Fig. 2

Brain biopsy results of a patient with reversible leukoencephalopathy. a to j: Brain biopsy results of the patient with reversible leukoencephalopathy prior to atypical mycobacteria treatment shows (a) mild tissue rarefaction with vacuolation, very sparse perivascular inflammatory infiltrates, and (b) no evidence of demyelination. c–d Presence of relatively few glial fibrillary acidic protein (GFAP) positive astrocytes with reduced aquaporin-4 expression in the lesion compared to the surrounding area. Scale bar = 100 μm. High magnification (400x) on D shows aquaporin-4 on the membrane of reactive astrocytes. Scale bar = 10 μm. e Aquaporin-1 expression is also reduced in the lesion, but in less extensively than aquaporin-4. f–g Myelin sheath is preserved with no loss of myelin basic protein (MBP) and myelin associated glycoprotein (MAG). h No signs of neuronal or axonal damage. i–j Few lymphocytes (CD45+) and macrophages (CD68+) are found in the perivascular space, while immunoglobulin and complement C9neo deposition are absent (not shown). Scale bar = 50 μm. (Magnification a–d = 100x; e–j = 200x)