Which condition results directly from a significant reduction in spleen function?

A significant reduction in spleen function directly increases the risk of infections. The spleen plays a critical role in the immune system by filtering the blood, removing old or damaged red blood cells, and playing a vital part in the body's response to infections. It contains white blood cells that help fight off pathogens, particularly encapsulated bacteria.

When the spleen is not functioning effectively, the body’s ability to respond to infections diminishes. This is especially true for certain types of bacteria that rely on the presence of a fully functional spleen to be effectively dealt with. Individuals with compromised spleen function are therefore at a higher risk for infections, particularly those caused by encapsulated organisms such as Streptococcus pneumoniae and Haemophilus influenzae.

The other options do not align with the physiological roles of the spleen. Increased ability to filter toxins or improved blood filtration is not a consequence of reduced spleen function; rather, the opposite occurs. Decreased blood pressure is also unrelated to spleen function, as blood pressure regulation involves multiple systems and mechanisms, none of which are directly impacted by the spleen’s role.