doi:10.1016/j.expneurol.2006.06.012
Copyright © 2006 Elsevier Inc. All rights reserved.
Short Communication
Peculiar labeling of cultured hippocampal neurons by different sera harboring anti-glutamic acid decarboxylase autoantibodies (GAD-Ab)
Marika Vianelloa,
,
, Bruno Giomettoc, Stefano Vassanellia, Marta Canatoa, Corrado Betterleb and Carla Mucignata
aDepartment of Human Anatomy and Physiology, Section of Physiology, Via Marzolo 3, 35131 Padova, Italy
bDepartment of Internal Medicine, University of Padova, Italy
cOperative Unit of Neurology, Treviso Hospital, Italy
Received 16 April 2006;
revised 21 June 2006;
accepted 28 June 2006.
Available online 7 August 2006.
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Abstract
Immunological derangement is assumed to be present in a subgroup of patients affected by drug-resistant epilepsy with serum harboring anti-glutamic acid decarboxylase autoantibodies (GAD-Ab).
To further investigate the specific reactivity of GAD-Ab with target cells, we tested sera from drug-resistant epileptics harboring GAD-Ab on cultured fetal rat hippocampal neurons. As a control, we tested sera from GAD-Ab-negative epileptics and GAD-Ab-positive patients affected by Stiff Person Syndrome (SPS), ataxia or diabetes.
A specific pattern of reactivity, varying according to disease, was detected on application of sera from GAD-Ab-positive patients with epilepsy, SPS and ataxia, but no specific labeling was found on application of sera from patients with GAD-Ab-negative epilepsy or from GAD-Ab-positive diabetic controls.
Keywords: Drug-resistant epilepsy; Stiff Person Syndrome; Ataxia; Neurological disorders; Diabetes; Hippocampal neurons in culture
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Fig. 1. (A) Indirect immunofluorescence (IIF) with serum from a GAD-Ab-positive epileptic patient on rat hippocampal neurons: intense perinuclear staining, with a faint reactivity of cytoplasm and processes and glial cells. No reactivity of neuronal nuclei and of glial cells (40×). (B) IIF with a serum from GAD-Ab-positive ataxic patient: dotted reactivity concentrated on the cytoplasm (white arrows), near neurite outgrowth; no reactivity on glial cells (open arrows) (40×). (C) IIF with serum from GAD-Ab-positive SPS patient: reactivity of some neurites and diffuse labeling of the cytoplasm, sparing glial cells (40×). (D) IIF with serum from GAD-Ab-negative drug-refractory epileptic: no reactivity on both neurons and glial cells (40×). (E) IIF with serum from GAD-Ab-positive diabetic: diffuse labeling of both neurons and glial cells (open arrows) (40×). (F) IIF showing the co-localization (yellow signal) of commercial polyclonal anti-GAD Ab (red signal, right insert) labeling GABAergic neurons and purified IgG from epileptic patient (green signal, left signal) (40×). White bar = 25 μm.
Table 1.
Reactivity on IHC, RIA, WB (both on whole mouse cerebellum homogenate and rGAD65) and hippocampal neurons in culture

M: man, F: female; ND: not done.