BSG and neonatal hemochromatosis: Because basigin (BSG) may induce activity of matrix metalloproteinases and thereby BBB breakdown, we investigated BSG expression in CAA brain tissue with immunohistochemistry and as cerebrospinal fluid biomarker for BBB dysfunction in patients with CAA.<h4>Methods</h4>Using immunohistochemistry, we quantified BSG expression within the cortical microvasculature of the temporal lobe of 50 CAA patients (16 with intracerebral haemorrhage [CAA-ICH] and 34 without intracerebral haemorrhage [CAA-NH]) and 35 controls.