What condition is most likely due to an immune-mediated mechanism involving lymphocytic infiltration?

The condition most consistent with an immune-mediated mechanism involving lymphocytic infiltration is Guillain-Barré syndrome. This syndrome is characterized by the body's immune system mistakenly attacking the peripheral nerves, leading to weakness and potentially paralysis. The immune response often follows a viral infection, where lymphocytes, a type of white blood cell central to the immune response, infiltrate the nerve tissues. This infiltration leads to demyelination, impairing the conduction of nerve impulses and resulting in the clinical manifestations of Guillain-Barré syndrome.

While encephalitis and meningitis can also involve immune-mediated processes and lymphocytic infiltration, they primarily affect the central nervous system and are often associated with viral infections. Conversely, a stroke typically occurs due to vascular events, such as blockage or rupture of blood vessels, rather than a direct immune-mediated process. Thus, Guillain-Barré syndrome is the most directly linked to an immune-mediated response characterized by lymphocytic infiltration.