I find the best articles under the clinical research:

Annals of the New York Academy of Sciences
© The New York Academy of Sciences, June 2008,
Volume 1132 Myasthenia Gravis and Related Disorders 11th International Conference
Pages 84-92 ,Myasthenia Gravis Seronegative for Acetylcholine Receptor Antibodies

There was a great article where they tested sseronegative ACHR and MUSK MGers by adding Rapsyn ( the thing that makes ACHR receptors cluster) and 60% of the seronegative showed low affinity binding for ACHR antibodies. That means seronegative fit the clinical profile for ACHR Mgers. The test is faulty or not sensitive enough and does not taken into account the heavy clustering of ACHR receptors in the body.

Rapsyn is under investigation as a future treatment for MG. If the ACHR receptors cluster more it is easier to get a muscle action potential and our muscles will work better. At least that is the theory.

I also found another interesting article, I can't find the link now. But it did not consider ACHR antibody a definitive test for MG. It considered, SFEMG, tensilon etc, the definitive test. It said that the antibody tests should be used to profile and subtype the MG to anticipate clinical presentation and treatment response. I think this is a great approach. I wish more neuros used it.

Hope this helps,
kathie