Autoimmune Inner Ear
Disease (AIED)
Timothy MD
Page
last modified:
January , 2008
A
new name for a well known
old ear disease is AIED.
That is Autoimmune inner ear
disease or "AIED" consists
of a syndrome of sudden
hearing loss which may be
accompanied by dizziness
which is caused by
antibodies or immune cells
which are attacking the
inner ear.
The
classic picture consists of
sudden attacks of pain in
the ear accompanied by loss
of hearing which happens
quickly may be accompanied
by tinnitus (ringing,
hissing, roaring) these
attacks remit and relapse.
The patient gets better and
then improves. Variants are
bilateral attacks of hearing
loss and tinnitus which
resemble Meniere's disease,
and attacks of dizziness
accompanied by abnormal
blood tests for
self-antibodies. About 50%
of patients with AIED have
imbalance. The attacks can
last a few days or a few
weeks.
The
immune system consists of a
number of cells to defend
the human cells from being
attacked by invaders.
However the invaders learn
that by using the very own
defence forces of the human
body a attck can be mounted
and there are several ways
that it can damage the inner
ear. Both allergy and
traditional "autoimmune
disease" such as Ankylosing
spondylitis (bamboo spine),
Behcet's (oro genetial
ulceration), Systemic Lupus
Erythematosis (SLE or
lupus), Sjoegren's syndrome
(dry eye syndrome), Cogan's
disease, ulcerative colitis,
Wegener's granulomatosis
(cherry red gums), relapsing
polychondritis, rheumatoid
arthritis, and scleroderma
(tight lips and fingers) can
cause or be associated with
AIED.
Allergy involving the inner
ear is traditionally felt to
be food related, but there
is presently no agreement as
to the importance of food
allergy.
Ankylosing spondylitis (AS)
is a progressive bone
disease associated with
fusion of the spine. Persons
with severe cases of AS may
be disabled because of their
lack of flexibility.
Although one might expect AS
to be associated with
conductive hearing loss, AS
has been reported to be
associated with a
sensorineural hearing loss
in about 28% of patients (
Alatas, Yazgan et al. 2005 )
Susac syndrome (microangiopathy
of ear, brain and eye) is a
disorder in which deafness,
reduced vision, and
encephalopathy may all
present simultaneously. The
encephalopathy manifests
with headache, confusion,
memory loss, behavioral
changes, dysarthria and
occasional mutism. The
hearing loss is usually
bilateral and accompanied by
tinnitus and vertigo.
According to Susac, it is
generally a low-frequency
sensorineural loss,
resembling that of
Meniere's disease. The
reduced vision is caused by
retinal artery occlusions.
MRI images, which are
invariably abnormal, reveal
multifocal white matter
lesions, including the
corpus callosum (Susac et
al, 2004). This is an
unusual location for a white
matter lesion as it is not
found in the more common
types of demyelinating
disease, such as MS.
Treatment is with
immunosuppresants (Clement
et al, 2003).
Not
all individuals with
bilateral sensorineural
hearing loss have autoimmune
disease.
Genetic defects,
infections,
toxins, advanced age,
noise exposure, and
conditions of mysterious
origin all account for
some cases.
How Common is Autoimmune
Inner Ear Disease ?
AIED is rare, probably
accounting for less than 1%
of all cases of hearing
impairment or dizziness. The
precise incidence is
controversial. About 16% of
persons with bilateral
Meniere's disease, and
6% of persons with Meniere's
disease of any variety may
be due to immune
dysfunction.
What Causes Autoimmune
Inner Ear Disease ?
The
cause of AIED is generally
assumed to be related to
either antibodies or immune
cells that cause damage to
the inner ear. There are
several theories as to how
these might arise,
analogously to other
putatative autoimmune
disorders:
Bystander damage:
In this theory damage to the
inner ear causes cytokines
to be released which
provoke, after a delay,
additional immune reactions.
This theory might explain
the attack/remission cycle
of disorders such as
Meniere's disease. There is
evidence for cytokines in
the cochlea including
interleukin-1A, TNF-alpha,
NFkB P65 and P50, and IkBa
(Adams, 2002). Drugs that
block TNF such as etanercept
(see treatment section) seem
to be potentially effective
in AIED (Rahmen et al,
2001). The endolymphatic sac
lumen expresses TNF-alpha
(Satoh et al, 2003), which
may be another way wherebye
Meniere's disease is linked
to AIED. Other autoimmune
disorders such as Crohn's
disease also seem to be
linked to TNF, and other ear
diseases such as
otosclerosis also are
linked to TNF-alpha.
(Karosi, Konya et al. 2005)
Cross-reactions: In
this theory, antibodies or
rogue T-cells cause
accidental inner ear damage
because the ear shares
common antigens with a
potentially harmful
substance, virus or bacteria
that the body is fighting
off. This is presently the
favored theory of AIED.
COCH5B2 has recently been
reported to be a target
antigen in AIED (Boulassel
et al, 2001).
Intolerance: The
ear, like the eye may be
only an partially "immune
privileged" locus, meaning
that the body may not know
about all of the inner ear
antigens, and when they are
released (perhaps following
surgery or an infection),
the body may wrongly mount
an attack on the "foreign"
antigen.
In
the eye, there is a syndrome
called "sympathetic
ophthalmia", where
following a penetrating
injury to one eye, the other
eye may go blind. The
corresponding situation in
the ear would be to go deaf
in one ear, following trauma
or surgery performed on the
opposite ear. This theory is
not presently in favor for
the ear. Nevertheless, over
about 20 years of practice
the author of this page has
seen several patients who
develop ear disease in a
delayed fashion in the
opposite ear treated for an
acoustic neuroma,
including one patient
following gamma knife
"surgery". There have also
been cases reported of
development of AIED in the
opposite ear after surgery
for
Meniere's disease (Ochoa
and Weider, 2003), 11 years
after a temporal bone
fracture (ten Cate and
Bachor, 2005), and in 2 of
148 patients after stapes
surgery (Richards et al,
2002). Lacking much
organized data other than
the stapes study, and
considering our personal
observations, we suspect
that this occurs in about 1%
of patients in which inner
ear antigen is released into
the body.
Genetic factors: There is
evidence that genetically
controlled aspects of the
immune system may increase
or otherwise be associated
with increased
susceptibility to common
hearing disorders such as
Menieres disease. Bernstein
and associates reported that
44% of patients with
Menieres,
otosclerosis and
striatal presbyacusis had
one particular extended MHC
haplotype
(Dqw2-Dr3-c4Bsf-C4A0-G11:
15-Bf:0.4-C2a-HSP70:7.5-TNF),
compared to only 7% of
controls. Sudden hearing
loss in Koreans that does
not recover is also
associated with HLA-DRB1*04,
DQA1 03 and 05 (Yeo et al,
1999; Yeo et al, 2001). The
author has also found an
association (in the US) with
certain types of HLA-types
and variants of vertigo in
caucasians (unpublished). On
the other hand, a recent
study by Lopez-Escamez and
others performed in Spain
found no difference in HLA
antigens between 54 patients
with definate MD and 534
normal controls (Lopez
Escamez et al, 2002). The
genetic background of HLA
studies is important and it
is possible that one group
might find HLA differences
which are not found in
another.
These data are thus
conflicted. If there is
indeed an association with
HLA, at least in certain
populations, it would
suggest that more of
Menieres disease and other
progressive syndromes may be
caused by immune dysfunction
than is presently generally
thought. It is important to
remember that HLA-typing is
relevant when considered in
the context of the patient's
genetic background. In other
words, studies of Korean
subjects for example, such
as reported by Yeo, may not
apply to persons of
non-Korean ethnicity.
How is the diagnosis of
Autoimmune Inner Ear Disease
made?
The
diagnosis is based on
history, findings on
physical examination, blood
tests, the results of
hearing and vestibular
tests, MRI scans, and
response to
immunosuppressive
medications. The usual
clinical picture is a
subacute bilateral
progressive
sensorineural hearing loss.
As
auditory neuropathy can
present with a progressive
bilateral sensorineural
hearing loss,
ABR testing should be
done in persons with enough
hearing for the test to be
practical. Otoacoustic
emmission tests should be
done in those in whom ABR
testing cannot be done. MRI
scans ot the brain are
useful to diagnose Susac's
syndrome (see above), as
well as to exclude possible
confounding disorders, such
as acoustic neuroma.
While specific tests for
autoimmunity to the inner
ear would be desirable, at
this writing (7/2004) there
are none that are both
commercially available and
proven to be useful. (Garcia
Berrocal et al, 2002).
Immunoflourescence of
supporting cells of guinea
pig organ of Corti (cochlea)
has also been shown to
correlate with disease and
steroid responsiveness.
According to Gray and
others, immunoflourescence
is more sensitive and
specific (86%, 41%) than is
Western Blot (59%, 29%)
(Gray and others, ARO
abstracts, 1999, #246).
Western Blot is helpful in
some hands (Garcia et al,
2003). Yeom et al (2003)
recently reported that
immunoflourescence is more
sensitive and specific than
anti-HSP 70. The specificity
of both tests to us seems
unacceptably low.
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 that
anti-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
-
ANA
-
Thyroid (anti-microsomal
and thyroglobulin
antibodies)
-
Rheumatoid Factor
-
Complement C1Q
-
Smooth Muscle Antibody
-
anti-gliadin and anti-endomysial
antibodies (for Celiac
disease)
-
HLA testing, especially
for HLA-B27
-
Raji-Cell
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
with
auditory neuropathy
as well as syphilis)
-
Lyme titer
How is
Autoimmune Inner Ear Disease
Treated ?
Classic treatments with
steroids and
immunosuppresants
There are several protocols
for treatment. In cases with
a classic rapidly
progressive bilateral
hearing impairment, a trial
of steroids (prednisone or
dexamethasone) for 4 weeks
may be tried. In persons
with response to steroids,
in most cases a chemotherapy
type of medication such as
Cytoxan will be used over
the long term (Sismanis et
al , 1994; Sismanis et al,
1997), as long term
high-dose steroids can
result in severe side
effects. In the author's
practice, persons who
respond to steroids are
considered for treatment
with Enbrel (see below), but
this is presently not
commonly used.
Plasmapheresis may be
beneficial (Luetje and
Berliner, 1997; Hussain et
al, 2005). 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
Etanercept (Enbrel) is
emerging as a promising
agent for treatment of AIED
(Rahmen et al, 2001; Wang et
al, 2003). Enbrel is an
anti-TNF (tumor necrosis
factor) drug. TNF is an
inflammatory cytokine (see
above). Wang et al recently
reported that etanercept
given acutely in sterile
experimental labyrinthitis
resulted in much better
hearing results in an animal
model. On the other hand,
Cohen et al recently
reported that Enbrel was no
better than placebo in
persons with chronic AIED.
In
our clinical practice,
we have had generally very
good results in our patients
with steroid responsive,
progressing AIED and we feel
that because of the study
design (chronic hearing
loss, no requirement for
steroid response), that
Enbrel is still worth
trying.
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.
Other approaches
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.
Treating aied
Research is needed on AIED
Autoimmune inner ear disease
is rare, making it difficult
to study. One can speculate
that there might be
effective treatments that
simply have not been
discovered. For example,
there are numerous potential
treatments that have not
been tried in a formal way.
Gamma globulin infusions,
given monthly, are useful in
numerous autoimmune
disorders. This treatment is
very expensive, which limits
its use. Immune modulating
drugs such as are used for
treatment of MS
(beta-interferon, alpha-inteferon,
copaxone) have not been
tried in AIED, to this
author's knowledge. Other
medications that have
coincidental suppression of
immune responses, such as
minocycline, or other anti-TNF
drugs (see above), might be
tried.
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