We are pleased to inform you that Neuroimmunology at Queen Elizabeth University Hospital Glasgow is now able to offer testing for anti-GAD65 antibodies associated with Stiff Person Syndrome. As the test has just been introduced we have applied to have it added as an extension to scope to our current UKAS accreditation.
Frequency and Turnaround Time
Requests for anti-GAD antibody levels will be processed approximately every 2 weeks. An initial screen will be performed which will detect titres of up to 1:2000. For samples with higher titres in patients with neurological symptoms a further titration will be performed up to 1:50,000, on the next scheduled run of the assay. Results will be available approximately 2 weeks from receipt. In the event that further titration is required, this may delay results for a further 2 weeks. Separate reports will be issued for each titration.
For internal requests, please note that the higher titration will only be automatically carried out on samples testing >2000 on the initial screen if the initial request on Trakcare was for "GAD65 - Stiff person serology" and not on Trakcare requests for "Autoimmune diabetic serology".
The laboratory participates in the UK NEQAS scheme.
1 ml serum
We are pleased to inform you that Neuroimmunology at Queen Elizabeth University Hospital Glasgow is now able to offer testing for Anti- glutamate receptor (Type NMDA) antibodies and Anti- voltage gated potassium channel associated proteins (LGI1 and CASPR2).
•Anti- glutamate receptor (Type NMDA) antibodies
Anti-NMDA receptor encephalitis manifests along a spectrum of psychosis, altered behaviour, movement disorder, seizures, autonomic dysfunction and decreased consciousness. In younger patients, particularly female, it is associated with an underlying teratoma. Early identification and treatment with immunotherapy leads to better outcomes (Pubmed ID 23290630). It is less common in older patients (over 45 years old) and they display a less severe phenotype and have poorer outcomes (Pubmed ID23946310).
Antibodies against the NR1 subunit of the NMDA receptor are identified in our laboratory via indirect immunofluorescence of cell lines transfected with cDNA coding this protein. This test has very high positive and negative predictive values. Testing is carried out on serum or CSF. CSF is preferred for testing since there are fewer false positives or false negatives compared with serum.
•Anti- voltage gated potassium channel associated proteins (LGI1 and CASPR2)
Antibodies against the VGKC associated proteins LGI1 and Caspr2 are associated with a number of neurological syndromes.
Anti-LGI1 antibody encephalitis usually manifests in a number of ways. It can cause faciobrachial dystonic seizures (FBDS), other focal seizures - often with prominent autonomic features - a more pronounced limbic encephalitis with amnesia, cognitive decline and seizures, or it can cause a rapidly progressive encephalopathy (Pubmed ID 27590293).
Anti-Caspr2 antibody mediated syndromes include peripheral nerve hyperexcitability, Morvan syndrome and a more protracted, subacute limbic encephalitis with encephalopathy, seizures, cerebellar dysfunction, autonomic disturbance, neuropathic pain, insomnia and weight loss (Pubmed ID 27371488).
Antibodies against Caspr2 or LGI1 are identified in our laboratory via indirect immunofluroscence of cell lines transfected with cDNA coding the protein of interest. This is a very specific and sensitive test for antibodies against these antigens and an alternative to the anti-voltage-gated potassium channel complex antibody (VGKCC) radioimmunoassay.
Frequency and turnaround time
Both assays are carried out weekly, currently on a Monday. Results will be available within 1 week of receipt. In the event that repeat testing is required, this may delay results for a further week.
The laboratory takes part in the Institute for Quality Assurance LÜbeck an EQA scheme run by Euroimmun.
1 ml serum or 1ml CSF (NMDA only)