Type II Hypersensitivity

Question 1

Type II hypersensitivity is also known as _____________ hypersensitivity

Answer 1

Cytotoxic

Question 2

What are the three main diseases that cause Type II Hypersensitivity reactions?

Answer 2

1. Transfusion reactions
2. Hemolytic disease of the newborn
3. Reactions to drugs or infectious agents

Question 3

What species has the most diverse blood system?

Answer 3

Cows- 11 blood groups

Question 4

What species has the least diverse blood system?

Answer 4

Cats- 1 major blood group

Question 5

True/False: Antigens are MHC molecules

Answer 5

False!!

Question 6

Describe the typical antigen
membrane-bound or soluble?
composition
function

Answer 6

Most are surface antigens, some are soluble
Most are glycoproteins or associated glycolipids
they serve to transport different molecules

Question 7

What are natural antibodies? How are they generated?

Answer 7

Antibodies to blood group antigens that are not expressed in that individual and that they have never been exposed to.

Question 8

Why are natural antibodies of concern in transfusion medicine?

Answer 8

If exposed to antigens of this type, a transfusion reaction will occur either against the host or against the donor blood.

Question 9

How can drugs and immune clearance of infectious organisms induce a Type II hypersensitivity reaction?

Answer 9

immune clearance- antibodies againts infectious organisms can also croos react with RBC antigens
drugs- bind/absorb onto RBC and then are seen as foreign; can activate complement resulting in a destructive immune response against RBCs

Question 10

What type of T helper cell response is involved with an antibody response?

Answer 10

Th2

Question 11

What two types of mechanisms are associated with Type II Hypersensitivity?

Answer 11

1. Complement mediated lysis

2. Cell-mediated killing

Question 12

In HDN/NI, what three mechanisms sensitize the mother to foreign red blood cells?

Answer 12

1. Leakage of fetal RBC across the placenta
2. Previous receipt of an incomplete transfusion
3. Development of cross reactive antigens

Question 13

Where are antibodies against fetal RBCs concentrated?

Answer 13

Colostrum

Question 14

What happens when a foal receives anti-RBC antibodies in the colostrum?

Answer 14

Antibodies cross the GI mucosa and begin to attack neonatal RBCs-> rapid onset of hemolysis

Question 15

What is neonatal thrombocytopenia?

Answer 15

similar to HDN/NI, except the antibodies are against platelets and not red blood cells

Question 16

What antibodies is usually present with transfusion reactions?

Answer 16

IgM

Question 17

What usually happens with a first-time transfusion reaction?

Answer 17

antibodies will be generated against the red cells over time. Transfused red blood cells will circulate until antibodies are developed and then the cells will undergo antibody mediated destruction

Question 18

What are two methods to prevent transfusion reactions?

Answer 18

1. Blood typing

2. Cross matches

Question 19

What is agglutination?

Answer 19

Agglutination is grape-like clustering of erythrocytes to antibody crosslinking

Question 20

Which antibody is good at agglutination and which is not?

Answer 20

IgM-good

IgG-bad

Question 21

What is blood typing?

Answer 21

This is performed by mixing washed RBCs from a patient with species specific antiserum (antibodies). If the antiserum cross reacts with the patient RBCs, RBCs will agglutinate.

Question 22

What is a major cross match? What is a minor cross match?

Answer 22

Major Cross Match- donor cells with recipient serum. Detects antibodies in the animal that can react against transfused blood.

Minor Cross Match- recipient cells with donor serum
Detects antibodies in the donor blood that can react against the donor blood

Question 23

Match the species with the most clinically relevant blood group system
Cat                           A&Q
Cow                         B&J
Dog                          B&R
Horse                      DEA 1.1
Pig                           A&O
Sheep                      AB

Answer 23

Cat-AB
Cow- B&J
Dog-DEA 1.1
Horse- A&Q
Pig- A&O
Sheep- B&R

Question 24

Mix and Match
Cat Every one has unique blood panel
Cow Minimal donor-1.1 negative
Dog One RBC Ag is K+ porter
Horse HDN/NI assoc w/ RBC in vaccines
Pig One blood group system
Sheep HDN/NI very common

Answer 24

Cat- One blood group system
Cow- Every one has unique blood panel
Dog- Minimal donor- 1.1 negative
Horse- HDN/NI is very common
Pig- HDN/NI associated with RBC in vaccines
Sheep- One RBC Ag is K+ porter