Biomarkers in Autoimmune Disease of Nervous System

This study is collecting blood and biological samples from people with autoimmune diseases of the nervous system to identify biomarkers that could help with earlier diagnosis and better understanding of these conditions. Healthy volunteers are also needed for comparison. **You may be eligible if...** - You have been diagnosed with one of the following autoimmune neurological conditions: neuromyelitis optica spectrum disorder (NMOSD), myasthenia gravis, CIDP, inflammatory muscle disease, multiple sclerosis, autoimmune encephalitis, MOGAD, or similar conditions - You are a healthy individual matched for age and sex (for the control group) **You may NOT be eligible if...** - You have a known primary immune deficiency - You have a severe brain, lung, or systemic infection - Your neurological symptoms are caused by a secondary condition such as lupus or vasculitis - You have a blood vessel disease, hereditary metabolic condition, brain tumor, or toxic cause for your neurological symptoms - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.