(Vienna, 14 February 2025) A recent study involving the Medical University of Vienna in an international collaboration provides new insights into bacterial vaginosis, the most common infection of the female genital tract caused by bacteria. This disease is associated with an increased risk of sexually transmitted infections, HIV and premature births. The results of the study published in the journal Scientific Reports could open up new therapeutic approaches.
The researchers led by first author Philipp Fößleitner from the Department of Obstetrics and Gynecology at MedUni Vienna, who was a Postdoctoral Research Fellow in Caroline M. Mitchell's research group at the Vincent Center for Reproductive Biology at Massachusetts General Hospital (MGH), Harvard Medical School, investigated how changes in the vaginal microflora affect the immune system. Samples from 20 women with bacterial vaginosis were analysed before, during and after treatment with the antibiotic metronidazole. The results show that a change in the microbial balance is associated to specific immune responses: a decrease in monocytes (a type of immune cell) indicated an improvement, while an increase in these cells and dendritic cells was associated with a worsening of bacterial vaginosis. This suggests that antigen-presenting cells such as monocytes play a crucial role in the immune response to this vaginal infection.
The researchers also discovered that an improvement in the infection was associated with an increased number of B cells and an increase in certain immune response-mediating messenger substances (IP-10, MIG and ITAC). IP-10 in particular could play a central role in the reestablishment of a healthy vaginal flora.
The results of this study are consistent with previous studies that showed a decrease in monocytes in women whose bacterial vaginosis was successfully treated. The researchers hypothesise that changes in the immune response could influence both the bacterial composition of the vaginal flora and the risk of infection. However, further studies are still needed to better understand the long-term effects of these immune changes on the risk of infection and the course of the disease.
These new findings could help to develop more targeted treatments for bacterial vaginosis and reduce the potential health risks for affected women.
Publication: Scientific Reports
Association between changes in genital immune markers and vaginal microbiome transitions in bacterial vaginosis
Philipp Foessleitner, Briah Cooley Demidkina, Wafae El-Arar, Miles Goldenberg, Meena Murthy, Agnes Bergerat, Ofri Bar, Douglas S. Kwon & Caroline M. Mitchell
https://doi.org/10.1038/s41598-025-88208-9