Common forms of acute and peripheral neuropathy are now being recognized as autoimmune in etiology and many are responsive to treatment if diagnosed. Anti-ganglioside antibodies have been found in autoimmune neuropathies, especially in axonal variants of Guillain-Barré syndrome, acute motor axonal neuropathy (AMAN) and acute motor-sensory neuropathy (AMSAN), chronic inflammatory demyelinating polyneuropathies (CIDP) and Miller Fisher syndrome, Motor Neuron Disease (MND) and multifocal motor neuropathy (MMN). The Neuropathy panel is performed using the sensitive Immunoblot assay and tests for the following antibodies: GM1, GM2, GM3, GD1a, GD1b, GT1b, GQ1b. Ref: Plomp and Willison. (2009). J Physiol. PMID: 19564393.

Paraneoplastic Neurological Syndromes (PNS) are autoimmune mediated complications of cancer. These can present when cancer is small and curable and sometimes years before the appearance of malignancy, therefore, diagnosis allows the significant opportunity for early therapeutic intervention. PNS may present with cerebellar degeneration (subacute), limbic encephalitis, brainstem encephalitis, and sensory neuronopathy. In PNS, the tumor cells express antigens that normally only occur in neurons, inducing an auto-antibody response leading to neuronal injury. PNS develops in ~15% of malignant cancers, occurring most frequently in small-cell lung carcinoma, neuroblastoma, thymoma, and cancers of the ovary, breast, uterus, and testis. Onco-neuronal antibodies in PNS are directed against intracellular neuronal antigens: Amphiphysin, CV2, PNMA2/Ta, Ri/Anna2, Yo/Pca-1, Recoverin, Hu/Anna, SOX, Titin. A positive result for this panel has a high probability of a tumor. In concordance with clinical data, detection of anti-neuronal autoantibodies is considered sufficient for a definitive diagnosis of PNS. Ref: Höftberger et al. (2015). Curr Opin Oncol. PMID: 26335665.

SPS is a rare neurological disease, which can be paraneoplastic or non-paraneoplastic in origin. The disease manifests with severe progressive muscle stiffness, typically in the spine and lower extremities and may be confused with Parkinson’s Disease. Paraneoplastic cases are associated with antibodies against amphiphysin. Non-paraneoplastic cases are characterized by autoantibodies against glutamate acid decarboxylase (GAD), which are found in 60-90% of patients. However, anti-GAD antibodies are not specific markers for the stiff-person syndrome as they also occur in other neuronal diseases and, in particular, diabetes mellitus type I. Ref: Rakocevic et al. (2012). Muscle Nerve. PMID: 22499087.

Alzheimers Disease (AD) is the most common form of Dementia and affects 2% of population above 65 years of age. Majority of patients are left undiagnosed which is unfortunate as now there is treatment available to slow down the progression of dementia and improve cognition and quality of life. Clinical diagnosis is unreliable. The neuropathology of AD starts decades before the onset of clinical disease and is reflected in the concentrations of Beta- amyloid 1-42 and total Tau protein in the CSF. Beta amyloid alone and tau alone are sensitive but not specific for AD but when both assays are used together, they greatly improve sensitivity and specificity for diagnosis of AD. In AD the CSF Beta- amyloid 1-42 levels are low (300%), and this combination forms the "AD signature". These changes in Beta- amyloid 1-42 and total Tau protein levels occur in the preclinical phase and persist through the disease course and therefore are an early finding to assist diagnosis of AD. Low Beta- Amyloid 1-42 and high Total Tau Protein levels (AD Signature) used together may allow discrimination from healthy controls with level of sensitivity and specificity over 85%. Ref: Blennow et al. (2015). Alzheimers Dement. PMID: 24795085.