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Flashcards in HS III Deck (26):
1

What type of reaction is a type III hypersensitivity reaction?

Immune complex deposition, targeting soluble antigens

2

How long does a type III hypersensitivity reaction take to develop?

3-8 hours

3

Which immunoglobulin is involved in type III hypersensitivity reactions and how does it cause a reaction?

IgG/IgM antibodies
React with soluble antigens to form immune complexes that are deposited in tissue and release toxins that damage the tissue

4

What factors affect immune complex pathogenesis?

Size of immune complex (big/small easily cleared)
Haemodynamic factors, clearance
Host response, low affinity antibodies less likely to form immune complexes
Complement deficiency, clearance

5

Describe the immune mechanism of type III hypersensitivity reactions

IgG/IgM antibodies bind with soluble antigens to form medium sized immune complexes that are deposited in tissue
Complement is activated
Neutrophil chemotaxis
Neutrophil binds to tissue and releases toxins

6

What antibodies are tested for in rheumatoid arthritis?

Autoantibody to rheumatoid factor (IgG)
Anti-cyclic citrullinated peptide (Anti-CCP)
Anti-citrullinated protein antibody (ACPA)

7

Describe the pathophysiology of rheumatoid arthritis

Chemoattractants in joints recruit B and T lymphocytes
Lymphocytes interact and drive overproduction of tumour necrosis factor, which causes synovitis and joint destruction
TNF also stimulates overproduction of IL 6 and other cytokines, recruiting more inflammatory cells

8

Describe how the lungs can be affected by rheumatoid arthritis

Nodules
Pleural effusion
Interstitial lung disease

9

Name non-articular manifestations of rheumatoid arthritis

Pericarditis
Nodules
Pleural effusion
Interstitial lung disease
Ankle oedema

10

Describe the articular manifestations of rheumatoid arthritis

Progressive, symmetrical, peripheral, polyarthritis with persistent synovitis and systemic inflammation

11

Describe the typical presentation of rheumatoid arthritis

30-50 years old
More likely female
Smoking risk factor
Chronic, symmetrical joint pain in the small joints
Morning stiffness lasting longer than 30 mins
Inflammed joints, hot and tender
Rheumatoid nodules

12

Which specific joints are typically affected?

Proximal interphalangeal joints and metacarpophalangeal

13

How is rheumatoid arthritis treated?

Corticosteroid: Prednisolone
+DMARD: Methotrexate/hydroxychloroquine

14

Describe the pathophysiology of glomerulonephritis

Infection with Hep B or bacterial endocarditis, IgG immune complex deposition in GBM, kidney damage

15

Describe typical X ray findings for rheumatoid arthritis

Narrowing of joint space
Osteoperosis localised to metacarpopharangeal joints
Small erosions at proximal phalanges
Soft tissue swelling involving all fingers

16

Name a monoclonal antibody used to treat rheumatoid arthritis

Tumour necrosis factor antibody

17

Describe how monoclonal antibodies can work in autoimmune disease

Bind to cell surface receptor to activate or inhibit signalling within cell
Bind to and be internalised by cancer cells to deliver toxins
Block inhibitory effects on T cells

18

Describe how monoclonal antibodies can be used to treat breast cancer

Trastuzumab
Inhibits HER-2 signalling (oncogene)

19

Describe how monoclonal antibodies can be used to treat lymphoma

Rituximab
CD 20 is expressed on all B cell surfaces, and rituximab is an antibody against CD20

20

Describe the pathophysiology of systemic lupus erythematosus

Self antigens form and the immune system fails to inactivate the B and T lymphocytes that recognise the self antigens - breakdown of tolerance
Autoantibodies form immune complexes that are deposited in tissues
Complement is activated
Influx of neutrophils, causing inflammation
Abnormal cytokine production

21

What features indicate systemic lupus erythematosus?

Antinuclear antibody present
Renal abnormalities
Arthritis
Photosensitive
Oral ulcers
Malar rash
Arthralga

22

How is systemic lupus erythematosus treated?

Corticosteriods: Prednisolone
DMARDs: Hydroxychloroquine/Azathioprine
Lifestyle modification and use of suncream

23

What antibodies are tested for in systemic lupus erythematosus?

Antinuclear antibodies (dsDNA)
Anti-Sm antibodies
Antiphospholipid antibodies

24

Describe the features of skin involvement in systemic lupus erythematosus

Butterfly/malar rash on face
Photosensitivity
Urticaria
Vasculitis
Purpura

25

Describe the findings of a full blood count in a patient with systemic lupus erythematosus

Anaemia
Low white cell count
Low platelet count

26

If haemolytic anaemia is present, which test confirms it as autoimmune?

Coombs test