p-Tau181 -Alzheimer's Disease

We are pleased to offer analyses of pTau-181 in EDTA plasma on the SIMOA HD-X platform. Increased levels of pTau-181 can be detected in the early stage of Alzheimer´s Disease and can be of value in differentiating it from other neurodegenerative diseases.

Sez6L2 antibodies -Cerebellar ataxia

We have added a new marker to the Neurology test request form for Seizure-related 6 homolog-like 2 antibodies.

Plexin D1 antibodies -Small Fiber Neuropathy

Plexin D1 antibodies test are included in the Small Fiber Neuropathy panel and can also be ordered as an individual test.

p-tau181 in blood as a biomarker across the clinical continuum of Alzheimer's Disease

Karikari TK et al., Blood phosphorylated tau 181 as a biomarker for Alzheimer's disease: a diagnostic performance and prediction modelling study using data from four prospective cohorts. Lancet Neurol. 2020 May;19(5):422-433. PMID: 32333900

The use of an ultrasensitive blood immunoassay for p-tau181 was validated in four cohorts (1131 patients); the discovery cohort included patients with Alzheimer’s disease and age-matched controls. Two additional validation cohorts (TRIAD and BioFINDER-2) included cognitively unimpaired older adults, participants with mild cognitive impairment, Alzheimer’s disease, and frontotemporal dementia.

A primary care cohort comprised control participants and referred patients from primary care in Canada. In all cohorts, plasma p-tau181 showed gradual increases along the Alzheimer’s continuum, gradually increasing from low levels in amyloid β-negative individuals to higher concentrations in amyloid β-positive cognitively unimpaired older adults and reaching the highest concentrations in amyloid β-positive MCI and Alzheimer’s disease groups. 

Seizure-related 6 homolog-like 2 antibody-associated ataxia is an extremely rare disease. This case study shows a patient experiencing cerebellar ataxia. Whole-body CT and PET-CT scans revealed no pathology. SEZ6L2 antineuronal antibodies were found in CSF and serum. Over nine months of intense sequential immunotherapy, the patient markedly improved.

Small Fiber Neuropathy (SFN) often overlaps with other muscle/pain syndromes and can be found in fibromyalgia, associated with muscle cramps and complex regional pain syndrome. SFN has been reported in up to 40% of patients with fibromyalgia. Diabetes, sarcoidosis, hepatitis C, autoimmunity, Sjögren's syndrome, vitamin deficiency, toxic exposures, amyloidosis, paraneoplastic syndromes, and some rare genetic disorders have been reported as causes of SFN.

However, up to 50% of SFN cases remain unclear. This review article discusses that novel autoantibodies in cryptogenic SFN have recently been reported, and their discovery opened for improved diagnostics and the development of better symptomatic treatment.

These biomarkers included autoantibodies against TS-HDS, FGFR3, Plexin D1, PCA-2, CRMP-5, and CASPR2. Immune-mediate SFN has been shown to respond to IVIg treatment, and patients reported pain reductions.