[AnnieB3]

You wrote this in Abby's thread.

Hi Annie,

A basic question:
I used to have this all the time. Does that mean that those with negative blood tests have different antibodies that don´t respond to the standard blood tests? Or is their ´transferrable´weakness caused by some other type of process?

Abby is trying to work some things out, so I thought I'd start a new thread for your question.

Antibodies can circulate in the blood or they can be "tissue bound." It's possible that, in some cases, not enough antibodies circulate in the blood to show up on a blood test. And sometimes antibodies don't show up until later on in the disease process. Or an MGer is so mild that their "attack" isn't as bad as others (yet).

Researchers are looking at multiple antibody possibilities in MG, as well as a channelopathy (as in Abby's post) as a cause of MG. There's LRP4, a new MG antibody which Brian brought up awhile ago. Titin. Ryanodine. The list of possible antibodies is long because there are a lot of places in the neuromuscular junction that antibodies - begun by proteins - could attack.

Part of the issue about one part of the body becoming weak when it's not being used is that you can't separate parts of our bodies! Think about what muscles you use when you sit. Well, if you didn't use any, you'd fall over like a rag doll! Which is what happens in an MG crisis. We use a LOT of our muscles while sitting. Our "core" muscles especially, which can make us short of breath if we overuse them.

If anyone else can answer this better, please chime in! I'm not too awake yet today.

I didn't realize all of the muscles I used while laughing. Years ago, I spent a really fun time with family members who were in town for a visit. My neck cramped up after minutes of socializing. I was short of breath and overall weak for two weeks. I slept with my mouth open for a few days due to jaw/tongue weakness. Yes, muscles not only open things up but close them too!

Does this help answer your question? Do you have more? Don't be shy about asking what you need to know. MG is such an odd little disease. You can feel like you have a handle on it and then it'll just surprise the heck out of you.

Annie