While Relatively Rare, Individuals with a Homozygous Deficiency in Complement

question 8

Multiple Choice

While relatively rare, individuals with a homozygous deficiency in complement C1 activity have been identified, and >90% of them developed a lupus-like illness at a very young age. These individuals had significant kidney damage and damage to blood vessels in the central nervous system, both of which were associated with severe inflammation. A reasonable hypothesis to explain the development of the lupus-like disease in these patients is:

• A) Immune complex-mediated activation of the classical complement pathway
• B) Trapping of immune complexes in small blood vessels that block blood flow, leading to necrosis
• C) A non-immune function of C1 that is unrelated to the complement pathway
• D) A failure of immune complexes lacking complement deposition on them to bind to phagocyte Fc receptors
• E) A role for the complement pathway in clearing apoptotic cells from the circulation

---

Definitions:

Discrimination Training

A process in learning where an individual is trained to respond differently to distinct stimuli based on their attributes or consequences.

Generalization

Responding in the same manner to similar stimuli.

Conditioned Stimulus

A previously neutral stimulus that, after becoming associated with the unconditioned stimulus, eventually comes to trigger a conditioned response.

Parietal Lobe

A region of the brain associated with processing sensory information and spatial orientation.