FIGURE 3.

Representative images of histochemical and immunohistochemical comparison of different lesion areas in a chronic active plaque. Control WM of male control subject of 66 years old. (a) Characteristic myelin pattern in WM area. (b) Consecutive section immunostained for Apo D. (c) Colocalization of myelin and Apo D immunohistochemistry in cytoplasm and processes of OLGs. Female subject of 52 years old with MS (d–o). Periplaque WM. (d) Characteristic myelin pattern in periplaque area. (e) Consecutive section immunostained for Apo D showing mainly positive OLGs (arrow), but also astrocytes (arrowhead) as it is shown in the insert. (f) Colocalization of myelin and Apo D immunohistochemistry in cytoplasm and processes of OLGs. Apo D containing granules were found surrounding myelin sheath. Active area. (g) Active demyelination can be observed in this area. (h) Intensity of the immunostaining for Apo D is weaker than in the periplaque WM. Apo D positive macrophagic cells (top insert) and less OLGs can be observed in this area (bottom insert). (i) Double stain for myelin and Apo D. The arrowhead points to the granular content of distal processes of OLGs around myelin sheath. Inactive area. (j) Myelin stain shows a completely demyelinated area. (k) This area is negative for Apo D with the exception of a few astrocytes with a weak staining (insert). (l) No myelin nor Apo D label can be found in inactive plaque area. Remyelination area in a sclerosis plaque. (m) A package of myelinated axons passing by a demyelinated area. (n) Consecutive section immunostained for Apo D. Positive OLGs can be observed in this area (arrow in the insert). (o) Myelinated axons stained with LFB also present granular Apo D immunostaining surrounding (arrowheads). Scale bars: (a,b,d,e,g,h,j,k,m,n), 30 μm (10×); (c,f,i,l,o), 10 μm; (Inserts), 10 μm (100×).