Quantification of immunohistochemical findings of neurofibrillary tangles and senile plaques for a diagnosis of dementia in forensic autopsy cases.

Abstract

We report the quantification of immunohistochemical findings for a diagnosis of dementia in autopsy cases among older decedents. Autopsy cases were selected with the following requirements: >65yo; no head injuries, thermal injuries, or heat stroke; no intracranial lesions; and within 48h of death. Among cases that met all requirements, 10 had a clinical diagnosis of dementia were included in dementia group. Non-dementia group consisted of 38 cases without any record of dementia. To compare these groups, immunohistochemically, beta-amyloid, tau protein, gephyrin, and IL-33 were examined in five regions. Quantitative analysis was performed by collecting with image data analyzed using analysis software. Image data on tau-immunopositive neurofibrillary tangles (NFT) and beta-amyloid-positive senile plaques (SP) were photographed. Criteria for dementia were made by counting and measuring NFT and SP from image data using software. Differences in SP and NFT were effective for discriminating between the two groups. These criteria may reveal the presence and progression of dementia. Total of tau-positive NFT in Ammon's horn (AH) may be useful for diagnosing dementia. When the total is more than 41 in approximately 6mm(2) of AH, the possibility of dementia is considered. Total of beta-amyloid-positive SP in the parahippocampal gyrus (PHG) may be useful for diagnosing dementia. When the total in approximately 5mm(2) of PHG is more than 47, the possibility of dementia is considered. Immunohistochemical staining may be more useful for obtaining image data for quantification than conventional staining techniques, such as Bielschowsky-Hirano's silver staining.