What condition results from complement deficiencies?

• A. Elevated immunity
• B. Increased susceptibility to infections
• C. Decreased inflammatory responses
• D. Enhanced antibody production

Answer: (B)

Complement deficiencies lead to a significant impact on the immune system's ability to fight infections. The complement system is a crucial part of the innate immune response that enhances the ability of antibodies and phagocytic cells to clear pathogens, while also promoting inflammation. When there is a deficiency in complement proteins, the immune system struggles to effectively identify and eliminate pathogens, which results in increased susceptibility to infections. This makes individuals with complement deficiencies more vulnerable to a variety of infections, particularly bacterial infections.

The other choices do not accurately reflect the consequences of complement deficiencies. Elevated immunity would imply a stronger immune response, which is not the case here. Decreased inflammatory responses may occur, but this is not the primary consequence and could lead to other issues rather than being a direct result of complement deficiencies. Enhanced antibody production is also not a result of complement deficiencies; rather, complementary systems work alongside antibodies and enhance their effect but do not directly increase their production.