What is likely responsible for a secondary immune infection in a patient undergoing radiation therapy?

In the context of a patient undergoing radiation therapy, a secondary immune infection is often attributed to damage to the first-line barrier defenses. Radiation therapy can lead to changes in the skin and mucous membranes, which are critical components of the body’s initial defense against pathogens.

When these barriers are compromised, they are less effective at preventing microorganisms from entering the body. For example, radiation can cause skin breakdown, resulting in open wounds or ulcers, which increases the risk of infections by allowing bacteria to invade more easily. Additionally, damage to the mucosal membranes in areas such as the gastrointestinal tract can create vulnerabilities, leading to opportunistic infections.

The other options, while they may impact the immune system in different ways, do not directly pertain to the immediate risk factors for secondary infections as much as the impairment of first-line defenses does in the context of radiation therapy. Therefore, the primary concern for patients undergoing this type of treatment revolves around maintaining the integrity of the body's barriers to reduce the risk of infections.