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Unit Code 83380:
Paraneoplastic Autoantibody Evaluation, Serum

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Method Description

Indirect Immunofluorescence Assay (IFA)

Before screening for neuronal nuclear and cytoplasmic

autoantibodies, patient's serum is preabsorbed with liver tissue

extract to remove nonorgan-specific autoantibodies. After

application to a composite substrate of frozen mouse tissues

(brain, kidney, and gut), washing, fluorescein-conjugated goat

antihuman IgG is applied to detect the distribution and pattern

of the patient's bound IgG. (Vernino S, Lennon VA: New Purkinje

cell antibody [PCA 2]:  marker of lung cancer related

neurological autoimmunity. Ann Neurol 2000;47:297-305;

Lennon VA:  The case for a descriptive generic nomenclature:  

classification of immunostaining criteria for PCA-1, ANNA-1,

and ANNA-2 autoantibodies. Neurology 1994;44:

2412-2415; Chan KH, Vernino S, Lennon VA:  ANNA-3

anti-neuronal nuclear antibody:  marker of lung cancer-related

autoimmunity. Ann Neurol 2001 September;50[3]:301-311; Yu Z,

Kryzer TJ, Griesmann GE, et al:  CRMP-5 neuronal autoantibody:  

marker of lung cancer and thymoma-related autoimmunity.

Ann Neurol 2001 February;49[2]:146-154)

 

Radioimmunoassay (RIA)

Goat antihuman IgG and IgM is used as precipitant in all assays.

Cation channel protein antigens are solubilized from neuronal

or muscle membranes, in non-ionic detergent and complexed

with a selective high-affinity ligand that is labeled with (125)I.  

(125)I recombinant human GAD65 is used as antigen to

confirm GAD65 autoantibody (when suspected from

immunofuorescent staining pattern). (Griesmann GE,

Kryzer TJ, Lennon VA:  Autoantibody profiles of

myasthenia gravis and Lambert-Eaton myasthenic syndrome.

In Manual of Clinical and Laboratory Immunology. 6th edition.

Edited by NR Rose, RG Hamilton, et al. Washington, DC, ASM

Press 2002, pp 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 December;73[12]:1161-1166)

 

Acetylcholine receptor modulating antibodies (muscle AChR)

are detected by incubating the patient's serum for 14 hours with

viable, noninnervated, monolayer cultures of human muscle cells.

Percent loss of surface AChR is then quantitated by probing with

(125)I-alpha-bungarotoxin. (Howard FM Jr, Lennon VA,

Finley J, et al: Clinical correlations of antibodies that bind, block,

or modulate human acetylcholine receptors in myasthenia gravis.

Ann NY Acad Sci 1987;505:526-538)

 

Enzyme Immunoassay (EIA)

A mixture of sarcomeric proteins extracted from innervated

rat skeletal muscle is used as antigen to detect striational

antibodies (IgG, IgM, and IgA). (Cikes N, Momoi MY,

Williams CL, et al:  Striational autoantibodies:

quantitative detection by enzyme immunoassay in

myasthenia gravis, thymoma, and recipients of D-penicillamine

or allogeneic bone marrow. Mayo Clin Proc 1988;63:474-481)

 

Western Blot (WB)

WB is performed when IFA screening is not interpretable

due to interfering  autoantibodies. A mixture of neuronal

antigens extracted aqueously from adult rat cerebellum is

denatured, reduced, and separated by electrophoresis

on 10% polyacrylamide gel (5% for PCA-2 and ANNA-3).

Full-length recombinant human CRMP-5 antigen is used to

confirm CRMP-5-IgG. (Yu Z, Kryzer TJ, Griesmann GE,

et al:  CRMP-5 neuronal autoantibody: marker of lung

cancer and thymoma-related autoimmunity.

Ann Neurol 2001 February;49[2]:145-154)

Performing Laboratory Location

Rochester

Key