title: Aquaporin-4 astrocytopathy in Baló's disease.
abstract: Baló's concentric sclerosis (BCS) is considered to be a rare variant of multiple sclerosis and characterized by alternating rings of demyelinated and preserved myelin layers. The mechanism underlying BCS remains to be elucidated. Recently, occurrence of concentric rings of Baló was described in the brainstem of a patient with neuromyelitis optica (NMO). Because selective loss of aquaporin-4 (AQP4) and vasculocentric deposition of complement and immunoglobulins are characteristic in NMO, we aimed to assess AQP4 expression in the concentric demyelinating lesions of BCS patients. We evaluated AQP4 expression relative to expression of another astrocytic marker (glial fibrillary acidic protein), the extent of demyelination, lesion staging and perivascular deposition of complement and immunoglobulin in four cases with BCS, and 30 individuals with other neurological diseases. All cases with BCS demonstrated extensive AQP4 loss in both demyelinated and myelinated layers of all actively demyelinating lesions, with perivascular lymphocytic cuffing of T cells, but no deposition of immunoglobulins or complement around vessels. These findings suggest that AQP4 loss occurs in heterogeneous demyelinating conditions, namely NMO and BCS. Furthermore, acute BCS lesions are characterized by extensive AQP4 loss without vasculocentric deposition of complement or immunoglobulin.
authors.affiliation: Department of Neuropathology, Kyushu University, Higashi-ku, Fukuoka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Satoshi O
authors.initials: SO
authors.lastname: Suzuki
authors.forename: Toru
authors.initials: T
authors.lastname: Iwaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tabira
authors.forename: Artemio T
authors.initials: AT
authors.lastname: Ordinario
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kira
mesh_terms: D000328:Adult; D051401:Aquaporin 4 / Q000378:metabolism*; D001253:Astrocytes / Q000378:metabolism* / Q000473:pathology*; D003165:Complement System Proteins / Q000378:metabolism; D003711:Demyelinating Diseases / Q000473:pathology; D002549:Diffuse Cerebral Sclerosis of Schilder / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000473:pathology; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000378:metabolism / Q000473:pathology; D055815:Young Adult
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D005904:Glial Fibrillary Acidic Protein; D007136:Immunoglobulins; D003165:Complement System Proteins