CD40LG and myelitis: We identified isolated MOG-IgA in a small subset of patients presenting with myelitis, brainstem syndrome, and infrequent optic neuritis overlapping with core clinical features of NMOSD7 and MOG antibody–associated disease.8 While the coexistence of MOG-IgM and MOG-IgA has previously been described12 in a similar frequency as detected in our cohort, we expand on the existing literature by reporting isolated MOG-IgA seropositivity in patients seronegative for MOG-IgG/-IgM and AQP4-IgG.