In which type of acne lesion would you expect to find a significant invasion of white blood cells?

In a pustule, you would expect to find a significant invasion of white blood cells because this type of acne lesion is essentially an inflamed papule filled with pus, which is composed of dead white blood cells, bacteria, and debris. The presence of pus is indicative of the body’s immune response to an infection, and in the case of acne, this typically occurs when bacteria proliferate in clogged pores.

The accumulation of white blood cells in the pustule reflects the body’s attempt to fight off these bacteria. This inflammatory response is part of the body's defense mechanism, resulting in the visible signs of inflammation, such as redness and swelling around the lesion.

Other types of acne lesions, like papules, comedones, and nodules, do not exhibit the same level of white blood cell involvement as pustules. For example, papules are often red and raised but do not contain pus, while comedones (both open and closed) are non-inflamed and do not involve significant immune response. Nodules may have some inflammatory components but are more solid and deeper than pustules, so they don't necessarily show the same accumulation of white blood cells as seen in pustules.