Myasthenia gravis and alopecia areata
Myasthenia gravis is a chronic progressive disease caused
by a deficiency of acetylcholine [a neurotransmitter] at the neuromuscular
junctions. It is characterized by chronic fatigue and muscular
weakness, especially in the face and neck region. Patients affected
with myasthenia gravis often have autoimmune skin disorders and
they are seen to be affected by alopecia areata too. Hence, a
study to understand the relationship between myasthenia gravis
and alopecia areata was conducted on 159 Japanese myasthenia gravis
patients comprising of 75 men and 84 women. These patients were
diagnosed with myasthenia gravis following clinical, physiological
and immunological tests and assessed for the condition based on
the recommendations put forth by the myasthenia gravis foundation
of America.
Patients were evaluated for thymoma and thymectomy was performed
on some patients. All were tested for serum levels of anti-acetylcholine
receptor antibodies. Thymoma is an epithelial neoplasm or tumor
of the thymus gland. It can be benign [in an encapsulated form]
or rarely invasive. Thymomas are mostly slow growing tumors and
about 15% of patients with Myasthenia gravis are seen to be affected
by them. The surgical removal of the thymus gland is done by a
procedure known as thymectomy. The thymus gland has a major role
to play in the body’s immune system and is large during
childhood but regresses during the onset of adulthood. Since the
immune system is already established by the time an individual
progresses towards adulthood, the removal of the thymus does not
significantly affect the immune system of the patient. By way
of thymectomy, the Myasthenia gravis patient’s weakness
is greatly reduced and so is the medication required to treat
the disease.
Using Polymerase Chain Reaction [PCR] and Restriction Fragment
Length Polymorphism [RFLP] methods, alleles of human leukocyte
antigen (HLA) DQB-1 and DRB-1 genes were analyzed. All the experimental
results were statistically analysed.
The results of the whole study are as follows:-
1. Amongst the 159 patients, 6 had a family history for alopecia
areata of which 3 had alopecia totalis and all of them developed
alopecia areata after myasthenia gravis was clinically diagnosed.
2. 129 of the patients tested positive for serum anti-acetylcholine
receptor antibodies and the levels were higher when myasthenia
gravis was associated with Alopecia areata.
3. Alopecia areata in some patients was due to lymphocyte infiltration
in the peribulbular region of the hair shaft which was ascertained
by histological studies. The number of cells was higher in patients
who had developed alopecia areata after myasthenia gravis as compared
to those who had only myasthenia gravis.
4. In this study 89 patients underwent thymectomy out of which
44 had confirmed thymoma. When alopecia areata was also diagnosed,
an advanced stage of thymoma was very common in these patients
and only 1 patient out of the 6 had no thymoma. 2 of the 5 had
recurring thymoma. The one who did not have thymoma and 2 others
with thymoma were treated with topical corticosteroids and they
showed marked improvement in their hair loss condition. The remaining
3 were given oral corticosteroids as art of immunosuppressive
therapy but they failed to respond to their alopecia totalis condition.
5. Amongst the 6 patients with both myasthenia gravis and alopecia
areata, 3 had alopecia totalis, 1 had giant cell myocarditis [inflammation
of the muscular tissue of the heart] and myositis [inflammation
of muscle tissue] and the rest 2 had pure red cell aplasia.
6. The patient who had myocarditis and was on oral corticosteroids
expired due to his inflammatory condition of the heart. The other
2 patients are alive even after 4-12 years after alopecia areata
onset.
7. HLA class II gene alleles are seen to be associated with patients
with myasthenia gravis and both myasthenia gravis and alopecia
areata. So the relative frequencies of the alleles DRB1 and DQB1
were studied in 6 patients with myasthenia gravis and alopecia
areata and 82 patients with only alopecia areata. The DQB1-0301
allele was reported to be associated with alopecia areata in Caucasians
while DQB1-0402 was associated with Japanese who have myasthenia
gravis with thymoma. None of the patients under study had any
of these two.
DRB1-0901 and DQB1-0303 were observed to be frequent in patients
with alopecia areata and these two haplotypes are seen frequently
in the Japanese population. There is no concrete evidence about
the percentage prevalence of myasthenia gravis and alopecia areata
in Caucasian and Japanese populations, but the report suggests
that the percentage may be higher in Japanese due to these haplotypes.
Many patients develop alopecia areata independent of myasthenia
gravis. Myasthenia gravis is an auto-antibody mediated disease
while alopecia areata is mediated by CD8+ T cells, that infiltrate
into the hair follicles, supported by CD4+ cells. However in this
study, since most of the auto-immune diseases developed after
the myasthenia gravis patients underwent thymectomy and peripheral
blood cells were also affected, an intensive study on the T-cell
mechanism may be helpful in finding the appropriate solution to
patients afflicted with both the diseases.
Myasthenia gravis and alopecia areata references
- Suzuki S, Shimoda M, Kawamura M, Sato H, Nogawa
S, Tanaka K, Suzuki N, Kuwana M. Myasthenia
gravis accompanied by alopecia areata: clinical and immunogenetic
aspects. Eur J Neurol. 2005 Jul;12(7):566-70.
PMID: 15958099
- Kamada N, Hatamochi A, Shinkai H. Alopecia areata associated
with myasthenia gravis and thymoma: a case of alopecia with
marked improvement following thymectomy
and high level prednisolone administration. J Dermatol. 1997
Dec;24(12):769-72.
PMID: 9492440
- Korn-Lubetzki I, Virozov Y, Klar A.
Myasthenia gravis and alopecia areata. Neurology. 1998 Feb;50(2):578.
No abstract available.
PMID: 9484415
- Kubota A, Komiyama A, Hasegawa O.
Myasthenia gravis and alopecia areata. Neurology. 1997 Mar;48(3):774-5.
PMID: 9065564
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