H. Tomimoto et al., T-CELL INFILTRATION AND EXPRESSION OF MHC CLASS-II ANTIGEN BY MACROPHAGES AND MICROGLIA IN A HETEROGENEOUS GROUP IN LEUKOENCEPHALOPATHY, The American journal of pathology, 143(2), 1993, pp. 579-586
We report here on T-cell infiltration and diffuse expression of the ma
jor histocompatibility complex (MHC) class II antigen in a heterogeneo
us group of macrophages and microglia in leukoencephalopathy (LE). Mic
roglia reacting positively for HLA-DR were five times more numerous in
LE than those in non-LE cases and were distributed densely in the deg
enerated white matter but sparsely in the subcortical arcuate fibers.
CD4- and CD8-positive lymphocytes were 9 and 15 times more plentiful,
respectively, in LE cases; they aggregated in the expanded Virchow-Rob
in spaces and frequently infiltrated the neural parenchyma. An intimat
e association of T cells with macrophages, and the expression of leuko
cyte function-associated antigen-1 (LFA-1) and intercellular adhesion
molecule-1 (ICAM-1), accessory molecules in antigen presentation, were
observed in each cell in the region of macrophage clusters. These res
ults indicate that expression of MHC antigen is accompanied by cell ad
hesion molecules and by infiltration of T cells in a heterogeneous gro
up in leukoencephalopathy and suggests their immunocompetence, althoug
h it may be secondary to destruction of myelin.