Although the infiltrated fMLP in this condition might not be as high as it is in the blood, or even under detectable levels, it could still be a potential threat to DA neurons because fMLP is toxic to DA neurons at concentration as low as 10−13 M. In addition, in a number of acute cerebral pathologies, including stroke, trauma, and meningitis, the blood–brain barrier permeability increases, allowing plasma proteins to enter the brain parenchyma. This evidence concerns the gene FPR1 and infectious meningitis.