Demyelinating disease that primarily affects the spinal cord and optic nerve, neuromyelitis optica spectrum disorder (NMOSD) is very uncommon. Clinical and laboratory tests have not been able to reliably predict the course of the illness, the extent of any resulting impairment, or the likelihood of a recurrence. Interleukin 6 (IL-6) is a proinflammatory cytokine that is seen at increased levels in the serum and CSF of NMOSD patients. The purpose of the research was to see whether IL-6 levels in the serum might be used as a biomarker for NMOSD disease activity. Researchers examined the blood levels of IL-6 in 26 NMOSD patients at different illness pivot points, using enzyme-linked immunosorbent assay (ELISA). Using the volBrain program, they connected serum IL-6 levels with measurements of brain MRI volume, the Expanded Disability Status Scale (EDSS), therapies for preventing neuromyelitis optica (NMO), and clinical subtypes (relapse and remission states). Relapsed NMOSD patients reported greater IL-6 levels compared to those in remission. No variations in the blood levels of IL-6 was identified between NMOSD patients at remission and HCs. Total protein in the CSF is favorably correlated with IL-6 levels during relapse. In addition, there is an inverse relationship between IL-6 levels at relapse and the sizes of the brain’s various regions, including the cerebellum, brain stem, thalamus, and putamen. Based on the results, IL-6 levels in the blood might be used as a biomarker for illness progression (e.g., relapse vs. remission). Considering that elevated IL-6 levels are associated with decreased brain volume, the IL-6 signaling pathway may mediate impairment.