Clinico-pathological correlation in adenylate kinase 5 autoimmune limbic encephalitis

• First reported pathology of adenylate kinase 5 (AK5)-autoimmune limbic encephalitis
• Immunohistochemistry confirms a predominantly cytotoxic T-cell process.
• No evidence of cancer found on autopsy
• AK5 autoimmune limbic encephalitis may not be paraneoplastic in nature.
• AK5 autoimmunity may herald a poorly-responsive or refractory course.

Autoantibodies associated with autoimmune limbic encephalitis (ALE) have been well-characterized, with intracellular neuronal antibodies being less responsive to immunotherapy than antibodies to cell surface antigens. Adenylate kinase 5 (AK5) is a nucleoside monophosphate kinase vital for neuronal-specific metabolism and is located intracellularly in the cytosol and expressed exclusively in the brain. Antibodies to AK5 had been previously identified but were not known to be associated with human disease prior to the report of two patients with AK5-related ALE (Tuzun et al., 2007). We present the complete clinical picture for one of these patients and the first reported neuropathology for AK5 ALE.