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Zorluk: KolayImmunologic and Inflammatory Processes

Match the following clinical presentations to their underlying primary immunopathologic mechanism.

  • A 22-year-old man develops acute wheezing, facial swelling, and urticaria shortly after eating peanuts.Type I hypersensitivity (IgE-mediated)
  • A 30-year-old woman presents with hemoptysis and hematuria; renal biopsy shows linear IgG deposits along the basement membrane.Type II hypersensitivity (Antibody-mediated cytotoxic)
  • A 45-year-old man develops fever, diffuse polyarthralgia, and a cutaneous rash 8 days after starting a new medication.Type III hypersensitivity (Immune complex-mediated)
  • A 25-year-old woman presents with a localized, pruritic, vesicular rash on her arms 48 hours after gardening.Type IV hypersensitivity (T-cell mediated delayed)

Cevap

The correct matches align the four classical types of hypersensitivity reactions with their prototypical clinical presentations: Type I (Anaphylaxis), Type II (Goodpasture syndrome), Type III (Serum sickness), and Type IV (Contact dermatitis).
Each clinical vignette provides pathognomonic clues for the four primary classes of hypersensitivity. Rapid onset allergy aligns with IgE-mediated (Type I); linear autoantibody deposition aligns with cytotoxic (Type II); systemic immune complex deposition aligns with Type III; and delayed, cell-mediated localized rash aligns with Type IV.

Adım Adım Çözüm

1
Analyze the first clinical presentation (acute reaction to peanuts) and identify the underlying rapid, IgE-mediated immune response.
The scenario is recognized as Anaphylaxis, which matches with Type I hypersensitivity.
Rapid onset of urticaria and wheezing upon allergen exposure is the hallmark of mast cell degranulation.
2
Examine the second presentation (hemoptysis, hematuria, and linear IgG tissue deposition) to determine the mechanism of tissue injury.
The findings represent Goodpasture syndrome, matching with Type II hypersensitivity.
Linear IgG deposition implies direct antibody binding to fixed intrinsic tissue antigens (anti-GBM antibodies).
3
Evaluate the third presentation (fever, rash, and joint pain delayed 8 days after medication exposure) to identify the systemic immune reaction.
The constellation of symptoms indicates Serum Sickness, which matches with Type III hypersensitivity.
Delayed onset of systemic symptoms following drug exposure is characteristic of circulating antigen-antibody complex formation and subsequent tissue deposition.
4
Assess the final presentation (localized vesicular rash appearing 48 hours after allergen exposure) to establish the immune pathway involved.
The scenario characterizes Contact Dermatitis, mapping directly to Type IV hypersensitivity.
A 48 to 72-hour delay in localized symptom onset points to a cell-mediated (T-cell) rather than an antibody-mediated response.

Anahtar Kavram

The four main classifications of hypersensitivity reactions (Gell and Coombs) have distinct temporal profiles, mediators, and clinical manifestations.
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Immunologic and Inflammatory Processes

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