Hypersensitivity 2 Flashcards

1
Q

Define a hypersensitivity type 2 reaction

A

Destruction of normal tissue/cells by antibody (IgG or IgM)) with activation of complement or antibody dependent cell cytotoxicity (using NK cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Common examples of type 2 hypersensitivity reactions

A

Blood transfusion reactions
Hemolytic anemia of newborns
Penicillin induced anemia
Some autoimmune diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why are red blood cells commonly affected in type 2 hypersensitivity reactions?

A

They do not display MHC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Transfusions are performed with

A

Blood loss
Trauma
Surgery
Low RBC count

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How high is the risk of a reaction to a blood transfusion

A

Species dependent because some species are able to receive one “free” transfusion without a risk of reaction (body has no antibodies/it was never sensitized to another blood type)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is ACD (acid citrate Dextrose) solution used for?

A

Blood collection as an anticoagulant and energy source for RBCs

Often in human blood collection packs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the formula for ACD solution?

A

Trisodium citrate 22.0g
Citric acid (monohydrate) 8.0g
Dextrose (monohydrate) 24.6g
Distilled water to make up to 1L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

For each 100ml of blood collected, you need _____ ml of ACD solution (pH 5.0)

A

15ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Blood group antigens: name often starts with a species code and EA (erythrocyte antigen) followed by a letter or number denoting the order of discovering, what is DEA 1.1

A

DEA: dog erythrocyte antigen 1.1: first allele of antigen 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A recipient of a blood transfusion may contain pre existing antibody as a result of?

A

Previous blood exposure or exposure through the diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The risk of dietary exposure to a blood group antibody is species dependent
Who is it often seen in and why?

A

Cattle and some cats

Due to ingesting colostrum with antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the mechanism behind a blood transfusion reaction

A

Pre-existing antibody binds to the erythrocyte antigens and activates a complement reaction causing:

Hemolysis

Anaphylatoxin release and mast cell degranulation

Free hemoglobin (can cause secondary damage to the kidneys)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How are transfusion reactions prevented

A

Cross matching

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe major cross matching

A

Using the donor’s RBCs and the recipients serum

Look for lysis (complement) and agglutination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Minor cross matching

A

Donor serum and recipient RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Signs of a mild to moderate transfusion reaction

A

Sweating, salivation, diarrhea, vomiting, increased RR/HR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the signs of a severe transfusion reaction?

A
Shock 
Weakness
Hyperpnea
Hypotension 
Collapse 
Death (arrhythmia or apnea)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the signs of the recovery phase of transfusion reactions?

A

Hemoglobin from ruptured RBCs eventfully converted to bilirubin

Icterus (yellowing) of mucosae and sclera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe blood transfusions in cattle

A

MANY blood types
Blood typing used to check parentage
Transfusions are often incompatible

Some cattle have pre-formed antibodies against foreign RBCs often due to dietary antigens

First transfusion last days to a week

Repeated transfusions needed for the shorter life of RBCs

20
Q

Dogs have no preformed antibodies against foreign RBCs, they do have many RBC antigens though, what is the major antigen in dogs that causes most problems with transfusions

A

Only one group DEA 1 (strong antigen) there is a card to test this antigen

DEA 1.1 is a subgroup and the major cause of concern with DEA 1 dogs

40% of dogs are DEA 1.1 positive. They can receive blood from DEA positive AND negative dogs, making them universal blood recipients

21
Q

if DEA 1.1 (and ideally 1.2) positive dogs are universal recipients, what does that mean for DEA 1.1/1.2 negative dogs

A

Universal blood donors (don’t need to worry about most dangerous group of antigens)

Greyhounds are universal donors bc most are DEA negative

22
Q

What happens when you transfuse a DEA 1.1 negative dog with a DEA 1.1 positive dog

A

First transfusion is a “freebie” - it will be okay bc there is no preformed antibodies but the body will start to make new antibodies for the next exposure

Transfusion reactions will be seen on subsequent transfusions

This is a common problem in puppies (neonatal isoerythrolysis)

23
Q

Recommended that you always _____ on subsequent transfusions in breeding bitches

A

Cross match

24
Q

Does antigen testing for strong antigens prevent:

A

Problems on first transfusions: yes

Problems on subsequent transfusions:
yes (small risk of incompatibilities from minor antigens)

25
Q

Does cross matching first transfusion prevent problems with:

A

First transfusions: yeas (test to see if recipient has antibodies to that blood)

Subsequent transfusions: no (you don’t know the blood type, and it doesn’t mean you can use the same blood from the first transfusion because it could have been sensitized from the first transfusion)

26
Q

T or F

Cross matching tell you the blood type of the animal

A

FALSE

it tells if the recipients blood will react to the donors serum

27
Q

Antigen testing tells you what

A

Blood type

28
Q

Describe transfusions in horses

A

Many blood groups but only 2 are important

No preformed antibody unless previously exposed (one free transfusion)

Risk of reactions is like dogs except multiparous pregnant mares have a higher risk

29
Q

Describe blood transfusions in cats

A

Low incompatibility risk in North Americans domestic cats

Transfused RBCs last about 5 weeks

30
Q

Describe the blood groups of cats

A

Follow and non standard system
There is one gene with 3 alleles

A is dominant and gives blood type A

B is recessive, BB cats are type B blood

C is rare and gives type AB blood

99% of all North America domestic cats are the same blood type (A)

Siamese and Burmese - all type A

Persian and Himalayan are mixed, either A or B

UK cats: 40% are type A and 60% are type B

31
Q

Most cats possess IgM antibodies against type A antigens even though no previous transfusions probably due to

A

Dietary antigens

32
Q

A blood transfusion to a type B from a type A cat is destroyed in?

A

Hours

33
Q

Some type A cats possess low amounts of antibody against Type B antigens, resulting in?

A

Less sever transfusion reactions

34
Q

What is neonatal isoerythrolysis (AKA hemolytic disease of newborns)

A

Results from ingesting colostrum rich with antibodies against the neonates RBCs (antibody causing the problem is passively transferred)

Common problem in horses and mules

Occasionally seen in cats, dogs, and sheep

35
Q

Describe how neonatal isoerythrolysis occurs in horses, foals, and mules

A

Occurs when:

  • stallion has a different blood group (antigens) from the mare
  • foal inherits some antigens from the dad therefore has a different blood type from the mare

Aa and Qa antigens cause the most problems (others are weaker)

Dam is sensitized due to leakage of foal blood from placental bleeding or at foaling during previous transfusions and starts to make antibodies

Foal ingests colostrum from the mare that has antibodies against its blood type

36
Q

What breed of horses is neonatal isoerythrolysis common in

A

Thoroughbred mares that have had multiple foals

Affects 1% of foals

37
Q

Describe how a mule is created

Can it be the reversed situation?

A

Mule: female horse and male donkey cross (large genetic difference making them sterile) there is a 10% rate of neonatal isoerythrolysis occurring with the birth of mules

Very rare in reverse (male horse and female donkey) very unlikely it will survive - if it does = a Hinny

38
Q

What are the signs of hemolytic anemia when the foal ingests colostrum with antibodies

A

Initially pale and then icteric mucous membranes

May show hemoglobinuria

Weakness
Lethargy
Shock
Death

39
Q

How do you test for neonatal isoerythrolysis

A

PCV (mild: 0.15 to 0.25 L/L)
(severe: <0.25 L/L)

Jaundiced foal agglutination test:
mare’s colostrum with foal’s RBCs (agglutination is positive)

Test mares blood during pregnancy for rising titers of antibodies against Aa or Qa antigens

40
Q

How is neonatal isoerythrolysis treated?

A

Prevent or stop colostrum ingestion for at least 36hr (colostrum production will stop and give time for foal to correct anemia and make more RBCs)

Feed colostrum to from another mare (best option) or give serum from an unrelated horse

Blood transfusion if PCV <0.15 L/L ((convenient source is washed RBCs from the dam (takes out serum))
equine RBCs clump and separate from serum with time - making this easy

41
Q

Describe neonatal isoerythrolysis in cats

A

AKA Fading Kitten Syndrome

Rare in NA more common in UK

Most likely seen when a blood group B queen is mated with a blood group A tom

Chance of this occurring is small if the queen is A and tom is B

42
Q

Describe how neonatal isoerythrolysis occurs in cats

A

Blood type B queen x blood type A tom

Queen with genotype bb
Tom will be genotype ab or aa

Offspring will be”

1) if tom is ab: ab or bb (type a or b)
2) if tom is aa: ab (type a)

Blood group A offspring at risk of this disease from the A antibody in colostrum

43
Q

Signs of Fading Kitten Syndrome

A

Icterus
Weakness
Paleness

44
Q

Describe type 2 drug hypersensitivities

A

Drug or its breakdown products bind to cells making them antigenic (labels cells as pathogenic and the body attacks them)

45
Q

Penicillin associated hemolytic anemia is rare but occasionally seen in

A

Horses

46
Q

Describe vaccines grown in tissue

A

Cattle killed BVD vaccine is grown on kidney cells

Contains potent adjuvant (causes an increased immune response)

Causes stimulated anti MHC antibody production

Antibody transferred to calves in colostrum and causes pancytopenia