MAPT and amyloidosis: Lumbar punctures were performed for clinical reasons and CSF biomarkers were routinely available: we analyzed blood brain barrier permeability (CSF to serum albumin ratio, “CSAR”), intrathecal IgG synthesis, (CSF to serum IgG ratio), inflammation (neopterin), amyloid deposition (Aβ1–42), neuronal damage (T-tau, P-tau, 14.3.3) and astrocytosis (S-100 β).