Anti-musk antibodies: useful test for the diagnosis of myasthenia gravis
Through a simple blood draw it is possible to monitor various parameters of our state of health. Among these we also find anti-musk antibodies , the dosage of which is often considered and analyzed for the diagnosis of myasthenia gravis .
We are talking about autoantibodies which in normal conditions are not detectable in the bloodstream but which, as we will see, are useful for the diagnosis of myasthenia gravis .
But what exactly is this exam about? How does it work ? What are the normal values ? What, on the other hand, are the values you need to worry about? When is anti-musk antibody testing prescribed ?
Let’s try to answer all these questions together.
What are anti-musk antibodies?
With anti-muSK antibodies we refer to the anti-muscle-specific tyrosine kinase antibodies and these are particular autoantibodies aimed at the musk proteins found at the level of the neuromuscular junction.
Basically, these autoantibodies produced by our immune system prevent the stimulation of muscles mediated by a neurotransmitter essential for our body, acetylcholine.
By preventing the activation of these receptors for this neurotransmitter, anti-musk antibodies cause severe muscle fatigue, precisely because of the lack of communication between the skeletal muscle and the nerves.
This leads to a very serious autoimmune disease known as myasthenia gravis. But the presence and production of these anti-musk antibodies are not the only cause of this pathological condition but, as we will see in today’s guide, the examination is of fundamental importance for the diagnosis of this disease.
What is the anti-musk antibody test for?
Under normal conditions, these particular antibodies are not found in the bloodstream. In fact, as we have already said, these are autoantibodies that are produced in very specific situations and which subsequently remain in the patient’s blood flow.
Intuitively, the examination for the dosage of anti-musk antibodies is indispensable when there is a suspicion of myasthenia gravis and is often associated with the examination of the anti-AcHR antibodies which concerns the acetylcholine receptors.
These two blood tests, if performed one after the other, can lead the doctor to establish a very precise clinical picture, and, depending on the outcome of each one, can evaluate the possibility of subjecting the patient to further in-depth tests.
In fact, in the event that the subject reports a total absence of both antibodies, he could still be affected by the disease, but the causes are different from those that have been investigated.
When is this test prescribed?
As you may have guessed, the test in question is requested when the doctor suspects that the patient has myasthenia gravis . Usually this suspicion derives from the manifestation of the symptomatological picture that accompanies the disease.
The most common symptoms of myasthenia gravis include the following:
- double vision;
- Difficulty swallowing and chewing;
- Feeling of suffocation;
- Drooping eyelid;
- Difficulty controlling eye movements;
- stammering;
- Problems involving the respiratory system;
- Tongue atrophy;
- Facial atrophy;
- Difficulty keeping the head up and straight;
- Anomalous burr formation;
- He retched;
- The neck muscles are weak;
- Difficulty walking;
- Variations in gait;
- Weakness in muscles;
- Inability to make long-term efforts.
How does the anti-musk antibody test work?
Since we are dealing with the dosage of a substance found in the blood, you will surely have understood that this is an examination that involves taking blood, generally from the arm.
Usually, specific preparation is not necessary for this type of exam, but we advise you to get more information from your trusted analysis laboratory.
What are the reference values?
Before explaining the reference values for this exam, remember that each laboratory can have a criterion that differs (even minimally) from that of another. Therefore, we advise you to rely only and exclusively on the data contained in your report.
Beyond this, generally, it is considered as:
- Success a value equal to or greater than 1:20;
- A value of 1:10 is doubtful ;
- Negative result a value of zero which basically indicates the absence of these antibodies in the blood.
What is myasthenia gravis?
We have talked so far about this disease known as myasthenia gravis , and it is now time to investigate the pathology better, to understand what it is, especially if our anti-musk antibody test has reported a positive result .
As we have already mentioned, myasthenia gravis is a particular autoimmune disease in which there is an inability of the motor nerve to send contraction signals to the muscle.
For this reason, the pathology in question is characterized by strong weakness and muscle fatigue. Precisely these two characteristics of the disease are aggravated every time a certain muscle group is put under strain.
At the same time, as the individual rests (or at any rate the muscle group is rested for some time), the situation improves.
In practice, it is a very debilitating disease for those who suffer from it and can worsen until it becomes fatal. This happens when the muscles of the respiratory district are involved, making even the simple act of breathing difficult.
Furthermore, it is very important not to confuse it with another pathological condition which often manifests itself with the same symptomatological picture: congenital myasthenic syndrome.
Currently there are no definitive cures for this disease, pharmacological treatments in fact plan to decrease the aggressive response of the immune system, but we will deal with this topic later.
What is myasthenia gravis caused by?
Unfortunately, we are not yet able to identify in detail the underlying causes of this serious autoimmune disease.
What is certain is that the main problem of this pathological condition, as we have already said, concerns a real interruption of communication between the nervous and muscular tissues.
In adults suffering from myasthenia gravis , a connection has often been found with the presence of an enlarged thymus or even a tumor in this organ which is responsible for producing some cells of the immune system.
How is myasthenia gravis treated?
Previously we have already talked about the fact that currently there are no specific treatments for myasthenia gravis , however it is possible to manage the symptoms thanks to a particular therapeutic treatment.
To keep the symptoms of the disease under control, which can often complicate the life of those who suffer from it, doctors usually advise the following points to be taken into account:
- Taking immunosuppressant drugs that help inhibit the production of the autoantibodies responsible for the disease. Among these drugs we mention above all cyclosporine, azathioprine and methotrexate which, even if they manage to considerably reduce the symptoms of the pathology, can have various side effects;
- It would be advisable to change one’s lifestyle , focusing on reducing any physical efforts, and allowing oneself the right rest;
- Intravenous administration of immunoglobulins helps to reduce the symptoms of the disease, but, unfortunately, for a short time. In this case we are dealing with a rather expensive treatment but, especially in the case of severe respiratory crises, it can save lives;
- Consider a thymectomy which consists in surgically removing the thymus in order to improve the situation from a symptomatic point of view. This procedure is not suitable for all patients suffering from myasthenia gravis, so we always advise you to ask your doctor for an opinion before making any kind of decision;
- The administration of cholinesterase inhibitors , i.e. a particular enzyme that is capable of degrading the neurotransmitter acetylcholine. These inhibitors are capable of improving muscle strength, albeit temporarily (usually the effect lasts up to four hours), but if taken regularly throughout the day they will improve your situation. Among these drugs we remember above all the Pyridostigmine which helps to increase the ability of the neurotransmitter acetylcholine in competing with the autoantibodies responsible for the disease. Even in this case, however, more or less serious side effects may appear, so a combined therapy is often prescribed to balance the situation;
- Undergo a plasmapheresis procedure which consists in separating the plasma part of the blood and cleaning it. In this way the level of autoantibodies circulating in the patient’s body decreases considerably and, consequently, also the symptoms of the disease. However, this procedure is not recommended as a long-term treatment;
- A therapy based on corticosteroids that help stimulate the synthesis of more AChRs in muscle cells. Corticosteroids, in fact, are famous for suppressing the activity of the immune system and, consequently, also the production of antibodies that attack the acetylcholine receptor. Unfortunately, here too there is a high risk of experiencing side effects.
She defines herself as curious by nature. In 2006 she graduated with honors in Biotechnology at the Sapienza University of Rome. Between 2005 and 2009, she carried out a university internship and research activity in the field of tumor immunotherapy. She is a co-author of three scientific publications. Since 2007 you have associated your passion for science with that for the web, starting the management of the FitnessEquilibrium.com project.