HLA and Tissue Typing

Question 1

What does HLA stand for?

Answer 1

Human Leucocyte Antigens

Question 2

What is the role of HLA?

Answer 2

Determines if something ‘belongs’ to the body or not.

Question 3

How many classical loci of HLA are there?

Answer 3

6. Class I (A,B,C) and Class II (DR, DQ, DP)

Question 4

What are the Class I HLA loci?

Answer 4

A, B ,C

Question 5

What are the Class II HLA loci?

Answer 5

DR, DQ, DP

Question 6

What is the purpose of loci molecules in HLA?

Answer 6

Allow tissue to be recognised as ‘self’ or ‘non self’ by host immune system to determine histocompatibility.

Question 7

What chromosome is HLA found on?

Answer 7

Chromosome 6

Question 8

Where is the HLA region located on chromosome 6?

Answer 8

On the short arm

Question 9

Which HLA class are expressed on almost ALL cells?

Answer 9

HLA Class I

Question 10

Which HLA class recognise intracellular pathogens?

Answer 10

HLA Class I

Question 11

Which HLA class are found on immune cells?

Answer 11

HLA Class II

Question 12

Which HLA Class recognise extracellular pathogens?

Answer 12

HLA Class II

Question 13

How are HLA very Polymorphic?

Answer 13

They have many different alleles. Serve to recognise and initiate an immune response.

Question 14

Which HLA Class are expressed on all nucleated cells?

Answer 14

HLA Class I

Question 15

Which HLA Class are expressed on antigen-presenting cells?

Answer 15

HLA Class II

Question 16

What does HLA-A define on nomenclature?

Answer 16

The locus

Question 17

What does HLA-A24 show on nomenclature?

Answer 17

The antigen has been serologically defined

Question 18

What does the asterisk in ‘HLA-A*24’ show?

Answer 18

This shows that the allele was defined through low resolution molecular methods.

Question 19

What does the ‘:’ in HLA-*24:01 show?

Answer 19

This shows a specific allele from a higher resolution.

Question 20

How many antigens and alleles does HLA A have?

Answer 20

28 antigens. 1729 alleles.

Question 21

How many antigens and alleles does HLA B have?

Answer 21

60 antigens. 2329 alleles.

Question 22

How many antigens and alleles does HLA C have?

Answer 22

10 antigens. 1291 alleles.

Question 23

How many antigens and alleles does HLA DR have?

Answer 23

21 antigens. 1051 alleles.

Question 24

How many antigens and alleles does HLA DQ have?

Answer 24

9 antigens. 160 alleles.

Question 25

How many antigens and alleles does HLA DP have?

Answer 25

6 antigens. 150 alleles.

Question 26

What percentage of England have HLA type A*24?

Answer 26

10.5%

Question 27

What is the percentage of HLA A*24 in Columbia?

Answer 27

26.2%

Question 28

What is significant about HLA B46?

Answer 28

This is 0% in most countries but 29% in Thailand. (10% in Japan)

Question 29

Who MUST have their HLA loci determined?

Answer 29

All potential organ recipients and donors so that rejection is minimised.

Question 30

What are Terasaki trays?

Answer 30

Plates used in HLA serology that contain serum with anti-HLA antibodies. A patients cells and complement are added and if the antibody reacts with patients sample then death occurs.

Question 31

What does the green dye show in a terasaki tray?

Answer 31

Live cells

Question 32

What does red dye show in terasaki trays?

Answer 32

Dead cells.

Question 33

What do ALL molecular methods of HLA typing require?

Answer 33

Require the extraction of high quality genomic DNA.

Question 34

What is used by NHS labs to carry out molecular HLA typing?

Answer 34

A semi-automated system that extracts genomic DNA from whole blood.

Question 35

Where else can genomic DNA be isolated from for HLA molecular typing?

Answer 35

Buccal swabs, Saliva samples, Fingernails.

Question 36

What is an SSP in molecular HLA typing?

Answer 36

Sequence Specific Primer (SSP). Often the first step.

Question 37

What is often the first step in HLA molecular determination?

Answer 37

SSP.

Question 38

What does a Sequence Specific Primer consist of?

Answer 38

Multiple PCR primers that are specific to known HLA polymorphisms (antigens/alleles). These are supplied in a kit.

Question 39

What does a SSP produce?

Answer 39

Specific amplicons are produced from PCR if the primers are complimentary to sample patient DNA.

Question 40

How many people have HLA-B27?

Answer 40

8%

Question 41

What are risks associated with HLA-B27?

Answer 41

Risk of ankylosing spondylitis (spinal inflammation) and other inflammatory disorders.

Question 42

What percentage of Ankylosing Spondylitis sufferres are HLA-B27 positive?

Answer 42

95%

Question 43

What disorder is associated with HLA-B57?

Answer 43

Drug induced inflammatory disorder.

Question 44

What two HLA types are patients screened for prior to UK treatment?

Answer 44

HLA-B27. HLA-B57.

Question 45

What is a major risk factor associated with hyperacute rejection?

Answer 45

Recipients may have antibodies to antigens that are expressed on donor cells.

Question 46

Where might anti-HLA antibodies develop from?

Answer 46

Pregnancy. Blood transfusion. Previous transplantation.

Question 47

What is a CDC crossmatch? When is it done?

Answer 47

Carried out right before surgery. Recipient sera is incubated with donor lymphocytes in the presence oof complement.

Question 48

What does CDC stand for?

Answer 48

Complement Dependent Cytotoxicity