In chronic granulomatous disease (CGD), granulocyte function is impaired. An association exists between this condition and a depression of which of the following antigens?

In chronic granulomatous disease (CGD), there is a defect in the phagocytic function of neutrophils due to a failure in the production of reactive oxygen species, which are essential for the killing of certain types of bacteria and fungi. CGD is particularly notable for its association with certain blood group antigens.

The Kell antigen system is affected in individuals with CGD. A depression of Kell antigens has been observed in the context of this disease mechanism. Specifically, studies have shown that individuals with CGD can present with lower expression of Kell antigens due to the disease's impact on the granulocyte population, leading to alterations in red blood cell antigen expression. This finding emphasizes the broader implications of immune system dysfunction, where not only does the innate immune response suffer but also the expression of specific blood group antigens may be altered.

The other options, while they are well-known blood group antigens, do not have the same established association with the immunological dysfunction seen in CGD. Therefore, Kell antigens are uniquely relevant in the context of chronic granulomatous disease, providing a clear link between the condition and specific antigen depression.