Anti-Neuronal Antibodies - Diagnostic Tests

Screening for the presence of anti-neuronal antibodies is used in the following cases:

In the serological screening of patients with undetermined etiology of undiagnosed neurological disorder, especially in those patients with known cancer risk factors
In the focused search for potential cancers
Investigating neurological symptoms that occur during or after anticancer treatment that cannot be explained by the presence of possible metastases
In the differentiation of autoimmune neuropathies from the neurotoxic effects of anticancer chemotherapy
Monitoring of the immunological status of seropositive to anti-neuronal antibodies cancer patients, during anti-cancer therapy
In the detection of early signs of cancer recurrence in previously seronegative anti-neuronal antibody patients

Paraneoplastic Neurological Syndromes (PNSs) are rare syndromes caused by or associated with an underlying neoplasm. Paraneoplastic neurological syndromes do not occur as a result of the direct effect of the tumor on nerve tissue cells, but most are thought to be caused by the body's immune response to various onconeural antigens. These are antigens that are found in both neoplastic cells and normal cells of the nerve tissue and are recognized as foreign, thereby causing the production of autoantibodies (anti-neural antibodies) that attack both tumors and parts of the nervous system.

This "attack" of autoantibodies results in progressive neurological damage. Paraneoplastic neurological syndromes can affect many parts of the nervous system, and unlike most progressive neurodegenerative disorders, they usually have a rapid onset of symptoms. Patients may develop severe neurological disorder within a few hours such as for example, aesthetic neuropathy, idiopathic cerebrovascular dysfunction, or complaints of vision disorders (scotoma). In addition, many antibodies are usually associated with specific tumors. Thus, the presence of a particular autoantibody may also indicate the potential underlying tumor.

Detection of antibodies against onconeural antigens indicates the diagnosis of paraneoplastic syndrome and helps to focus research on the underlying tumor in specific organs.

The following table summarizes the anti-neural antibodies, the associated paraneoplastic neurological syndromes, and the most common underlying neoplasms.