Immunodeficiency vs autoimmunity — Which of the following is an example of an immunodeficiency disorder?

Introduction:
Immune disorders can be broadly classified as excessive/misdirected (allergy, autoimmunity) or insufficient (immunodeficiency). This question checks your ability to distinguish examples of each category and identify a true immunodeficiency state.

Given Data / Assumptions:

• AIDS results from acquired immune deficiency due to HIV.
• Autoimmune diseases feature immune attack on self tissues.
• Hypersensitivity reactions may be antibody-mediated or T-cell-mediated but are not deficiencies.

Concept / Approach:
Match each option to its category: immunodeficiency (lack of function) vs autoimmunity/hypersensitivity (misdirected/exaggerated function). Select the one that reflects deficient immunity.

Step-by-Step Solution:

Verification / Alternative check:
Diagnostic criteria for AIDS rely on low CD4 counts and indicator infections, directly evidencing deficient immunity.

Why Other Options Are Wrong:

Common Pitfalls:
Labeling any immune-related disease as “immunodeficiency” without considering whether function is excessive/misdirected vs absent.

Final Answer:
AIDS.