Anti-Neuronal Antibody Testing
Anti-neuronal antibodies are present in the serum of patients with paraneoplastic disorders affecting the nervous system. These disorders have a very wide range of clinical presentations and often enter the differential diagnosis of complex neurological problems. Sensitivity and specificity of the tests available are difficult to state and vary according to clinical circumstances. Negative results do not preclude the possibility of an underlying paraneoplastic disorders. Strongly positive results in appropriate clinical circumstances should lead to a thorough search for an appropriate underlying neoplasm, although this search may ultimately be negative. In many human sera from individuals unaffected by paraneoplastic syndromes, low levels of antibody to paraneoplastic antigens may be detected using the sensitive assays performed; these results must be carefully considered along with the clinical findings in individual patients in order to assess their significance. The laboratory reports the results of the assays without reference to the patient demographics or clinical circumstances. Individual cases in which uncertainty in interpretation exists should be discussed with the laboratory director.
Paraneoplastic antigen-antibody pairs include anti-Yo (PCCA), anti-Hu (ANNA-1) and anti-Ri (ANNA-2) antibodies. They are screened in the first instance by immunofluorescent staining of sections from primate cerebellum.
Primate cerebellum can be used to detect the following antibodies:- GAD, PCA (Yo), ANNA1 (Hu), ANNA2 (Ri), Ma2Ta, Amphiphysin, CV2/CRMP5, SOX1, and Tr.
Positive or borderline samples are then screened for anti-Hu, -Yo, -Ri, -CV2, -Ma2/Ta, Titin, Recoverin, SOX1 and Amphiphysin activity by Immuno blot analysis using recombinant antigen kits. The recombinant antigen kits are highly sensitive and thus frequently detect low levels of antibody that are unlikely to be of clinical significance
(currently the Euroimmun Neuronal Antigens Profile PLUS RST Kit).
1ml of serum is required for these investigations.
The assay is conducted once a week and results reported that day.
Please use this link to view a table describing the most widely recognised associations between antibody, tumour type and clinical presentation: