PURPOSE OF REVIEW: This review summarizes recent insights into the pathogenesis 
and therapeutic options for patients with MOG- or AQP4-antibodies.
RECENT FINDINGS: Although AQP4-IgG are linked to NMOSD, MOG-IgG-associated 
diseases (MOGAD) include a broader clinical spectrum of autoimmune diseases of 
the central nervous system (CNS). Details of membrane assembly of AQP4-IgG 
required for complement activation have been uncovered. Affinity-purified 
MOG-IgG from patients were shown to be pathogenic by induction of demyelination 
when the blood--brain barrier (BBB) was breached and by enhancement of 
activation of cognate T cells. A high-affinity AQP4-IgG, given peripherally, 
could induce NMOSD-like lesions in rats in the absence of BBB breach. 
Circulating AQP4-specific and MOG-specific B cells were identified and suggest 
differences in origin of MOG-antibodies or AQP4-antibodies. Patients with 
MOG-IgG show a dichotomy concerning circulating MOG-specific B cells; whether 
this is related to differences in clinical response of anti-CD20 therapy remains 
to be analyzed. Clinical trials of AQP4-IgG-positive NMOSD patients showed 
success with eculizumab (preventing cleavage of complement factor C5, thereby 
blocking formation of chemotactic C5a and membrane attack complex C9neo), 
inebilizumab (depleting CD19 + B cells), and satralizumab (anti-IL-6R blocking 
IL-6 actions).
SUMMARY: New insights into pathological mechanisms and therapeutic responses 
argue to consider NMOSD with AQP4-IgG and MOGAD as separate disease entities.