This is a study during which the investigators collect plasma and cells from patients with myasthenia gravis for the purpose of finding new antibodies.

This is a bio-specimen collection study. The investigators will collect plasma and peripheral lymphocytes. Plasma will be collected either when the patient undergoes plasma exchange, a decision independent of this study, or through a scheduled blood draw.

Patient plasma will be screened for novel antibodies which may cause myasthenia gravis. Subjects that are found to be positive for candidate antigens for myasthenia gravis will have a clinical evaluation which will consist of several disease rating scales will be performed (QMG score, MG-composite, Myasthenia Gravis Foundation of America (MGFA) clinical classification, MG-Quality of Life (QOL)15, MGFA Therapy Status).

Inclusion Criteria:

• 18 years of age or older.
• Clinical Diagnosis of MG with supporting evidence either from antibody testing, repetitive nerve stimulations study (RNS) or Single Fiber Electromyography (EMG) (SFEMG).

Exclusion Criteria:

• Significant medical condition that would make participation in diagnostic and research part of evaluation impossible or risky. Acute or unstable medical condition.
• Inability to provide informed consent, either directly or via appointed power of attorney.
• Unwillingness to consent for collection of biological samples or their cryopreservation.
• Unable to provide evidence of previous antibody testing or neurophysiology confirming the diagnosis of Myasthenia Gravis.
• Any bleeding disorder that would prevent or present any danger during blood extraction.

Patients with Myasthenia Gravis and normal controls