C. bolteae is elevated in NMOSD in India and shares sequence similarity with AQP4

Objective: To understand the role of gut microbiome in influencing the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD) among patients of south Indian origin.Methods: In this case control study, stool and blood samples were collected from 39 NMOSD patients, including 17 with aquaporin 4 IgG antibodies (AQP4+) and 36 matched controls. 16S rRNA sequencing was used to investigate the gut microbiome. Peripheral CD4+ T cells were sorted in 12 healthy controls & 12 AQP4+ NMOSD patients, RNA extracted, and immune gene expression analyzed using Nanostring nCounter human immunology kit code set.Results: Microbiota community structure (beta-diversity) differed between AQP4+ NMOSD and healthy controls (p Conclusion: Our study described elevated levels of C. bolteae associated with AQP4+ NMOSD among Indian patients. It is possible that this organism may be causally related to the immunopathogenesis of this disease in susceptible individuals.