Recurrent Neisseria infections are predisposed by –
**Core Concept**
Recurrent Neisseria infections, such as Neisseria gonorrhoeae (gonorrhea) and Neisseria meningitidis (meningitis), are often associated with deficiencies in the complement system, specifically the late components (C5-C9). This highlights the importance of the complement system in protecting against these infections.
**Why the Correct Answer is Right**
The complement system plays a crucial role in eliminating pathogens by promoting phagocytosis, inducing lysis, and enhancing inflammation. In the case of Neisseria infections, the late components of the complement system (C5-C9) form the membrane attack complex (MAC), which creates pores in the bacterial cell membrane, leading to cell lysis and death. Individuals with deficiencies in these late components are more susceptible to recurrent Neisseria infections.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the predisposition of recurrent Neisseria infections.
**Option B:** While IgA deficiency can increase susceptibility to infections, it is not specifically associated with recurrent Neisseria infections.
**Option C:** C3 deficiency is a more general immunodeficiency that affects the complement system, but it is not the most directly related to recurrent Neisseria infections.
**Clinical Pearl / High-Yield Fact**
A deficiency in the late components of the complement system (C5-C9) can increase the risk of recurrent Neisseria infections, such as meningitis and gonorrhea.
**Correct Answer: D. Complement component deficiency.**