Which condition may result from a deficiency in the C5 complement component?

A deficiency in the C5 complement component leads to an increased susceptibility to pyogenic infections, which are infections caused by bacteria that produce pus, commonly encapsulated organisms like Streptococcus pneumoniae and Neisseria meningitidis. The complement system plays a crucial role in the immune response, especially in opsonization, which enhances phagocytosis of bacteria. The C5 component is central to the formation of the membrane attack complex (MAC), which is important for lysing the cell membranes of certain pathogens. Without sufficient C5, the body is less able to effectively clear these types of infections, thereby increasing the risk of recurrent bacterial infections that are particularly difficult to manage.

While the other options present various immune-related issues, they do not specifically correlate with the deficiency of C5. Autoimmune diseases may be linked to other components of the complement system, and while T-cell function can be affected by various immune deficiencies, it is not directly tied to C5. Furthermore, the immune response to viral infections is generally more dependent on different pathways of the immune system, such as the role of interferons and other aspects of the adaptive immunity, rather than specifically on C5.