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Test Code AN2TC Antineuronal Nuclear Antibody Type 2 (ANNA-2) Titer, Spinal Fluid


Ordering Guidance


For investigating a smoker presenting with 1 or more elements of encephalomyeloradiculoneuropathy, order PAVAL / Paraneoplastic Autoantibody Evaluation, Serum.

 

Serum is preferred. Spinal fluid testing is particularly useful when interfering antibodies are present in the serum.



Specimen Required


Only orderable as a reflex. For more information see:

-DMC2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-ENC2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-EPC2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

 

Container/Tube: Sterile vial

Specimen Volume: 2 mL


Useful For

Investigating middle-aged or older patients who present with unexplainable signs of midbrain/cerebellar/brain stem disorder and/or myelopathy, especially women with a previous history of breast cancer, and both sexes if there is a history of tobacco abuse or passive exposure

 

Reporting an end titer result from cerebrospinal fluid specimens

Method Name

Only orderable as a reflex. For more information see:

-DMC2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-ENC2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-EPC2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

 

Indirect Immunofluorescence Assay (IFA)

Reporting Name

ANNA-2 Titer, CSF

Specimen Type

CSF

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Clinical Information

Antineuronal nuclear autoantibody type 2 (ANNA-2), also known as anti-Ri, is an IgG serologic marker of paraneoplastic neurologic autoimmunity and reflects an immune response to neuronal antigens expressed in certain breast, lung, or gynecologic cancers. These carcinomas are often occult, with the patients presenting with unexplained signs of neurologic dysfunction. ANNA-2 is far less common than ANNA-1. It is one of the rarest paraneoplastic antibodies encountered in the Mayo Clinic Neuroimmunology Laboratory.

 

Patients who are seropositive for ANNA-2 usually present to a neurologist with signs of midbrain, brain stem, cerebellar, or spinal cord dysfunction. Some have sensorimotor neuropathy. Ocular opsoclonus-myoclonus, laryngospasm, or jaw-opening dystonia may be prominent. Peripheral neuropathic signs and symptoms may occur. These often reflect coexisting autoimmunity to other onconeural proteins (eg, ANNA-1, collapsin response-mediator protein-5 [CRMP-5], calcium channels); coexisting paraneoplastic autoantibodies are found in 73% of cases.

 

ANNA-2 positive patients are female in 64% of cases. Most have a primary carcinoma of breast or lung; gynecologic cancer is less frequent.

 

Treatment of the cancer can lead to progressive reduction in ANNA-2 titer and stabilization or striking improvement of the neurologic disorder.

 

ANNA-2 is not detected in serum or spinal fluid of healthy individuals. It is found in fewer than 2% of patients who have small-cell lung carcinoma without evidence of neurologic dysfunction.

 

ANNA-2 is identified by an indirect immunofluorescence assay. It characteristically stains neurons in the central nervous system and spares neurons in the peripheral nervous system. ANNA-2 is also identifiable by neuronal Western blot characteristics.

Reference Values

Only orderable as a reflex. For more information see:

-DMC2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-ENC2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-EPC2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

 

<1:2

Neuron-restricted patterns of IgG staining that do not fulfill criteria for antineuronal nuclear antibody type 2 may be reported as "unclassified antineuronal IgG." Complex patterns that include nonneuronal elements may be reported as "uninterpretable."

Day(s) Performed

Monday through Sunday

Report Available

5 to 8 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

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.

CPT Code Information

86256