IDENTIFICATION OF GLIAL-CELL PROLIFERATION IN EARLY MULTIPLE-SCLEROSIS LESIONS

Multiple sclerosis (MS) is a chronic inflammatory disease of the centr al nervous system which leads to destruction of myelin sheaths. The pa tterns of cell proliferation in the early course of the disease are la rgely unknown. The present study used immunohistochemical identificati on of proliferating glial cells in stereotactic brain biopsy material of eight patients with early chronic MS. Double-labelling with the pro liferation marker MIB-1 detected proliferating oligodendrocytes (MOG), astrocytes (GFAP) and microglia/macrophages (Ki-M1P). The majority of proliferating cells were macrophages/microglia when compared with oli godendrocytes (P > 0.005) or astrocytes (P > 0.0005); only a minor pro portion of microglia/macrophages, however, proliferated in situ. Astro cytic and oligodendroglial proliferation was sparse to absent and show ed significant variations between different patients. There were stati stically significant differences when comparing the amount of prolifer ation between lesions of different demyelinating activity: highest num bers of proliferating cells were found in early active lesions compare d with demyelinated and early remyelinated lesions (P > 0.05) or the p eriplaque white matter (P > 0.01). MOG-positive oligodendrocytes proli ferated occasionally in the early stages of lesion formation; this pro liferation occurred in four cases but was independent of the stage of the disease. Since MOG is expressed by mature oligodendrocytes, and no t: by immature precursors, this might suggest a potential role for the proliferation of mature surviving oligodendrocytes with subsequent re myelination.