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PA8.1-6,PA9.1-2 | Immunopathology & Amyloidosis — Practice Quiz
Practice
12 questions · Untimed · Unlimited attempts
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A 25-year-old man receives a bee sting and within minutes develops urticaria, bronchospasm, and hypotension. Which immunological mechanism is responsible?
A
IgG-mediated complement activation against erythrocytes
B
IgE crosslinking on mast cells causing degranulation
✓
C
Immune complex deposition in vessel walls activating C3
D
Sensitised CD8+ T-cell cytotoxicity against vascular endothelium
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A 30-year-old woman with autoimmune haemolytic anaemia (AIHA) has a positive direct Coombs test. Her red cells are coated with IgG and C3d. What hypersensitivity type and effector mechanism destroys her erythrocytes?
A
Type II — antibody-mediated complement lysis and opsonisation
✓
B
Type I — mast cell degranulation via IgE
C
Type III — soluble immune complex deposition activating neutrophils
D
Type IV — macrophage activation by IFN-γ-secreting Th1 cells
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A 28-year-old woman has joint pain, a butterfly facial rash, and proteinuria. Renal biopsy immunofluorescence shows granular 'full-house' deposits (IgG, IgM, IgA, C3, C1q) along glomerular capillary walls. Which hypersensitivity type best explains her nephritis?
A
Type I — IgE-mediated mast cell activation
B
Type II — antibody directed against glomerular basement membrane
C
Type III — immune complex deposition activating complement
✓
D
Type IV — CD4+ Th17 cell–driven neutrophilic inflammation
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A 42-year-old farmer presents with a pruritic, erythematous, vesicular rash on both hands that appeared 48 hours after handling pesticide. Patch testing confirms contact allergy to the chemical. Which cells are central to the effector phase of this reaction?
A
Mast cells sensitised with IgE
B
Eosinophils recruited by IL-5
C
Sensitised CD4+ Th1 cells and activated macrophages
D
Sensitised CD4+ Th1 cells releasing IFN-γ and cytotoxic CD8+ T cells
✓
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A patient with pulmonary tuberculosis undergoes a tuberculin (Mantoux) skin test. A 15 mm induration appears at 72 hours. Which mechanism explains this reaction?
A
IgE-mediated degranulation of dermal mast cells
B
IgM and IgG complement-mediated lysis of skin cells
C
Immune complex deposition activating the classical complement pathway
D
Memory T-cell activation releasing IFN-γ and recruiting monocytes/macrophages
✓
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A 35-year-old man is scheduled for a kidney transplant. His serum is found to contain preformed anti-donor HLA antibodies from a previous blood transfusion. Within minutes of reperfusion, the graft turns mottled and necrotic. What type of rejection has occurred?
A
Acute cellular rejection — host T-cell infiltration of tubules and vessels
B
Hyperacute rejection — preformed antibody + complement → immediate vascular thrombosis
✓
C
Chronic rejection — intimal fibrosis and obliterative vasculopathy over months
D
Graft-versus-host disease — donor T cells attacking host tissues
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A bone marrow transplant recipient (for acute leukaemia) develops diarrhoea, jaundice, and a maculopapular skin rash 3 weeks post-transplant. Skin biopsy shows lymphocytic infiltration of the basal layer. What is the most likely diagnosis?
A
Acute graft-versus-host disease (aGVHD)
✓
B
Acute cellular rejection of the marrow graft by residual host T cells
C
Hyperacute rejection from preformed antibodies to donor HLA
D
Chronic GVHD presenting as a scleroderma-like skin reaction
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A 22-year-old woman has recurrent fevers, a butterfly facial rash, and joint swelling. ANA is positive (1:640, homogeneous), anti-dsDNA titres are elevated, and serum C3/C4 are low. Which pathological finding in the kidney is most characteristic of her disease?
A
Granular 'full-house' sub-endothelial deposits with 'wire-loop' capillaries on light microscopy
B
Linear IgG deposits along the GBM on immunofluorescence
C
Effacement of podocyte foot processes on electron microscopy, no IF deposits
D
Granular mesangial and sub-endothelial immune complex deposits ('full-house' IF pattern)
✓
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A 40-year-old man presents with constitutional symptoms, oral candidiasis, and lymphadenopathy. HIV ELISA is positive; Western blot confirms bands to gp120, gp41, and p24. His CD4 count is 320 cells/µL. Which statement about HIV pathogenesis is correct?
A
HIV gp120 binds CD4 as primary receptor and CCR5/CXCR4 as co-receptor to enter CD4+ T cells and macrophages
✓
B
HIV primarily infects CD8+ cytotoxic T cells, gradually depleting cell-mediated immunity
C
HIV integrates its DNA into host chromosomes via reverse transcriptase, which also transcribes viral RNA
D
Western blot is the preferred initial screening test; ELISA confirms reactive results
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A 38-year-old HIV-positive man (CD4 count 45 cells/µL, not on ART) develops painless violaceous plaques on the lower limbs and soft palate. Biopsy shows proliferating spindle cells with slit-like vascular spaces and extravasated red blood cells. What is the diagnosis and associated pathogen?
A
Primary CNS lymphoma — associated with Epstein-Barr virus (EBV)
B
Kaposi sarcoma — associated with Human Herpesvirus 8 (HHV-8)
✓
C
Burkitt lymphoma — associated with EBV and c-MYC translocation
D
Invasive cervical carcinoma — associated with HPV 16/18
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A 55-year-old man with untreated multiple myeloma presents with macroglossia and carpal tunnel syndrome. Rectal biopsy stained with Congo red shows apple-green birefringence under polarised light. The amyloid deposits are composed of which precursor protein?
A
Serum amyloid A (SAA) protein — AA amyloidosis from chronic inflammation
B
Transthyretin (TTR) — hereditary or senile cardiac amyloidosis
C
Immunoglobulin light-chain fragments (kappa or lambda) — AL amyloidosis from plasma cell dyscrasia
✓
D
Beta-2 microglobulin — dialysis-related amyloidosis
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A clinical immunologist explains antigen presentation to medical students. She states that cytotoxic CD8+ T cells are activated only when intracellular antigens (viral peptides, tumour antigens) are presented by a specific MHC molecule. Which molecule is correct, and on which cells is it constitutively expressed?
A
MHC class II — expressed on B cells, dendritic cells, and macrophages only
B
MHC class II — expressed on all nucleated cells during viral infection
C
MHC class I — expressed on virtually all nucleated cells in the body
✓
D
MHC class I — expressed selectively on professional antigen-presenting cells
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