HLA and Parentage Testing

Question 1

HLA genetic region

Answer 1

aka MHC (Major Histocompatibility Complex)
Responsible for recognition and elimination of foreign tissues

Question 2

HLA complex

Answer 2

Contains approximately 40 genes
Grouped into 3 regions on Chromosome 6

Question 3

Class I region

Answer 3

Genes for transplantation molecules
HLA-A, HLA-B, HLA-C, HLA-E, HLA-F, HLA-G

Question 4

Class II region

Answer 4

HLA-DR, HLA-DP, HLA-DQ

Question 5

Class III region

Answer 5

genes for many molecules:
Complement factors, 21-hydroxylase, and tumor necrosis factor

Question 6

General Info on HLA genes

Answer 6

Highly polymorphic
Several alleles at single locus

Question 7

Individuals HLA expression

Answer 7

Individual has 2 examples of chromosome 6
Possess two HLA haplotypes
Autosomal and Codominant

Question 8

Class I molecular structure

Answer 8

Consist of Heavy chains on the cell surface
Hydrophobic sequence inserted through the cell membrane

Question 9

Class I molecules found

Answer 9

Surface of platelets
Most nucleated cells of the body
- including lymphocytes, granulocytes, and monocytes
NOT found on erythrocytes

Question 10

Class II molecular structure

Answer 10

One heavy and one light chain on cell surface
Two hydrophobic sequences through the membrane

Question 11

Class II molecules found

Answer 11

Present on B lymphocytes
Cells of monocyte/macrophage lineage
T lymphocytes and other cells AFTER stimulation

Question 12

Expression of HLA antigens involved in

Answer 12

Antigen presentation and cellular immunity
Rejection of transplanted tissue
Immune mediated platelet refractoriness
Febrile non-hemolytic transfusion reactions
TRALI
Post transfusion GVHD
Disease Association

Question 13

Antibodies

Answer 13

IgG
Some Bga (HLA-B7)

Question 14

Cause of rearrangement of HLA genes and production of new haplotypes

Answer 14

Crossing over

Question 15

HLA Detection

Answer 15

Microlymphocytotoxicity - most commonly used procedure for typing of Class I antigens
ELISA testing - used purified HLA antigens

Question 16

Flow Cytometry of HLA antigen different from microlymphocytotoxicity

Answer 16

Compliment activation not necessary
Antibody specificity can be determined directly
Distinguish between HLA-specific and non-HLA antigens

Question 17

Techniques for HLA crossmatching

Answer 17

Lymphocytoxicity
ELISA
Flow Cytometry

Question 18

HLA Class II Typing

Answer 18

DNA Hybridization

Question 19

HLA antigen that causes ankylosing spondylitis

Answer 19

B27