Additional file 5: Figure S4. of Brainstem tau pathology in Alzheimer’s disease is characterized by increase of three repeat tau and independent of amyloid β

Predominance of RD3+ NFTs over RD4+ NFTs is shared between brainstem and hippocampus. To see whether the same trend of RD3 dominance for the neurofibrillary changes over RD4 is also demonstrated by the conventional DAB immunohistochemistry, we performed quantification of the RD3 and RD4 levels on representative adjacent pontine and hippocampal sections. After thresholding of the DAB labeling by RGB values, the counts and sizes of RD3 and RD4 were calculated on CellSens software (Olympus). RD3/RD4 ratio of total NFT counts and area on the pontine section were 6.00 and 4.49, respectively, indicating more intense deposition of RD3-positive neurofibrillary changes than RD4 (a, c, case 17). While the difference in the methods used make direct comparisons difficult, this observation of RD3 dominance agreed with our double-immunofluorolabeling of the same case using anti-4R tau antibody and RD3. RD3/RD4 ratio of total NFT counts and area on the hippocampal sections were 25.6 and 34.3, respectively. Thus, the dominance of 3R tau was also detected for the neurofibrillary changes in the hippocampal area of the same case (b, d, case 17). (TIFF 3761 kb)