Quantitative comparison of the IHC results between the gray and the white matter.

<p>(A) Distribution of HHV-6 positive glial cells in the encephalopathy group. (B) Distribution of S100 positive glial cells in the encephalopathy group. (C) Distribution of CD68 positive activated microglial cells/macrophages in the encephalopathy group and both control groups.</p

IHC.

<p>(A) Immunoreactivity observed in the olfactory tract of HHV-6 positive subjects: HHV-6 immunopositivity in the astrocytes (white arrow) and oligodendrocytes (black arrow), × 250. Confocal microscopy, representative image of HHV-6, insert, × 1000. (B) S100 immunopositivity in the cells of the olfactory bulb: positive neurons (white arrows), negative neurons (arrowheads), astrocytes (black arrows), × 200. (C) S100 and GFAP immunopositivity in the astrocytes (white arrows) and S100 positive oligodendrocytes (black arrows) of the olfactory tract, × 250; insert, × 200. (D) CD68 immunopositivity in the activated microglial cells/macrophages close to the neurons (black arrows) and oligodendrocytes (white arrow) of the olfactory bulb, × 200. (E) CD68 immunopositivity in the activated microglial cells/macrophages (black arrows) and MBP expression (white arrows) of the olfactory tract, × 250; insert, × 100.</p

TEM.

<p><b>Ultrastructural changes observed in the olfactory pathways of HHV-6 positive subjects.</b> (A) A fragment of neuron revealing irregularly dilated perinuclear space (white arrow), remarkable decrease of rough endoplasmic reticulum, polyribosomes (black arrows), mitochondria and vacuoles (arrowhead). (B) A fragment of astrocyte nucleus, an electron-lucent perinuclear cytoplasm (white arrow) with scanty intermediate filaments (black arrow). (C) Two oligodendrocytes with characteristically structured nuclear chromatin, dilated perinuclear space (white arrow) surrounded by a narrow rim of cytoplasm containing some swollen mitochondria (black arrows), cisternae of rough endoplasmic reticulum, and ribosomes. Myelin layer surrounding axons is thin; profiles of the paranodal loops are greatly varying. (D) Some myelinated axons and dendritic processes. Myelin layer of axons shows irregularity and ballooning of paranodal loops (black arrows).</p

Quantitative comparison of the IHC results between PCR⁺ and PCR^- cases.

<p>(A) Distribution of HHV-6 positive astrocytes and oligodendrocytes in the white matter of the encephalopathy group. (B) Distribution of HHV-6 positive oligodendrocytes in the white matter of the encephalopathy group compared to controls.</p

Cellular localization of S100 antigen in the olfactory pathways.

<p>Cellular localization of S100 antigen in the olfactory pathways.</p

Prevalence of the CD68 positive activated microglial cells/macrophages.

<p>Prevalence of the CD68 positive activated microglial cells/macrophages.</p