HLA and Parentage Testing Flashcards
HLA genetic region
aka MHC (Major Histocompatibility Complex)
Responsible for recognition and elimination of foreign tissues
HLA complex
Contains approximately 40 genes
Grouped into 3 regions on Chromosome 6
Class I region
Genes for transplantation molecules
HLA-A, HLA-B, HLA-C, HLA-E, HLA-F, HLA-G
Class II region
HLA-DR, HLA-DP, HLA-DQ
Class III region
genes for many molecules:
Complement factors, 21-hydroxylase, and tumor necrosis factor
General Info on HLA genes
Highly polymorphic
Several alleles at single locus
Individuals HLA expression
Individual has 2 examples of chromosome 6
Possess two HLA haplotypes
Autosomal and Codominant
Class I molecular structure
Consist of Heavy chains on the cell surface
Hydrophobic sequence inserted through the cell membrane
Class I molecules found
Surface of platelets
Most nucleated cells of the body
- including lymphocytes, granulocytes, and monocytes
NOT found on erythrocytes
Class II molecular structure
One heavy and one light chain on cell surface
Two hydrophobic sequences through the membrane
Class II molecules found
Present on B lymphocytes
Cells of monocyte/macrophage lineage
T lymphocytes and other cells AFTER stimulation
Expression of HLA antigens involved in
Antigen presentation and cellular immunity
Rejection of transplanted tissue
Immune mediated platelet refractoriness
Febrile non-hemolytic transfusion reactions
TRALI
Post transfusion GVHD
Disease Association
Antibodies
IgG
Some Bga (HLA-B7)
Cause of rearrangement of HLA genes and production of new haplotypes
Crossing over
HLA Detection
Microlymphocytotoxicity - most commonly used procedure for typing of Class I antigens
ELISA testing - used purified HLA antigens
