Which is a potential consequence of impaired immune function?

The selection of higher risk of autoimmune diseases as a potential consequence of impaired immune function highlights a critical aspect of immunology. Impaired immune function can lead not only to an increased susceptibility to infections but also to dysregulation of the immune system, which can manifest in autoimmune disorders.

In individuals with compromised immunity, the body's ability to distinguish between self and non-self can become impaired. This may result in the immune system mistakenly attacking the body’s own tissues, thereby triggering autoimmune diseases. Conditions such as lupus, rheumatoid arthritis, and multiple sclerosis are examples where the immune system's misfiring leads to tissue damage and inflammation.

In contrast, the other options emphasize outcomes that are either advantageous or not reflective of impaired immune function. For example, an increased ability to fight infections would be more associated with a robust immune response, not impaired function. Enhanced responses to vaccinations also indicate a well-functioning immune system capable of developing memory against pathogens. Lastly, stronger natural barriers to pathogens suggest a healthy immune system's capacity for protection, which is the opposite of what would be expected in the context of immune impairment. Thus, the elevated risk of autoimmune diseases is the most accurate reflection of the consequences that arise from a compromised immune system.