Immunoglobulin Deficiency a Treatable Cause of Fatigue in Patients With Multiple Sclerosis (MS)?

This study is investigating whether low antibody levels (immunoglobulin deficiency) in people with multiple sclerosis (MS) may be causing fatigue, and whether treating this deficiency might help. **You may be eligible if...** - You have been diagnosed with multiple sclerosis (MS) according to standard 2017 criteria - You are between 18 and 65 years old - Your MS has been stable for the past 12 months (no relapses, no new brain lesions, no worsening disability) - You have been on the same MS treatment for at least 12 months - You are still able to walk without major disability **You may NOT be eligible if...** - You have severe depression - Your MS has been active or changing recently - You have changed MS treatments in the past year - You have significant walking disability Talk to your doctor to see if this trial is right for you.