Paraneoplastic neurological syndromes (PNS) are diseases of the central and peripheral nervous system that occur in direct relation to tumour development. However, these are not caused directly by the tumour, by its metastases or by any side-effects from therapy using cytostatic drugs or radiation treatment. PNS occur in approximately 15% of malignant diseases, particularly in lung tumours.
Depending on the type of tumour, tumour cells express antigens, e.g. amphiphysin, CV2/CRMP5, PNMA2 (Ma2/ Ta), Ri, Yo, Hu, ZIC4 or Tr (DNER) which can induce the formation of specific autoantibodies. These autoantibodies bind to the respective antigens localised in the nervous tissue and can thus cause neurological disorders.
In the literature two types of nomenclature are used for PNS-specific autoantibodies. One is based on the first two letters of the index patient's name (e.g. Hu for Hull, Yo for Young, Ma for Margret), the other on the initial letters of the immunohistochemical staining (ANNA = anti-nuclear neuronal antibodies). We use the nomenclature of Posner (anti-Hu, -Yo, -Ma etc.), since this is antigen-based and independent of the test procedure.
The European network for paraneoplastic neurological diseases (PNS Euronetwork) has published diagnostic criteria. These lead to two levels of diagnostic certitude, namely a definitive or a possible paraneoplastic syndrome. In serological diagnostics, autoantibodies in PNS should always be determined using two unrelated methods. Various line blots (EUROLINE) are available in addition to indirect immunofluorescence tests with special BIOCHIP Mosaics for neurology. Thus, test results can be compared and, if necessary, confirmed. Results should only be used for diagnosis when both test results are congruent in qualitative determination and are in line with the clinical symptoms.