Gut microbiota dysbiosis characterized by abnormal elevation of <i>Lactobacillus</i> in patients with immune-mediated necrotizing myopathyOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study asked whether gut bacteria are altered in immune-mediated necrotizing myopathy (IMNM), a rare autoimmune muscle disease. Researchers profiled fecal microbiota using 16S rRNA gene sequencing of the V3-V4 region. They compared bacterial diversity and composition between patients and healthy controls. They also correlated bacteria with clinical and laboratory measures. Alpha diversity, beta diversity, Welch's t test, LEfSe, and Spearman correlation were applied. A ROC curve tested whether top genera could predict disease.
Who was studied?
The cohort was 19 IMNM patients and 23 age- and sex-matched healthy controls at West China Hospital, Sichuan University, enrolled 2020 to 2022. Mean age was about 56 years in patients and 50 in controls. Most patients were on glucocorticoids (18 of 19) and many on disease-modifying antirheumatic drugs (11 of 19). Disease activity was scored by MITAX and MYOACT. Controls were family members without muscle disease. Recent antibiotic, antiviral, or antifungal users were excluded.
What were the most important findings?
Patients showed lower gut diversity than controls, with significant drops in Shannon, Simpson, and Chao1 indices (p less than 0.05). Community structure also separated the two groups (ANOSIM R equals 0.288, p equals 0.001). The phylum Bacteroidota fell in patients (p equals 0.003). At genus level, Bacteroides, Roseburia, and Coprococcus were reduced, while Lactobacillus and Streptococcus rose. Lactobacillus tracked anti-SRP and anti-Ro52 antibodies and ESR. Roseburia was inversely linked to myoglobin, troponin T, and interstitial lung disease. A five-genus model reached an AUC of 87 percent.
What are the greatest implications of this study?
The results suggest gut dysbiosis accompanies IMNM and tracks with autoimmune and muscle-injury markers. Elevated Lactobacillus and depleted butyrate-linked genera may reflect disease-associated shifts. These associations are correlational, so the study cannot show that bacteria cause muscle damage. Most patients were already on immunosuppressants, which may shape the microbiota. Still, the findings point to microbial genera as candidate biomarkers and possible future targets worth testing in larger, treatment-naive cohorts.