Myasthenia gravis gut fungi

Abstract: An altered gut microbiota is a possible contributing pathogenic factor in myasthenia gravis (MG), an autoimmune neuromuscular disease. However, the significance of the fungal microbiome is an understudied and neglected part of the intestinal microbiome in MG. We performed a sub-analysis of the MYBIOM study including faecal samples from patients with MG (n = 41), non-inflammatory neurological disorder (NIND, n = 18), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP, n = 6) and healthy volunteers (n = 12) by sequencing the Internal Transcribed Spacer 2 (ITS2). Fungal reads were obtained in 51 out of 77 samples. No differences were found in alpha-diversity indices computed between the MG, NIND, CIDP, and HV groups, indicating an unaltered fungal diversity and structure. Overall, five mould species (Penicillium aurantiogriseum, P. spinulosum, Cladosporium herbarum, C. ramotenellum and Septoglomus deserticola) and four yeast species (Candida albicans, C. sake, C. dubliniensis and Pichia mandshurica) were identified. Hpwever, besides one MG patient with abundant Candida albicans, no prominent dysbiosis in the MG group of the mycobiome was found. Not all fungal sequences within all groups were successfully assigned so that further sub-analysis was withdrawn, limiting robust conclusions. Keywords: Myasthenia gravis, chronic inflammatory demyelinating polyradiculoneuropathy, ITS2, mycobiome