A team from several research institutions led by Dr. Anneli Peters (LMU Biomedical Center) and Professor Hartmut Wekerle (Max Planck Institute for Biological Intelligence), including our member Lisa Ann Gerdes, launched a major collaborative project—with the help of twins. Although identical twins share nearly the same genetic makeup, in some MS cases one twin may develop the disease while the other remains symptom-free—known as an MS-discordant pair. A summary of their study: 

• Multiple sclerosis (MS) and the gut flora: MS is the most common inflammatory disease of the central nervous system. Among many other factors, microorganisms in the gut are suspected of contributing to the onset of the disease.
  
• Twin study: To obtain meaningful results, researchers* examined stool samples and microorganisms directly from the small intestine of identical twins, where only one twin had MS.
  
• Disease-causing bacteria: Using a transgenic mouse model of the disease, they identified Lachnoclostridium and Eisenbergiella tayi for the first time as potential disease-causing bacteria in the intestinal samples of twins with MS.
  
• Successful experimental strategy: The study demonstrates ways to identify disease-causing bacteria and could eventually result in new therapeutic approaches for humans.
  

H. Yoon, L. A. Gerdes, F. Beigel, Y. Sun, J. Kövilein, J. Wang, T. Kuhlmann, A. Flierl-Hecht, D. Haller, R. Hohlfeld, S. E. Baranzini, H. Wekerle, A. Peters: Multiple sclerosis and gut microbiota: Lachnospiraceae from the ileum of MS twins trigger MS-like disease in germfree transgenic mice—An unbiased functional study. PNAS 2025