Mike, I'm sure it's very frustrating to not have the answers you need. Perhaps you do need a new doctor, one who doesn't mind a patient asking questions.
Before you had drugs and were newly diagnosed, did you feel worse than you do now? Have the drugs helped? There's the possibility that the drugs are harming your immune system and, therefore, making it harder to fight MG. Drugs can be helpful but our bodies work in concert with them.
Also, as you age, the body has a harder time with immunosuppressants. Our organs, like the liver and kidneys, age too!
Since they are the cleansers of the body, it's important for a doctor to always check to see if they are helping rid the body of what it doesn't want too. And while your doctor might do a million vials of blood, that doesn't mean that the "right" tests are being done or that another type of doctor wouldn't be useful in taking a look at all of those results (like an internist).
And I still have to wonder if something else is going on that is revving up your immune system.
As Dr. Howard, et. al., states below, antibody levels do not necessarily correlate with disease severity - which I'm sure you know. So, that's why I asked in my other post . . . How are you feeling? A clinical exam is crucial to MG because it IS a clinical diagnosis and the clinical exam is the best way to evaluate a patient (when done well). You can't tell how a patient is doing when they've been sitting quietly in a doctor's office. They have to see us MOVING in order to "get it." That's one reason Dr. Howard will often do exercise exams with PT, before and after Mestinon, to objectively see how patients are doing. Very smart!
This might look pedantic, but HOW antibodies are produced is an important factor for a doctor to consider. You may want to consult with an immunologist. There might be precursors in your body that are running amuck that have nothing to do with the disease state itself.
This might be helpful to look at the many variables of antibody development.
Have they checked your IgG subclasses? There are 4 subclasses of IgG. Here's Dr. Howard's article.
Mike, I have no idea what your other medical conditions might be or what other drugs you're on. What would be helpful is for someone to do a thorough examination of all of that and if something is indeed making your overall immune system worse.
Try not to focus on the "many" MG antibodies but on how you feel. IMO, you really need to find a doctor or two who cares enough to spend time with you getting to the bottom of all this. Though, doctoring can be a toxin in and of itself.
My Dad had dialysis. He died of cardiac arrest during it. It is basically the same as PLEX. Please do realize that it can cause harm for those with heart disease. And it is no easy procedure. In your case, it would probably be best to try in a hospital setting and not a clinic setting. I understand that the "concept" of it is very logical and appealing but the reality of it is far different.
There are also alternative therapies - that have been studied - that can help strengthen (not overexcite) your immune system, like chlorella (sea algae). But, again, you have to look at the impact of all foods and supplements and their possible reactions with drugs.