DSA?
look at serum of recipient (crossmatching)
what is the complement-dependent cytotoxicity crossmatch test?
take recipient serum and mix with donor T cells. If cells get attacked by MAC complex, then DSA exists
what happens if we transplant a positive CDC crossmatch organ?
hyperacute rejection (antibody mediated)
what are other crossmatching tests?
flow cytometry with cells, flow cytometry with beads that have the donor HLA antigen
what happens when you transplant after positive DSA but negative CDC crossmatching?
acute antibody-mediated rejection (C4d deposition)
what is the panel reactive antibody?
test recipient’s serum against a variety of class I and II HLA antigens - a “virtual crossmatch”
note that the general PRA was found to be significant in one old study, but nonsignificant in a new study
okay.
how to treat transplant patient who’s positive for DSA matching?
“desensitization” - do something to lower antibodies in blood
