In cases of cell-mediated immune deficiency, which infection is most likely to occur?

• A. Candida
• B. Strep throat
• C. Herpes simplex
• D. Influenza

Answer: (A)

In cases of cell-mediated immune deficiency, the most likely infection to occur is due to opportunistic pathogens that thrive when the immune system is compromised, particularly the T-cell response. Candida, a type of yeast, is an opportunistic pathogen that typically causes infection in individuals with weakened cell-mediated immunity.

Cell-mediated immunity primarily involves T-cells, which are crucial for controlling fungal infections like those caused by Candida, as well as for responding to certain viral infections and intracellular bacteria. When this arm of the immune system is deficient, the body becomes less capable of controlling fungal proliferation, leading to an increased risk of infections, such as oral thrush or systemic Candida infections.

While the other options listed can also be associated with infections, they primarily involve different immune mechanisms. For example, streptococcal infections may activate humoral immunity without as significant a need for T-cell function, herpes simplex virus typically reactivates more readily in individuals with both humoral and cellular immunity issues, and influenza primarily evokes an antibody response via B-cells and does not specifically rely on cell-mediated immunity. Hence, Candida infections are particularly characteristic of cell-mediated immune deficiencies.