Lecture 23 - Histocompatibility

Question 1

What is HLA nomenclature

Answer 1

DR B1 * 15:03

DR= DR antigen
B1= B1 gene
* = molecular typing
15= antigen serologiacally defined as DR15
03=third allele described

Question 2

What is the serological typing of DR B1 * 15:03

Answer 2

DR15

Question 3

Where are HLA genes located

Answer 3

the short arm of chromosome 6

Question 4

What are the main HLA antigens

Answer 4

A, B, C, DR, DQ. DP

Question 5

What autoimmune disease are associated with HLA

Answer 5

• celiac disease
• type 1 diabetes
• MS
• Ankylosing spondylitis

Question 6

What drug sensitivities are associated with HLA

Answer 6

• abacovir
• carbamazepine

Question 7

What are the class I HLA

Answer 7

A B C

Question 8

What are the class II HLA

Answer 8

DR DQ DP

Question 9

What were the traditionally typed antigens in solid organ transnsplantation

Answer 9

A C DR

Question 10

How are HLA typings done traditionally

Answer 10

• serological CDC methodology using lymphocytes
• lymphocytes are isolated and tested against numerous anti sera
• ~300 sera required for full typing

Question 11

How does complement dependent cytotoxicity work

Answer 11

• lymphocytes are incubated with serum
• rabbit complement initiates cell lysis when antibodies have attached
• cell lysis/death is observed

Question 12

What are the molecular methods for HLA typing

Answer 12

1. SSP
2. Reverse SSOP
3. qPCR
4. Sequencing based typing
5. Oxford nanopore

Question 13

What is the SSP technique

Answer 13

• primers specific for every allele of interest must be included

Question 14

What is reverse SSO

Answer 14

• loci are amplified and probes are used to detect alleles
• uses a luminex instrument for read out
• can run in batches or single samples

Question 15

What is the reverse SSO method workflow

Answer 15

• isolated DNA is amplified
• DNA is amplified with HLA locus specific primers
• PCR product is biotinylated
• PCR product is incubated with probe labelled beads
• streptavidin labelled conjugate is added
• fluorescence is measured

Question 16

What are benefits of molecular methods

Answer 16

• does not required viable lymphocytes
• age of specimen and conditions of transport are less important
• easier to create a primer than find antisera
• DNA samples are easily stored for repeat testing
• higher resolution typing can be performed
• potential for automation
• less subjective readings

Question 17

What are disadvantages of molecular methods

Answer 17

• lymphs are still necessary for crossmatch
• potential DNA contamination demands stringent lab set up
• rare null alleles will be detected by DNA but not expressed on the cells
• new alleles are always being identified so software must be frequently updates