Autoimmune Inner Ear Disease (AIED) or Menieres disease part-2
The lymphocyte transformation assay, like the anti-cochlear antibody test, is presently of uncertain value.
Antiendothelial antibodies may be associated with some cases of AIED (Cadoni et al, 2003). At this writing there is no commercially available test.
Several studies have reported an association between autoimmune thyroid disease and ear disease (Brenner et al, 2004; Medugno et al, 2000), which is the rationale for testing for anti-microsomal or thyroid peroxidase antibodies.
It has recently been reported that antibodies to sulfoglucuronosyl glycolipids are common in autoimmune inner ear disease. (Yamawaki M, 1998). It remains to be seen if this finding will be confirmed and whether a commercial assay will be developed.
At this writing (1/2003), it is not generally felt thatanti cochlear antibody(also called anti-HSP70) blood tests are specific enough to be very useful. Antibodies to HSP-70 can also be found in Lyme disease, ulcerative colitis, cancers, and in about 5% of healthy individuals. Yeom et al (2003) recently suggested that all anti-HSP tests are directed against the wrong substrate. Whether this is true or not, because of the poor specificity of anti-HSP 70 testing, diagnosis is generally based on evidence from broader tests of autoimmunity, or a positive response to steroids.
A small study recently suggested that FDG PET scans may be useful in AIED. (Mazlumzadeh et al, 2003). More investigation of this modality is needed before it's role in diagnosis can be defined.
As there are no specific tests for AIED, a common approach is to look for other evidence for autoimmune involvement.
Blood tests for autoimmune disorders, ordered from most to least useful, include:
- Sed Rate and CRP
- Thyroid (anti-microsomal and thyroglobulin antibodies)
- Rheumatoid Factor
- Complement C1Q
- anti-gliadin and anti-endomysial antibodies (for Celiac disease)
Blood tests for conditions that resemble autoimmune disorders, again from most to least useful, include:
- FTA (for SYPHILIS )
- HBA1C (for diabetes, which is often autoimmune mediated also)
- HIV (HIV is associated witha ear nerve damage as well as syphilis)
- Lyme titer
How is Autoimmune Inner Ear Disease Treated ?
Classic treatments with steroids and immunosuppressants
IVIG is the best treatment.
Pulse steroids useful
may be beneficial . Plasmapheresis requires periodic visits using a machine similar to a dialysis unit.
Methotrexate, a chemotherapy and arthritis drug, has been shown to be ineffective in a large multicenter study (Harris et al, 2003).
Anti-TNF drugs and etanercept
Enbrel is given as an subcutaneous injection twice/week. Enbrel has generally been well tolerated but according to the manufacturer's information, people on Enbrel have developed serious infections (2%), nervous system disorders, and depression/personality disorders (1%).
A related agent, (infliximab) Remicade, was not found useful for AIED, but this study was based on only a handful of cases (Pyykko et al, 2002). Remicade is also not suitable for home use. There are newer agents that are in the drug pipeline that will need to be tested for their efficacy. Of the newer anti-TNF drugs, the most interesting is Humira, which is another anti-TNF drug, which was recently approved by the FDA (12/2002). It is not known so far whether this drug is useful in AIED.
Drugs already available in the world that are also anti-TNF agents include thalidomide, pentoxifylline (a vasodilator used for poor circulation), and rolipram (an antidepressant available in Japan and Europe). These drugs have not been tried in AIED.
None of these drugs has an official FDA indication for AIED. There recently has been some concern about these drugs affecting other health problems such as how well the body fights infection or kills tumor cells. In controlled studies of all TNF-alpha blocking drugs, more cases of lymphoma have been noted in treated patients than controls. Lymphomas are also often seen with use of other immunosuppresants. It is also generally felt that when these drugs are in use there should be increased vigilance for reactivation of tuberculosis.
In animals, attempts have been made to treat variants of AIED with oral collagen (Kim et al, 2001). Relapsing polychondritis is a disorder in which there may be antibodies to collagen and acquired deafness.