HLI 2 Flashcards
(97 cards)
1
Q
List the steps in granulopoesis and what characteristic at each stage
A
1, myeloblast - large round cell, sphericle nucleus
- Promyelocyte
- Large cell, Azurophilic granules appear - Myelocyte
- Specific granules appear
- Mitotic ability lost - Metamyelocyte
- Nucleus becomes kidney shaped - Band - nucleu looks like a band
- segmented form
- Further maturation
2
Q
List 3 characteristics of immature granulocytes
A
1) stronger basophilic staining
2) larger cells
3) spherical or long nucleus
3
Q
what is lymph
A
- itself is a clear, slightly yellowish and opalescent fluid derived from blood.
- Lymph draining the small intestines is milky since it contains chylomicrons & lipids
- carrying WBC, high percentages of lymphocytes
4
Q
what are the 4 functions of the lymphatic system
A
- Controls blood & interstitial fluid volume
- Return excess filtered fluid and protein to blood - Specific transport systems
- Absorption of fat from gut
- (also lipid soluble vitamins eg A, D, E & K) - Turnover of extracellular matrix constituents
- glycosaminoglycans - Defense systems
- Immune surveillance
- Lymphocyte recirculation
5
Q
What are primary and secondary lymphoid organs and give some examples
A
Primary - where lymphocytes mature
EG - bone marrow, thymus, ileal peyers patches near ileocacecal junction (B cells), bursa of fabricius (B cells chicken)
Secondary - where mature lymphocytes reside
EG - lymph nodes, spleen, tonsils, caecal tonsils (birds), hemal nodes (ruminants)
6
Q
Variations of L.N between species
A
- Dogs and cats don’t have middle and caudal mediastinal
○ Pigs, horses and ruminants have a caudal mediastinal
○ Located between caudal lobes of the lungs - prominent - Dogs and cats don’t have subiliac (prefemoral)
○ Pigs, horses and ruminants do
○ Located in the hindlimb
7
Q
What are the two main lymphatic ducts in the body, what do they drain and where do they drain
A
1) The right lymph duct drains the right forelimb, shoulder area, and the right side of the head and neck.
2) The left lymph duct, or thoracic duct, drains everything else, including the hindlegs, GI tract and other abdominal organs, thoracic organs, and the left side of the head and neck and left forelimb and shoulder.
- These ducts then drain into the external jugular veins or subclavian veins on each side
8
Q
where is the cisterna chyli located
A
in the abdominal cavity
caudal to the diaphragm, dorsal to the aorta and ventral to the vertebral column
9
Q
Loose vs dense lymphatic tissue
A
Loose lymphatic tissue
Between lymphatic nodules; in medullary cords and deep cortex of lymph nodes
- Stroma contains a reticular network for support
○ Reticular fibres and cells (+ macrophages, lymphocytes)
Dense lymphatic tissue - aggregation of lymphocytes
10
Q
lymph nodes what are the characteristics of the cortex and medulla
A
CORTEX - More dense lymphatic tissue - Contain lymphatic nodules ○ Primary or secondary ○ Secondary have lighter staining centre - More B cells and cells in general in lymphatic nodules MEDULLA - More loose lymphatic tissue - Macrophages, T cells
11
Q
What are the general structure of lymphoid tissues - primary and secondary nodules
A
- predominantly B lymphocytes
○ primary nodules – resting
○ secondary nodules – activated - Secondary nodules form following
○ contain a germinal centre (become activated)
○ large, pale staining cells; mitotic figures
→ clonal expansion of B cells
12
Q
Bone marrow what are the two types and where are they found in adults
A
- Red marrow found in flat bones: skull, ribs, sternum, pelvis, vertebrae, heads of long bones
- Yellow marrow found in shaft of long bones
13
Q
What is the thymus divided into in pigs and sheep
A
- Cervical lobe
- Intermediate lobe
- Thoracic lobe
Full of adipose tissues
14
Q
Reticular epithelial cells where are they found and their function
A
- Direct the differentiation of T cells
• Thymic hormones – thymopoietin, thymosin α, thymulin - Cell contact – stromal macrophages
15
Q
Thymic (Hassall’s) corpuscles where are they found, characteristics
A
The medulla of the Thymus
– Large, eosinophilic
– Degenerate epithelial cells form clumps in the medulla.
– Keratinised centre surrounded by elongated epithelial cells
– Seen mainly in older animals post puberty
16
Q
Bursa of Fabricius
A
Found in birds
“Cloacal Tonsil”
Primary lymphoid organ for maturation and differentiation of B cells (Bone Marrow in mammals, Bursa in birds)
17
Q
Bursa of Fabricius
A
Found in birds
“Cloacal Tonsil”
Primary lymphoid organ for maturation and differentiation of B cells (Bone Marrow in mammals, Bursa in birds)
18
Q
What are Harderian glands, where are they found and list the structures of the Harderian gland
A
- chicken
- a pair, locates between the eye and the nasal cavity
- involved in the local immune responses of the conjunctivae and upper respiratory tract
- A central duct drains the gland secretion to the eye.
- play a role in terminal B cell differentiation and Ig class switch - PRIMARY LYMPHOID ORGAN
1. . capsule – thin connective tissue
2. lobes divided by septa
3. main ducts - compound tubuloacinar gland, unequal-sized tubular secretory units
- massive accumulations of lymphoid cells, majorly of plasma cells in the interstitium, particularly in the centre area of a lobule
19
Q
Differences between Hemal nodes and lymph nodes
A
Hemal nodes unique to ruminants
- no lymphatic vessels; no typical medulla
- sinuses filled with blood
- receive cells, antigens from blood, and after Ag stimulation, many nodules may form
- Functional significance of hemal node is not fully understood
20
Q
What are the two main sections of the spleen and how do the arteries branch into the spleen
A
White pulp - more white blood cells
Red pulp - more blood cells
Branches of the arteries in the spleen
splenic artery → trabecular artery → central artery
→ pulp artery → arteriole → capillary (remember)→ venous sinus (closed) or red pulp (open)
(a penicillus or penicillar arterioles )
21
Q
What are the two main sections of the spleen, other structures and how do the arteries branch into the spleen
A
1) White pulp - more white blood cells
2) Red pulp - more blood cells
Trabecular - smooth muscle and collagen fibres
Branches of the arteries in the spleen
splenic artery → trabecular artery → central artery
→ pulp artery → arteriole → capillary (remember)→ venous sinus (closed) or red pulp (open)
(a penicillus or penicillar arterioles )
22
Q
What are the two main sections of the spleen, other structures and how do the arteries branch into the spleen
A
1) White pulp - more white blood cells
2) Red pulp - more blood cells and smooth muscle present, more in ovine
Trabecular - smooth muscle and collagen fibres
Branches of the arteries in the spleen
splenic artery → trabecular artery → central artery
→ pulp artery → arteriole → capillary (remember)→ venous sinus (closed) or red pulp (open)
(a penicillus or penicillar arterioles )
23
Q
What are ellipsoids and structures
A
- (pericapillary macrophage sheaths) or sheathed capillary
- surrounded by concentric layers of macrophages contained in a reticular framework
- leaky capillaries found in the spleen
24
Q
what is the function of red pulp and are sinusoids present in the spleen
A
- Removal of deteriorating red cells and platelets
- Immune function: identification of antigens by macrophages and dendritic cells
sinusoids - present in dog but not other species (just leaky veins and venules) - lined by endothelial cells, free movement of blood, bound by rings of basement membranes with macrophages
25
What are the 3 locations of the tonsils and what epithelium covers them
1) lingual – base of the tongue
2) palatine – caudolateral to the tongue
3) nasopharyngeal – roof of the nasopharynx
covered by stratified squamous epithelium
26
Peyers patches where found, what cell is important and how distinguish between that cell and a normal epithelial cell
- Found predominantly in the ileum and at the ileocecal junction
- M cells within the epithelium cells, uptake and present antigens to lymphocytes within the peyer patches
○ No microvilli or brush boarder unlike epithelial cells
27
caecal tonsils where found, what are they
- Near junction of ileum and caecum
| Aggregates of lymphatic tissues
28
megakaryocyte where present, what cell might be confused for and function
present in the bone marrow and might be confused for an osteoblast
Function - responsible for the production of platelets and thrombocytes
29
Why is it important to know the type of poison used in rodenticide poisoning and what if don't know
For management of treatment
○ If third generation rodenticide - going to need 4-6 weeks of daily K1
○ If first generation - don't need to treat with daily K1 for as long
If don't know give for a few weeks then stop and wait 24-48hours do assays
30
If testing for poisoning and acute bleeds which test use and why
PT - prothrombin testing
tests function of the clotting factors in the extrinsic pathway where clotting factor 7 is. Clotting factor 7 has the shortest half-life and therefore will need to be replenished quicker in its active form and consequently will be decreased first and detected in lower functional levels first during Vit K antagonism
31
what is TT and the normal range
TT = thrombin time
- Time from when add thrombin to when fibrin clot forms
Very short 5-10seconds
32
Lymphadenomegaly what does local and generalised enlargement characterise
Local enlargement - reflects a pathologic process limited to the drainage area such as inflammatory or neoplastic disease
Generalised enlargement - more of a serious finding because it indicates a systemic disease or systemic neoplastic disease
- Don't grow themselves but get fluid with cells or tissues
33
Reactive hyperplasia of the lymph node, is it common, what does it look grossly and histologically
most common change observed in lymph nodes
- Reactive response to an immune stimulus generally from the area the lymph node drains
- Such as enzootic pneumonia leading to enlarged tracheo-bronchial lymph nodes
Grossly
- Lymph nodes are enlarges and mobile - if cut capsule cortex may expand and parenchyma bulges
Histology
•Increased germinal centres (=proliferation of B cells), plasma cells, macrophages
34
Describe a histological change in germinal centers of lymph nodes responding to injury
Starry Sky appearance of germinal center
| macrophages engulfing B cells that don't make it
35
List 5 causes of lymph node hypoplasia/atrophy
1. Lack of antigenic stimulation - animals raised germ free (SPF)
2. Cachexia - neoplasm or starvation - loss of T cells little effect on B cells
3. Aging - increased fibrous tissue - decrease T and B cels
4. Radiation - lymphocytolysis but restored if normal BM can supply
5. Viral infections - some target lymphocytes
36
lymphoid necrosis list 2 possible causes and what occurs microscopically and grossly
1. Equine Herpesvirus infection - target high turnover lymphoid tissue
2. Parvovirus infection of dog - necrosis of peyers patches, lymph nodes and spleen
Microscopically - lymphocytolysis with abundant karyorrhexis (fragmentation of the nucleus)
Grossly - not visible but lymph nodes could seem smaller
37
Pigmentation of the lymph nodes what does this suggest and characteristics grossly
lymphoid never produce the pigmentation - about where it is draining from
1. pigmented
2. cortex and medulla still distinct - REACTIVE
38
What are the 3 main reasons for lymphadenitis
1. “Reactive” lymph node (the LN is reacting to inflammation elsewhere, but free of local invasion; hyperplasia is the main change)
2. Inflammation (lymphadenitis) as result of direct infection
3. Lymphadenitis as result of drainage of infectious agents from infected site
39
grossly what does suppurative lymphadenitis and granulomatous and pyogranulomatous lymphadenitis look like
Suppurative lymphadenitis - friable consistency - necrotic center surrounded by macrohpages
Granulomatous and pyogranulomatous lymphadenitis - architecture gone
- Fibres tissue surrounds and contracts the infection - tries to wall off
40
List 2 main causes of suppurative lymphadenitis - primary inflammation
1) porcine jowl abscess
| 2) equine strangles (strep. equi) - enlarged submandibular lymph nodes
41
List 2 examples of secondary (indirect) infections of the lymph nodes that cause lymphadenitis and describe
Chronic granulomatous lymphadenitis
1) Bovine Tuberculosis - mycobacterium bovis (cattle)
- Lost corticomedullary junction
- Finds it hard to deal with, macrophages struggle killing them
○ End up with granuloma walled off with fibrous tissue - Lesions are caseous and often mineralised
2) FIP - feline infectious peritonitis - key finding is vasculitis leading to thrombosis and infarction - can look like lymphoma - has high protein and most likely to infect cats in stressful environments
42
neoplastic disease of the lymph node what is their main characteristics and describe the 4 types
ALWAYS MALIGNANT NEVER BEIGN
1) Lymphoma is the most important
- Lymphoid proliferation arising from neoplastic transformation of lymphoid cells outside marrow tissues
2) Carcinoma - tend to metastasise regional lymph nodes through lymphatics first then lungs
3) Sarcoma - venous system straight to the lungs
4) Leukaemia - lymphoid proliferation arising from neoplastic transformation of lymphoid cells in the bone marrow
43
List character
1) no normal architecture left
2) high grade of mitotic figures
2) monomorphic populations of certain cells
3) giant cells
44
hypercalcemia of malignancy what occurs in response to
- Common paraneoplastic syndrome in canine and feline lymphoma
- Hypercalcemia may occur owing to resorption of bone resulting from the paraneoplastic syndrome
- may be due to neoplasm of lymph nodes
45
canine lymphoma how common, what age, characteristics
- Most common canine hematopoietic neoplasm
- Often middle-aged and older
- Most have multicentric distribution with a generalised lymph node involvement
- Most are B cells that are aggressive and rapidly growing other are T cell, alimentary, cutaneous and mediastinal
46
feline lymphoma how common, what type of cell and the types within
most common of cats
Enteropathy-associated T cell lymphoma - subdivided into type 1 and type 2 and most commonly found in the jejnum
Type 1 - composed of large T cells and abundant tissue necrosis with poor prognosis
Type 2 - composed of small T cells with little tissue necrosis and slow growing
47
feline leukaemia how common and give example of what can cause it
leukaemia and bone marrow involvement are common in all forms
Feline leukaemia virus - oncogenic retrovirus that often affects young cats and most commonly leads to mediastinal or multicentric T cell lymphoma
48
Equine lymphoma how common in what form, what cell involved and other forms
- Lower incidence than in cats, cattle and dogs
- Multicentric lymphoma is the most common form
- Usually T cell rick large B cell lymphoma
Can be alimentary with involvement of large intestines or cutaneous
49
bovine lymphoma what form, what causes it and what are the 3 forms
Enzootic - multicentric disease of adult cattle
- Agent is bovine leukemia virus (BLV) an oncogenic retrovirus
- Virus is transmitted by transfer of viral infected lymphocytes
3 forms
1. Calf form - birth - 6 months,
2. Juvenile/thymic - less than 2 years,
3. Cutaneous - 2-3 years old
50
List 5 characteristics to classify lymphomas
1) •Anatomic location - intestinal in cats often
2) •Immuno-phenotype (IHC) - B cell or T cells tumour
3) •Cellular morphology
4) •Histologic pattern
5) •Biologic behaviour (staging) - is it in other tissues or viscera
51
how to know if lymphoma or B or T cells
Immunohistochemistry - stains antigens in the capsule
52
what are the 6 main pathologies of the spleen
1. Degenerative disease
2. Circulatory disturbances
3. Splenitis
4. Hyperplastic disease
5. Neoplastic diseases
6. Splenomegaly
53
what are the 5 degenerative diseases of the spleen, are they important and cause
1) splenic lymphoid necrosis - parvovirus, BVD, EHV-4
2) siderotic plaques - incidental, common old age dogs
3) haemosiderosis - old age, can be inceased with haemolytic anaemia
4) splenic atrphy - older animals or cachexia and starvation
5) splenic contraction - grossly looks like infarct but just expulsion of blood - good
54
what are some causes of splenomegaly
1) Some anaesthetics can cause blood to pool in the spleen
2) Horses can get very enlarged and splenic contraction is important
3) Gastric Dilation Volvulus - twisted around, veins get blocked off however arteries continue to pump blood within therefore enlarged - emergency
○ Cyanotic as erythrocytes have lost oxygenation
55
splenic infarcts when occur, characteristics acute and chronic
- If spleens are enlarged for any reason are prone to thrombosis and infarction - neoplasia
ACUTE
Swells above level of the capsule
- Dark red
CHRONIC
- Fibrous tissue comes in contracts down below capsule
- Change from dark red to grey/white as the lesion becomes organised
- End up with a defect
56
splenic rupture what causes and when more likely to occur, consequences
Trauma is the most common cause especially in dog
○ Needs to be very traumatic if normal spleen
○ If congested or haematoma just need mild trauma
Leads to severe blood loss and possible death from hypovolemic shock
57
Splenic volvulus torsion when occur and gross appearance
- Occurs mostly in pigs and deep-chested dogs - gastric dilation volvulus
- Twisting of the spleen around the gastrosplenic ligament resulting in occlusion of vein leading to splenic congestion and infarction
- Grossly - enlarged, cyanotic and may be folded back on itself and C shaped
58
what are the 3 types of splenitis
* Acute (congestive splenitis)
* Suppurative splenitis (acute or chronic)
* Granulomatous splenitis (chronic)
59
List 2 things that can cause acute splenitis
1) anthrax
| 2) african swine fever
60
give an example of a disease that leads to Chronic suppurative splenitis
Caseous Lymphadenitis in sheep - also in lymph nodes
61
what are the 4 hyperplastic diseases of the spleen
* Follicular (white pulp) hyperplasia
* Nodular hyperplasia
* Hyperplasia of the Monocyte-macrophage system
* Extramedullary haematopoiesis - meaty due to extra cells
62
describe grossly follicular and nodular hyperplasia
follicular - generally systemic, nodular white follicles - white pulp
Nodular - white or red (if blood is trapped - can lead to haematomas) - common in old dogs
63
List 6 neoplastic diseases of the spleen
1) Haemangiosarcoma
2) Lymphoma
3) Histiocytic sarcoma
4) Mast cell tumors - important for cats
5) Sarcomas (other)
6) Metastatic tumors (carcinoma, sarcoma)
64
Haemangiosarcoma grossly, histology and characteristics
GROSS
- Dark red to black
- Pale areas - necrosis and eventually fibrosis
- Enlarged spleen with blood filled nodules prone to rupture
HISTOLOGY
- heaps of RBCS and schistocytes - shear stress of RBCS as the vessels are damaged
CHARACTERISTICS
- Often metastasise to the lungs and right auricle and any visceral structures like the liver
- Frequent in dogs and arises from vascular endothelium - german shepherds and goldern retrievers
- common location spleen and right atrium of the heart
65
lymphoma and mast cell tumour gross appearance and characteristics
lymphoma either nodular or diffuse (splenomegaly (pink))
Mast cell tumour
- Primary splenic mast cell tumour occurs mostly in cats
- Spleen is enlarged with a meaty texture
- Widespread metastasis is common
66
histiocytic sarcoma what cells involved and characteristics of those cells
- Macrophage or dendritic cell origin
- Epitheliod cells = look like epithelial cells - NOT JUST A MACROPHAGE
CHARACTERISTICS - - Multinucleated cells, pleomorphic and atypical cells
can present as a single nodule or mass
67
lymphoma and mast cell tumour gross appearance and characteristics
lymphoma either nodular or diffuse (splenomegaly (pink))
Mast cell tumour
- Primary splenic mast cell tumour occurs mostly in cats
- Spleen is enlarged with a meaty texture
- Widespread metastasis is common
68
histiocytic sarcoma what cells involved and characteristics of those cells
- Macrophage or dendritic cell origin
- Epitheliod cells = look like epithelial cells - NOT JUST A MACROPHAGE
CHARACTERISTICS - - Multinucleated cells, pleomorphic and atypical cells
69
splenic sarcoma what cell type, grossly and histologically
Primary sarcomas in spleen that arise from smooth muscle trabeculae (leiomyosarcomas) or fribroblasts (fibrosarcoma) as well as other types
GROSSLY - large tumours with firm consistency
HISTOLOGICALY - dominated by spindle cells, varying with necrosis
Can metastasise to the liver and other abdominal viscera
70
what are the 3 main disease processes of the thymus
1. Atrophy/hypoplasia
2. Inflammation - thymitis - rare and associated with other causes of inflammation in lymphoid organs
3. Neoplasia - thymomas and thymic lymphomas
71
differences between thymoma and lymphoma (of the thymus) and what is similar
thymoma - malignant epithelial cells with benign lymphocytic component, slower growing - rarely metastastise, assoicated with paraneplastic syndromes
Lymphoma other way around
SIMILAR - both thymic lyymphomas and thymomas occupy the mediastnum
72
reactive lymphoid hyperplasia describe the cytology findings
Key finding - a mixed population of lymphocytes with mild increase in intermediate lymphocytes, plasma cells and large lymphocytes
- normal lymph node architecture
73
What are the 4 types of hypersensitivity and characteristics of each
1. Type I hypersensitivity
• IgE (rarely IgG)
• Immediate
• Anaphylaxis
2. Type II hypersensitivity
• Cytotoxic (IgM, IgG Cell-Ag )
• Damage results when the humoral immune system ie Ab become directed against self.
3. Type III hypersensitivity
• immune complex • Ag-Ab to form immune complexes
• Large volume viral infections
4. Type IV (delayed-type) hypersensitivity
• T cell-mediated immune
• orchestrated by CD4+ or CD8+ T cells, depending on the nature of the target antigen.
74
Type 1 hypersensitivity
IgE mediated - must have IgE on the mast cell prior to contact with the allergen - therefore need to have been exposed to the allergen previously
75
Type 1 hypersensitivity
IgE mediated - must have IgE on the mast cell prior to contact with the allergen - therefore need to have been exposed to the allergen previously
76
What receptors are found on mast cells, dendritic cells and basophils that bind to IgE
FCƐ receptor
77
What is needed for hypersensitivity to occur and what results in the activation
- Need lots of IgE on the mast cell or basophil- high density IgE receptors
- Fc receptors on the surface are slightly different in terms of specificity for IgE which are specific for allergens (antigens)
- Multiple IgE's present on the mast cell that recognise different allergens
Activation of FCƐ receptor results in
1. Switch on gene expression for cytokines
2. Release of cytokines, histamine, lipid mediators - degranulation
Constriction of smooth muscle, vasodilation etc. - described below
78
Give an example of 3 types of chemicals released from eosinophils
1) Stored within granules
- Peroxidase - degrades helminthic and protozoan cell wall
- Tissue damage/remodelling
2) Major lipid mediators
- Leukotrienes - prolonged bronchoconstriction, mucus secretion, increased vascular permeability
3) Cytokines produced on activation
- IL-3, 5 - eosinophil production and activation
79
What are the 2 functions of eosinophils and granules that cause these
1) Killing of parasites and host cells
- Cationic granule proteins
2) Tissue remodelling
- Enzymes - eosinophil peroxidase
80
What are the 2 main tests used for determine the cause of an allergen
1) Skin testing - most effective
| 2) IgE Assays - IgE in blood very small concentration as most bound to the mast cells - not great
81
what is the aim of drug therapies with hypersensitivity reactions
inhibiting mast cell mediator production and at blocking or counteracting the effect of release mediators on target organs
- Prevent or reduce TH2 cells responses to specific allergens and the production of IgE
82
List 5 different drug therapies used for hypersensitivity reactions
1) corticosteroids are potent anti-inflammatory agents
2) adrenaline
3) histamine H1 receptor antagonists
4) leukotriene receptor antagonists
5) desensitisation - long-term solutions
83
List 4 reasons that some individuals are more susceptible to allergies than others
1) favour IL-4 (promotes TH2 and IgE response) - increased IL-4 produced, receptor expression
2) high affinity IgE receptor - increased number of mast cells
3) MCH II - enhanced presentation of allergic peptides
4) TH2 response preferred to TH1
84
In general what organs are most effected with anaphylactic shock with dogs and horses/cattle
Dogs - attack the liver and cephalic vein
| Horses/cattle - digestive tract, respiratory
85
List 4 treatment options for anaphylatic shock
1. Remove source allergen
• Remove stinger to minimise amount of venom
2. Apply ice to reduce swelling (20 min) if in skin and not ingested or inhaled
3. If anaphylactic reaction adrenalin administration
4. IV Fluid therapy & oxygen
86
What are involved with bee stings
Have multiple agents that have different reactions
1) mellitin
2) induces phospholipase A2 that destroy blood cells, lower BP, main cuase pain
3) phospholipase A
4) Histamine
87
What are involved with bee stings and list 4 chemicals
Have multiple agents that have different reactions
1) mellitin - main
2) induces phospholipase A2 that destroy blood cells, lower BP, main cuase pain
3) phospholipase A
4) Histamine
88
Type II hypersensitivity what mediated by and effector mechanisms
Mediated by circulating antibodies which react with a cell bound antigen
Effector mechanisms -
• Complement (MAC (membrane attack complex) or C3b)
• NK (ADCC) - antibody dependent cell mediated cytotoxicity - phagocytosis of antibody-coated cells can be destroyed by NK cells through attachment via Fc receptors
• Ab acting as opsonin enabling phagocytic cells to act directly with their Fc receptor to bind and phagocytose coated cells
89
Why do transfusion reactions occur, what type of hypersensitivty reaction
```
Transfusion to genetically dissimilar animal results in transfusion reaction (immune response)
• Rapid elimination of transfused blood
- Agglutination - clotting and clumping
- Haemolysis - destruction
- Opsonization by phagocytes
Type II hypersensitivty
```
90
List 8 clinical consequences of blood transfusion reactions
1) massive haemolysis
2) complement activation
3) circulatory shock
4) hypotension
5) apnoea
6) bradycardia
7) blood clotting
8) hypothermia
91
Give examples of Type II hypersensitivity reactions
Examples
- transfusion reactions
- drug allergies
- haemolytic disease of newborn
- transplant - graft vs host
92
What is involved with haemolytic disease of the newborn
- newborns inherit red cells from sire that isn't present in mother
- mother sensitised to this Ag via leakage of RBC by transplacental haemorrhage
- mother Ab crosses the palcenta or colostrum to the offspring resulting in anaemia
93
What is involved with neonatal isoerythrolysis in foals and kittens
Both appear healthy at birth and onset of clinical signs from 5h to 7 days and vary
Foal
- exposure of the mare to these antigens during a previous pregnancy or whole blood transfusion leads to the mare producing alloantibodies to the foal's red blood cells that it inherits from sire
○ After foal nurses colostrum antibodies a hemolytic anemia develops in the foal.
- Therefore need to put muzzle on the foal to prevent suckling and give other colostrum
Kittens - Due to high levels of antibodies against type A blood if type B therefore even the 1st pregnancy is a risk if the kitten has different blood type from the mother
94
List some clinical signs of neonatal isoerythrolysis
Clinical or subclinical signs depend upon the degree of haemolysis
• Foals with NI usually become progressively lethargic, weak, seizures and depressed.
• Mucous membranes may become pale and later icteric (jaundiced.) - chronic
• Adaptive changes to the anaemia such as tachycardia.
95
At what PCV should you give a transfusion
Anemia, PCV < 20 %/15%
96
What occurs with Type II hypersensitivity reactions against drugs
- Some penicillins attach to RBC and modify them resultign in them recognised as foreign resulting in sensitisation of the immune system
- later administration of penicllin may result in complement activation
97
What is Type III Hypersensitivity mediated by, what occurs
Immune complexes - typically formed in response to viruses
- Large quantities of poorly catabolized insoluble intermediate-sized immune complex
○ Due to overproduction of IgG and IgM to a foreign or self-antigen
- Large quantity of antigens, antibody complexes overwhelming the breakdown capability
○ Once cannot be broken down started to form precipitate out - lodge in vascular beds (below)
• Deposit in tissues & small blood vessels due to molecular size
