Immunopathology

Topics in this chapter

• Hypersensitivity Mechanisms
• Autoimmune Diseases
• Immunodeficiency Disorders
• Immune-Mediated Kidney Disease
• Immune-Mediated Vasculitis and Thrombosis
• Transplant Rejection

Practice questions

1. Question 1Q-9A8613

   A 32-year-old woman presents with malar rash, arthralgia, and generalized fatigue. Laboratory investigations reveal positive anti-nuclear antibodies (ANA) and anti-double-stranded DNA (anti-dsDNA) antibodies. Renal biopsy shows 'wire-loop' lesions of the glomerular capillaries by light microscopy. Which type of hypersensitivity reaction is primarily responsible for the glomerular injury in this condition?

   1. A.Type I hypersensitivity
   2. B.Type II hypersensitivity
   3. C.Type III hypersensitivity
   4. D.Type IV hypersensitivity
   See the answer and solution
2. Question 2Q-844462

   A 4-year-old boy suffers from recurrent sinopulmonary bacterial infections since 6 months of age. Laboratory workup reveals profound hypogammaglobulinemia, markedly reduced B cells in peripheral blood, but normal T-cell numbers and function. Tonsils are significantly hypoplastic. Genetic analysis is likely to reveal a mutation in which of the following genes?

   1. A.BTK (Bruton tyrosine kinase)
   2. B.AICDA (Activation-induced cytidine deaminase)
   3. C.CD40LG
   4. D.JAK3
   See the answer and solution
3. Question 3Q-CAFD5A

   A 25-year-old man undergoes an uneventful kidney transplantation from an HLA-matched sibling. Within minutes of releasing the vascular clamps, the kidney becomes cyanotic, mottled, and flaccid, and urine output ceases. Histological examination of the rejected graft would most likely demonstrate:

   1. A.Acute cellular rejection with dense interstitial lymphocytic infiltration
   2. B.Hyperacute rejection with thrombotic occlusion of glomerular capillaries and fibrinoid necrosis
   3. C.Chronic rejection with smooth muscle proliferation and arterial intimal thickening
   4. D.Graft-versus-host disease with lymphocytic apoptosis in crypts
   See the answer and solution
4. Question 4Q-76BB20

   A 10-month-old infant presents with recurrent viral, fungal, and protozoal infections, persistent thrush, and severe diaper dermatitis. Chest X-ray reveals the absence of a thymic shadow. Laboratory tests show very low T-cell counts and impaired T-cell proliferative responses, while B-cell numbers may be normal or increased (though non-functional). This condition is most frequently caused by an X-linked mutation in which gene?

   1. A.ADA
   2. B.IL2RG
   3. C.RAG1/RAG2
   4. D.ATM
   See the answer and solution
5. Question 5Q-B62751

   A 30-year-old woman presents with progressive fatigue, muscle weakness that worsens with repetitive activity, and double vision by the end of the day. Edrophonium test provides immediate, temporary relief of her symptoms. The underlying immunopathological mechanism involves autoantibodies directed against which specific target?

   1. A.Voltage-gated calcium channels at the presynaptic membrane
   2. B.Postsynaptic nicotinic acetylcholine receptors
   3. C.Acetylcholinesterase enzyme in the synaptic cleft
   4. D.Myelin basic protein of peripheral nerves
   See the answer and solution