Abstracts

Rationale: We noted that α-B-crystallin (αBc), related to heat shock protein HSP-27, is often upregulated in neural cells of resected epileptic foci in children. It may serve as a marker of epileptic encephalopathy. These observations justified a prospective study in cerebral tissue from epileptic foci.Methods: Surgical brain resections from 24 children, 3 mos to 17 yrs, with intractable epilepsy, were prospectively examined immunocytochemically for αBc. Other neuronal, glial and inflammatory cell markers also were applied. Similar examination was performed postmortem in 20 normal fetuses of 9-41 wk gestation, 10 brains with major cerebral malformations, 6 fetal and postnatal infarcts and 2 children in status epilepticus before death.Results: αBc is not expressed at any stage of normal ontogenesis or in developmental malformations. In tissue of chronic epileptic foci at all ages it is upregulated in astrocytes (including satellite cells of cortex), oligodendrocytes and occasionally neurons of neocortex, hippocampus and heterotopic in white matter. Cytoplasmic expression may be weak or strong. Balloon cells are strongly reactive. It also is overexpressed in glial cells surrounding infarcts, especially gemistocytes, but does not specifically correlate with inflammation, microglial activation or gliosis.Conclusions: αBc is a tissue marker of epileptic encephalopathy in children, but does not indicate dysgenesis or arrested maturation. It is probably a reactive change induced by repetitive epileptic discharges or by chronic ischemia.