Diagnostic Performance of a Commercial Indirect Immunofluorescence Assay for the Detection of Neuronal Antibodies in Auto-immune Encephalitis and Paraneoplastic Neurological Syndromes

Detection of autoantibodies targeting neuronal surface or intracellular antigens is a keystone for the diagnosis and the treatment of auto-immune encephalitis and paraneoplastic neurological syndromes. A strategy commonly used for their detection is to perform a screening with a tissue-based immunofluorescence assay or immunohistochemistry assay and a second line test to confirm and identify the autoantibody. Since several years, commercial kits are used by a growing number of laboratories to screen the presence of these autoantibodies. However, the diagnostic performance of these commercial kits is highly variable and several studies reported a high prevalence of false-positive and false-negative results with commercial immunodots and cell-based assays. It is therefore essential to explore commercial kits limitations in order to avoid false-positive and false-negative results that could lead to misdiagnosis and/or to delay the treatments.

To assess the diagnostic performance of commercial kits, the investigators performed a prospective study in which the investigators screened patients neuronal autoantibodies in cerebrospinal fluid and sera using commercial tissue-based indirect immunofluorescence assay and CBAs in comparison with an in-house tissue-based indirect immunofluorescence assay.