North Carolina Study Links Human Autoimmune Encephalitis Research to Canine Condition

Natasha Olby, MB, PhD, MRCVS, DACVIM, a study author and professor of veterinary neurology at North Carolina State, stated, “Being able to show that dogs suffer from a specific autoimmune encephalitis is really a paradigm shift.” While existing treatment options will remain the same, researchers aim to identify more antibody targets, possibly shifting diagnoses from 'unknown etiology' to ones based on identifiable neuronal cell surface targets.

Autoimmune encephalitis is an immune reaction affecting the brain and is difficult to treat in dogs. Currently, veterinarians often classify many non-infectious cases as “meningoencephalitis of unknown etiology.” Dr. Olby explained that when veterinarians diagnose encephalitis via MRI and spinal tap and rule out infections—as these make up only a small proportion of cases—they are left with this broad diagnosis and typically treat affected dogs with immunosuppression.

In human medicine, there is a clearer understanding of autoimmune encephalitis, largely due to the identification of antibodies against various neuronal surface proteins. The most common form, N-methyl-D-aspartate (NMDA) receptor encephalitis, has led to discoveries of multiple other antibody-associated forms of the condition.

Dr. Olby noted, “In reality, there are likely to be many different forms of autoimmune encephalitis in which the immune system is reacting to different targets within the brain.” Better classification of these conditions might improve prognosis predictions and treatment personalization.

For their study, Dr. Olby and her team applied a test designed to screen for antibodies against six specific neuronal surface targets found in humans to cerebrospinal fluid (CSF) from dogs diagnosed with encephalitis. The genetic similarity of these targets in humans and canines allows for the test’s effective implementation in dogs.

The team screened CSF samples from 32 dogs with both inflammatory and non-inflammatory neurological diseases. Among the 19 dogs diagnosed with inflammatory disease, three tested positive for antibodies against the NMDA receptor target and showed a favorable response to immunosuppressive therapy.

Dr. Olby remarked, “Being able to categorize the disease more accurately may give both dogs and humans more options for treatments in the future.” The researchers concluded that further evaluation of the prevalence and clinical significance of antibodies to neuronal cell surface antigens in both CSF and serum is necessary.