Intestinal Immunity in Neurologic Disease

This study is investigating how the immune system in the gut may be connected to neurological and autoimmune diseases. Researchers will collect small tissue samples (biopsies) during a routine or research colonoscopy and/or upper endoscopy to study immune cells in the intestines. Understanding this connection could help develop better treatments for conditions affecting the nervous system. **You may be eligible if:** - You are 18 years or older - You are already scheduled for a routine screening colonoscopy (with or without upper endoscopy), whether you are healthy or have a neurological or autoimmune disease, OR you are willing to have a colonoscopy for research purposes **You may NOT be eligible if:** - You are currently pregnant - You have a known chronic inflammatory gut disease (such as Crohn's disease or ulcerative colitis) - You have a current acute or chronic infection - You took oral or IV antibiotics within the past 3 months - You took corticosteroids (such as prednisone 10 mg/day or more for more than 5 days) within the past 2 weeks - You have been diagnosed with or treated for cancer in the last 5 years - You took probiotics in the past 2 weeks - You have had major gut surgery (such as colon removal or gastric bypass) - You have a bleeding disorder or take blood thinners - You are allergic to anesthesia medications used during the procedure Talk to your doctor to see if this trial is right for you.