HLI 5 Flashcards
List 8 hallmarks signs of immunodeficiency
1) disease affecting particular breed
2) disease occurring in young littermate animals with onset shortly after the expected time of loss of maternally derived immunity
3) Chronic recurrent infections
4) Infection of multiple body sites
5) Failure of infection to respond to antimicrobial therapy.
6) Infection with environmental saprophytes (e.g. Aspergillus, Pneumocystis) - most healthy animals don’t get sick from these
7) Persistent lymphopenia or hypogammaglobulinaemia.
8) Failure to respond to vaccination
Give an example of a inherited defect in innate immunity, what seen, clinical signs and breeds
Pelger Huёt Anomaly
- Quite common in the breeds
- Reduced segmentation of granulocyte nuclei
- NO toxic change - well mature
- No functional disorders identified, incidental finding - healthy animals
- Australian shepherd dogs, American foxhound, other breeds and cats
Give an example of a inherited defect of the acquired immune system, what animals, what lead to and why
Severe Combined Immunodeficiency (SCID) -
- Arabian horses and Jack Russell terriers
- Autosomal recessive
- Mutation of gene coding DNA-protein kinase
- Can’t rearrange VDJ chains to form T and B cell receptor
○ Cannot detect many antigens
- Lymphopenia & lymphoid hypoplasia
- Foals die 2- 6 months despite care
- Lack of serum IgG and IgA
Selective Immunoglobulin Deficiencies, when see clinical signs what are the 3 main ones, what animals found in and how to diagnose
Clinical signs after decrease of maternal immunity
1) IgA deficiency- Dogs ((German shepherd) - increase mucosal infections
2) IgG deficiency
3) IgM deficiency - foals
Total globulin levels won’t be abnormal so to diagnose may need to do a serum electrophoresis
List 5 acquired or secondary defects of the immune system
1) Retroviruses - FIV and FeLV, Koala retrovirus
2) Drugs
a. Chemotherapy
b. Corticosteroids
c. Immunosuppressives – cyclosporin, azathioprine
3) Malnutrition
4) Irradiation
5) Ageing
Feline Immunodeficiency virus (FIV) what occurs, how transmitted and the 4 stages of the infection
- Progressive decline in CD4+ T lymphocytes
- Transmitted via bite wounds (blood/saliva)
Acute phase - Mild illness, lymphadenopathy
- CD4 levels reduce
Asymptomatic Phase - Healthy but CD4 levels continue to decline over months to years
Progressive or recurrent illness - lymphadenopathy, weight loss, leukopenia
Terminal phase - Chronic multi-systemic disease
- Neoplasia
List 3 main and factors within promoting autoimmune diseases
1) Genetics – MHC, IgA deficiency
2) Environmental factors
○ Infections
○ Drugs – e.g. TMS
○ Vaccines
○ Diet
3) Reduced function of natural T-reg cells permits activation of auto-reactive T cells and B cells - against self-antigens
Give an example of an autoimmune disease what occurs and clinical signs
ystemic Lupus Erythematosus (SLE)
- Failure of mechanisms that maintain immunological self-tolerance
- Production of autoantibodies against nuclear and cytoplasmic components of the cell -> Autoantigen-antibody complexes deposit throughout the body→ type III hypersensitivity reaction → inflammation of joints, skin, and kidney
Clinical signs
- variable, organs affected are unpredictable
- Lethargy, anorexia, fever of unknown origin
- Haemolytic anaemia, thrombocytopenia, bone marrow necrosis
dermatitis,
Type II Hypersensitivity Autoimmune Disorders what are the 3 steps
- Antibody against self-antigens leads to the following:
- Complement-mediated destruction
- cytotoxicity from NK cells
phagocytosis from macrophages
List 3 immune-mediated haematologic disorders
1) Immune mediated haemolytic anaemia
2) Immune mediated neutropenia
3) Immune mediated thrombocytopenia
In flea allergy dermatitis what are more effective corticosteroids, anti-histamines or NSAIDS and why
Coricosteroids are more effective
Antihistamine
- Prevent binding of histamine to the receptor
- Not stopping the production and action of other molecules
NSAIDS
- Inhibits prostaglandins - decrease vasodilation and sensitisation of nerves for itching
Not decreasing IgE production or T cell activation
List the 4 ways infectious agents enter the skin and skin examples
1) through epidermal barrier
- UV light, infections
2) through adexal barrier - rupture of follicles
3) through vessels (haematogenous)
4) through support structures - extension from muscles
Hyperkeratosis what diseases are typically associated with
1) Congenital ichthyosis*
2) Vitamin A deficiency
3) Zinc deficiency (Zinc-responsive dermatosis)
3) Seborrhea (primary and secondary)
4) Sarcoptic mange*
5) Superficial necrolytic dermatitis
Possible causes of acanthosis and is it reversible
internal factors (e.g. metabolic), or external injury (self trauma)is reversible
Actinic keratosis what is it, causes and macroscopical and histological changes
solar induced hyperplastic lesion
- skin which becomes erythematous with comedones and crusts, and palpably thickened
- It may progress to squamous cell carcinoma.
- Histologically there is hyperkeratosis and parakeratosis, epidermal hyperplasia
what are the typical areas where callus occurs
generally forms over a pressure point
- elbow, hock, sternum are most commonly affected
List 3 general causes of skin necrosis
1) Physical injury(chemical, thermal burns, radiation)*
2) Chemical injury (irritant contact dermatitis, toxic epidermal necrosis)
3) Injury as a result of vasculitis, ichemia and infarction (vasculitis, thromboembolism).
Consequences of thermal injuries to the skin
Erosion and ulceration usually follow and vesicles may develop due to dermal-epidermal separation. In full-thickness necrosis the damaged skin becomes firm and dry due to avascular necrosis and eventually sloughs. Secondary bacterial infections are common and can develop into life-threatening sepsis.
What are the 2 main histological features of skin burns
1) coagulation necrosis
2) dermal-epidermal separation
is spongiosis more likely to occur in acute or chronic injuries
acute as generally occurs with inflammation
What 3 diseases are characterised by cutaneous vesicles and what can result
1) Viral infections (poxvirus, vesicular diseases)
2) Pemphigus foliaceus or vulgaris, bullous pemphigoid
3) Thermal burns
Result of acantholysis or epidermal oedema
what is the difference between a vesicle and a pustule
Vesicle -> fluid-filled raised lesion <10mm
Pustule -> discrete, puss-filled, raised lesion
What is the typical mechanism for the development of acantholysis
initiated by damage to adhesion molecules, leading to splitting of the desmosomes
- typically occurs in immune-mediated diseases.
What are the gross features of photosensitisation and the pathogenic mechanism
Lesions on area without hair and non-pigmented
Sheep -> face, nose, eyelids lesions - dacial eczema
long wavelength UV absorbed by a complex photodynamic molecule and a biological substrate, which results in release of energy that produces reactive oxygen molecules, including free radicals -> chemical burns of the skin