Inclusion Criteria:  Female aged 18-55, inclusive at the time of consent Not pregnant at the time of the screening/baseline visit Able to understand the purpose, benefits, and risks of the study; willing and able to adhere to the study requirements; able and provide informed consent in English  Meet the criteria of one of the four groups at the time of consent:  Group 1: subjects who have recently been diagnosed with MS, have had a clinical attack within the last 6 months, have not received steroids in the last 30 days, and have not started on a disease modifying therapy Group 2: subjects with clinically stable relapsing MS, with no evidence of clinical relapse for at least the past 12 weeks, and have no gadolinium enhancing lesions on MRI in the prior 4 weeks, who are receiving a FDA-approved MS DMT Group 3: subjects with relapsing MS on a FDA-approved DMT but with evidence of breakthrough disease, with a documented clinical relapse and/or gadolinium-enhancing lesion(s) on brain or spinal cord MRI taken within the 4 weeks Group 4: subjects without evidence of inflammatory systemic or CNS disease, who require CSF removal for some other cause, such as for idiopathic intracranial hypertension or communicating hydrocephalus  Exclusion Criteria:  There are no exclusion criteria for this study.