AQP4 and myeloid sarcoma: Vascular risk factors have a known detrimental effect in inflammatory diseases of the central nervous system (CNS) such as MS, with smoking in particular being associated with greater disability and a higher burden of MRI lesions.6, –8 In NMOSD, previous studies reported that smoking affects the severity of the disease9 and may be associated with poor relapse recovery in NMOSD-AQP4.10 However, the impact of smoking on MRI lesion resolution, and the role of MRI as a surrogate for clinical improvement, has not been studied before.