Question
Giardia lamblia infection is common in:
| A. |
Selective IgM deficiency
|
| B. |
Selective IgA deficiency
|
| C. |
Common variable hypogammaglobulinemia
|
| D. |
Severe combined immunodeficiency
|
Show Answer
|
Correct Answer » B
Explanation
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|
- IgA is the principal immunoglobulin responsible for mucosal immunity.
- Giardia lamblia infects the gastrointestinal mucosa.
- Patients with selective IgA deficiency have impaired mucosal defense, making them particularly susceptible to recurrent giardiasis.
Clinical Features of Selective IgA Deficiency
- Recurrent sinopulmonary infections
- Chronic diarrhea
- Giardiasis
- Increased risk of autoimmune diseases
Reasons to Rule Out Other Options
A. Selective IgM deficiency
- Rare immunodeficiency
- Not classically associated with Giardia infection
C. Common variable hypogammaglobulinemia
- Giardia infection can occur, but the classic association in exams is with selective IgA deficiency
D. Severe combined immunodeficiency
- Causes severe recurrent opportunistic infections early in life
- Giardia is not the characteristic association
