HLA in transplantation and transfusion Flashcards
(29 cards)
What is the function of HLA class I and which cells express these molecules?
Present endogenous antigens to cytotoxic T cells
Expressed on almost all nucleated cells
What is the function of HLA class II and which cells express these molecules?
Present exogenous antigens to helper T cells
Expressed prmarily on anitgen- presenting cells (B cells, macrophages etc)
What is the mode of inheritance of HLA genes?
Inherited via co-dominance
What is the chance of inheriting identical HLA to your sibling?
25%, if the sibling isn’t a twin
Which 3 gene loci are HLA class I and which main 3 are HLA class II?
Class I- HLA-A,B &C
Class II- HLR-DR, DQ &DP
What level of resolution HLA typing is sufficient for solid organ transplant?
High-resolution
What level of HLA typing is required for hematopoietic stem cell transplant (HSCT)?
High resolution for type I and II
What does CDC stand for and how does it work?
Complement-Dependent Cytotoxicity
Works by detecting the presence of antibodies present against HLA antigens
What is added to CDC trays to remove HLA-IgM antibody reactivity and differentiate that from HLA-IgG?
Beta-mercatoethanol is added to reduce IgM antibodies to differentiate them from IgG
What are the advantages of Flow cytometry for crossmatching and HLA antibody detection over CDC?
Higher sensitivity, faster results
What other technique was historically used for HLA antibody detection and how does it work?
Micro cytotoxicity
What is the bead-based flow cytometry technique that is now the gold standard for HLA antibody detection and can also be used for HLA typing?
Luminex xMAP
What techniques can be used for HLA typing and what are the levels of resolution that can be achieved?
Serological- low
PCR-SSP- medium
PCR-SBT- high
Next- gen sequencing- high
How does PCR work?
amplification of specific DNA sequences by using primers that bind to regions of interest
allows for rapid and targeted replication of DNA
Which high resolution HLA typing technique is now routinely used by H&I for HSCT patients and donors?
Next- Generation Sequencing
What tests are required to get a kidney patient listed for transplantation?
Blood tests
HLA typing- to assess immune compatibility
Crossmatching
Viral screening
Imaging- CT scans etc
What tests are required to work-up a potential organ donor?
Blood typing
HLA typing
Crossmatching
Infectious disease screening
Organ function tests
How are kidneys allocated by OTDT – what criteria are considered as part of the algorithm?
Blood type- ABO compatability
HLA matching- degree of tissue compatabiltiy
Age
Geographic location
What effect does matching for HLA have on the outcome/longevity of organ transplants?
Reduce the risk of infection
Inc graft survival
Reducing the need for Immunosuppressive drugs
How are patients monitored post-transplant?
regular blood tests
immunosuppressive drug levels
biopsy- if suspected rejection
clinical assessments
How is the allocation and pre-transplant workup of cardiothoracic organs different to kidneys?
urgency- more critical for heart nd lung transplants
size and match
geographical location
pre-transplant tests
Matching HLA at high resolution is important for HSCT. What condition are we trying to avoid post-transplant?
Graft-versu- host disease (GVHD)
Where do we look for suitable hematopoietic stem cell donors?
national bone marrow registries
international donor registries
family members
cord blood banks- umbilical cord stem cell store
What are the symptoms and causes of FNHTR (Febrile Non-Hemolytic Transfusion Reactions)?
fever, chills discomfort, causes by recipients immune response to donor WBC
