The well-established involvement of B cells in NMO pathogenesis, via IL-6 and AQP4-ab production, highlights the rationale for anti-CD20 and anti-CD19 therapies, whose efficacy has been demonstrated in various clinical trials (Cree et al., 2019; Tahara et al., 2020). The gene discussed is AQP4; the disease is neuromyelitis optica.