One was an adult patient with left optic neuritis and was treated with steroids (initially low-dose oral steroids, then high-dose intravenous steroids followed by oral steroid taper) starting 20–30 days prior to MOG-IgG collection and the other was a pediatric patient with ADEM who received a course of high-dose intravenous steroids followed by short oral steroid taper starting three weeks prior to MOG-IgG collection. The gene discussed is MOG; the disease is acute disseminated encephalomyelitis.