Test Id : PNEFS

This test is only appropriate as a follow-up in patients who have a previous positive serum test result. If patients have not had a previous positive serum test result, order one of the following:

-AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum

-CDS1 / CNS Demyelinating Disease Evaluation, Serum

-CIDP / Chronic Inflammatory Demyelinating Polyradiculoneuropathy/Nodopathy Evaluation, Serum

-DYS2 / Dysautonomia, Autoimmune/Paraneoplastic Evaluation, Serum

-DMS2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Serum

-ENS2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-EPS2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Serum

-GID2 / Gastrointestinal Dysmotility, Autoimmune/Paraneoplastic Evaluation, Serum

-MAS1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-MDS2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Serum

-MGLE / Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum

-MGMR / Myasthenia Gravis Evaluation with Muscle-Specific Kinase (MuSK) Reflex, Serum

-NMS1 / Necrotizing Myopathy Evaluation, Serum

-PCDES / Pediatric Autoimmune Encephalopathy/CNS Disorder Evaluation, Serum

-SPPS / Stiff-Person Spectrum Disorders Evaluation, including Progressive Encephalomyelitis with Rigidity and Myoclonus, Serum

This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. The specific waiting period before specimen collection will depend on the isotope administered, the dose given, and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held 1 week and assayed if sufficiently decayed or canceled if radioactivity remains.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 4 mL

Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.

If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.

2 mL

Monitoring patients who have previously tested positive for one or more antibodies within the past 5 years in a Mayo Clinic Laboratories serum evaluation

Paraneoplastic autoimmune neurological disorders reflect a patient's humoral and cellular immune responses to cancer. The cancer may be new or recurrent, is usually limited in metastatic volume, and is often occult by standard imaging procedures. Autoantibodies specific for onconeural proteins found in the plasma membrane, cytoplasm, and nucleus of neurons or muscle are generated in this immune response and serve as serological markers of paraneoplastic autoimmunity. The most recognized cancers in this context are small-cell lung carcinoma, thymoma, ovarian (or related mullerian) carcinoma, breast carcinoma, and Hodgkin lymphoma. Pertinent childhood neoplasms recognized thus far include neuroblastoma, thymoma, Hodgkin lymphoma, and chondroblastoma. An individual patient's autoantibody profile can predict a specific neoplasm with 90% certainty but not the neurological syndrome.

Four classes of autoantibodies are recognized in serum analysis:

-Neuronal nuclear (antineuronal nuclear antibody-type 1 [ANNA-1], ANNA-2, ANNA-3)

-Neuronal and muscle cytoplasmic (Purkinje cell cytoplasmic antibody, type 1 [PCA-1], PCA-2, PCA-Tr, collapsin response-mediator protein-5 [CRMP-5], amphiphysin, and striational)

-Glial nuclear (antiglial nuclear antibody: AGNA)

-Plasma membrane cation channel antibodies (neuronal P/Q-type and muscle acetylcholine receptor autoantibodies). These autoantibodies are potential effectors of neurological dysfunction.

Patients who are seropositive usually present with subacute neurological signs and symptoms. The patient may present with encephalopathy, cerebellar ataxia, myelopathy, radiculopathy, plexopathy, sensory, sensorimotor, or autonomic neuropathy, with or without coexisting evidence of a neuromuscular transmission disorder: Lambert-Eaton syndrome, myasthenia gravis, or neuromuscular hyperexcitability. Initial signs may be subtle, but a subacute multifocal and progressive syndrome usually evolves. Sensorimotor neuropathy and cerebellar ataxia are common presentations, but clinical pictures in some patients are dominated by striking gastrointestinal dysmotility, limbic encephalopathy, basal ganglionitis, or cranial neuropathy (especially loss of vision, hearing, smell, or taste). Cancer risk factors include past or family history of cancer, history of smoking, or social/environmental exposure to carcinogens. Early diagnosis and treatment of the neoplasm favor less neurological morbidity and offer the best hope for survival.

*Methodology abbreviations:

CBA: Cell-binding assay

ELISA: Enzyme-linked immunosorbent assay

FACS: Flow cytometry

IB: Immunoblot

IFA: Immunofluorescence assay

RIA: Radioimmunoassay

Antibodies directed at onconeural proteins shared by neurons, muscles, and certain cancers are valuable serological markers of a patient's immune response to cancer. They are not found in healthy subjects and are usually accompanied by subacute neurological signs and symptoms. Several autoantibodies have a syndromic association, but no known autoantibody predicts a specific neurological syndrome. Conversely, a positive autoantibody profile result has 80% to 90% predictive value for a specific cancer. It is not uncommon for more than one paraneoplastic autoantibody to be detected, each predictive of the same cancer.

This test should only be utilized when the presence of paraneoplastic autoantibodies has been previously documented.

1. Lancaster E, Martinez-Hernandez E, Dalmau J. Encephalitis and antibodies to synaptic and neuronal cell surface proteins. Neurology. 2011;77(2):179-189

2. Horta ES, Lennon VA, Lachance DH, et al. Neural autoantibody clusters aid diagnosis of cancer. Clin Cancer Res. 2014;20(14):3862-3869

3. Gilligan M, McGuigan C, McKeon A. Paraneoplastic neurologic disorders. Curr Neurol Neurosci Rep. 2023;23(3):67-82. doi:10.1007/s11910-023-01250-w

4. Graus F, Vogrig A, Muniz-Castrillo S, et al. Updated diagnostic criteria for paraneoplastic neurologic syndromes. Neurol Neuroimmunol Neuroinflamm. 2021;8(4):e1014

Indirect Immunofluorescence Assay:

Before testing, patient's specimen is preabsorbed with liver powder to remove nonorgan-specific autoantibodies. After applying to a composite substrate of frozen mouse tissues (brain, kidney, and gut) and washing, fluorescein-conjugated goat-antihuman IgG is applied to detect the distribution and pattern of patient IgG binding.(Pittock SJ, Kryzer TJ, Lennon VA. Paraneoplastic antibodies coexist and predict cancer, not neurological syndrome. Ann Neurol. 2004;56[5]:715-719; Honorat JA, Komorowski L, Josephs KA, et al. IgLON5 antibody: Neurological accompaniments and outcomes in 20 patients. Neruol Neruoimmunol Neruoinflamm. 2017;4[5]:e385. doi:10.1212/NXI.0000000000000385)

Radioimmunoassay:

Goat-antihuman IgG and IgM are used as precipitants in all assays. Cation channel protein antigens are solubilized from neuronal or muscle membrane in nonionic detergent and complexed with a selective high-affinity ligand labeled with (125)I. (125)I-labelled recombinant human glutamic acid decarboxylase-65 (GAD65) antigen is used to confirm GAD65 autoantibody (when suspected from immunofluorescent staining pattern).(Griesmann GE, Kryzer TJ, Lennon VA Autoantibody profiles of myasthenia gravis and Lambert-Eaton myasthenic syndrome. In: Rose NR, Hamilton RG, et al, eds. Manual of Clinical and Laboratory Immunology. 6th ed. ASM Press, 2002:1005-1012; Walikonis JE, Lennon VA. Radioimmunoassay for glutamic acid decarboxylase [GAD65] autoantibodies as a diagnostic aid for stiff-man syndrome and a correlate of susceptibility to type 1 diabetes mellitus. Mayo Clin Proc. 1998;73[12]:1161-1166; Jones AL, Flanagan EP, Pittock SJ, et al. Responses to and outcomes of treatment of autoimmune cerebellar ataxia in adults. JAMA Neurol. 2015;72[11]:1304-1312. doi:10.1001/jamaneurol.2015.2378)

Cell Binding Assay:

Patient specimen is applied to a composite slide containing transfected and nontransfected HEK-293 or EU90 cells. After incubation and washing, fluorescein-conjugated goat-antihuman IgG is applied to detect the presence of patient IgG binding.(Unpublished Mayo method)

Flow Cytometry:

This method uses flow cytometry to measure the loss of acetylcholine receptor (AChR) molecules expressed on the surface of live cells expressing AChR on the cell surface. The cell line used is an immortalized human rhabdomyosacroma cell line that expresses endogenous muscle-type nicotinic AChR on its surface. Cells are plated in a 96-well plate and cultured 72 hours prior to the addition of patient serum for an additional 18-22 hours to enable internalization of AChRs (modulation). Modulation is then stopped by placing cells on ice. The amount of remaining AChRs on the cell surface is measured by flow cytometry. On ice, cells are incubated with a recombinant rat monoclonal antibody against alpha-subunit of the AChR followed by a secondary goat anti-rat IgG antibody conjugated with APC. The amount of AChR on the cell surface is proportional to the median fluorescence intensity (MFI) of APC. To calculate the amount of modulation (ie, % loss of AChR) the APC MFI is compared between cells treated with patient serum and cells treated with serum lacking AChR modulating antibodies. Background signal is established in each experiment utilizing cells stained with secondary antibody alone (no patient sera). The percent loss of AChR is calculated as 1-([Patient MFI-Background MFI]/[Negative calibrator MFI - Background MFI])*100%.(Unpublished Mayo method)

Immunoblot:

All steps are performed at ambient temperature (18-28 degrees C) utilizing the EUROBlot One instrument. Diluted patient specimen (1:12.5) is added to test strips (strips containing recombinant antigen manufactured and purified using biochemical methods) in individual channels and incubated for 30 minutes. Positive samples will bind to the purified recombinant antigen and negative samples will not bind. Strips are washed to remove unbound antibodies and then incubated with antihuman IgG antibodies (alkaline phosphatase-labelled) for 30 minutes. The strips are again washed to remove unbound anti-human IgG antibodies and nitroblue tetrazolium chloride/5-bromo-4-chloro-3-indolylphosphate (NBT/BCIP) substrate is added. Alkaline phosphatase enzyme converts the soluble substrate into a colored insoluble product on the membrane to produce a black band. Strips are digitized via picture capture on the EUROBlot One instrument and evaluated with the EUROLineScan software.(O'Connor K, Waters P, Komorowski L, et al. GABAA receptor autoimmunity: A multicenter experience. Neurol Neuroimmunol Neuroinflamm. 2019;6[3]:e552. doi:10.1212/NXI.0000000000000552)

Enzyme-linked Immunosorbent Assays:

Antiganglioside antibodies in specimens are detected by enzyme-linked immunosorbent assays (ELISA). Ganglioside antigens (GM1 and GD1b) adsorbed to wells of ELISA plates are incubated with patient's specimen or controls. The plates are washed, and alkaline phosphatase conjugated antihuman IgG or IgM antibodies (ie, secondary) are added in a second incubation. The wash step is repeated, and enzyme substrate is added. Absorbance is measured and results are expressed as antibody titer ie, the greatest dilution at which the absorbance of wells that contain patient sample is greater than 2.0 times the mean absorbance of normal sample tested simultaneously.(Taylor BV, Gross L, Windebank AJ. The sensitivity and specificity of anti-GM1 antibody testing. Neurology. 1996;47:951-955; McKeon A, Lennon V, LaChance DH, et al. Striational antibodies in a paraneoplastic context. Muscle Nerve. 2013;47[4]:585-587)

Varies

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This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

83519 GANG (if appropriate)

86043 ACMFS (if appropriate)

84182 AGNBS (if appropriate)

86255 AINCS (if appropriate)

86255 AMPCS (if appropriate)

86255 AMPHS (if appropriate)

84182 AMIBS (if appropriate)

84182 AN1BS (if appropriate)

84182 AN2BS (if appropriate)

86255 AGN1S (if appropriate)

86255 ANN1S (if appropriate)

86255 ANN2S (if appropriate)

86255 ANN3S (if appropriate)

86255 APBCS (if appropriate)

86255 APBIS (if appropriate)

86255 CS2CS (if appropriate)

86255 CRMS (if appropriate)

86255 DPPCS (if appropriate)

86255 DPPIS (if appropriate)

86255 GABCS (if appropriate)

86255 GFACS (if appropriate)

86255 GFAIS (if appropriate)

86255 GRFCS (if appropriate)

86255 GRFIS (if appropriate)

83516 IGG_D (if appropriate)

86255 IG5CS (if appropriate)

86255 IG5IS (if appropriate)

83516 IGM_D (if appropriate)

83516 IGM_M (if appropriate)

86255 ITPCS (if appropriate)

86255 ITPIS (if appropriate)

86255 LG1CS (if appropriate)

86255 GL1CS (if appropriate)

86255 GL1IS (if appropriate)

86255 NCDCS (if appropriate)

86255 NCDIS (if appropriate)

86255 NFHCS (if appropriate)

86255 NIFIS (if appropriate)

86255 NFLCS (if appropriate)

86255 NMDCS (if appropriate)

83519 CCPQ (if appropriate)

84182 PC1BS (if appropriate)

84182 PCTBS (if appropriate)

86255 PCABP (if appropriate)

86255 PCAB2 (if appropriate)

86255 PCATR (if appropriate)

86255 PDEIS (if appropriate)

86255 SP5CS (if appropriate)

86255 SP5IS (if appropriate)

86255 SP7CS (if appropriate)

86255 SP7IS (if appropriate)

86255 SRPIS (if appropriate)

84182 SRPBS (if appropriate)

86255 T46CS (if appropriate)

86255 T46IS (if appropriate)