Does the Gut Microbiota Influence Autoimmune Diseases?

The gut microbiota plays a key role in the development and regulation of the immune system. When an imbalance occurs in this microbial community, known as dysbiosis, it can disrupt the intestinal barrier and trigger excessive inflammatory reactions. This promotes the onset of autoimmune diseases such as type 1 diabetes, rheumatoid arthritis, or multiple sclerosis. In individuals with these conditions, there is often a decrease in anti-inflammatory bacteria, such as Faecalibacterium prausnitzii, and an increase in pro-inflammatory bacteria, such as Prevotella copri.

The microbiota produces components like lipopolysaccharides, which are present in the bacterial cell wall. In excess, these damage the intestinal mucosa and increase its permeability, a phenomenon sometimes referred to as “leaky gut.” This allows harmful substances to cross the intestinal barrier and inappropriately activate the immune system, thereby contributing to chronic inflammation and the loss of immune tolerance.

Probiotics, which are beneficial live microorganisms, could help restore the balance of the microbiota. They act by reducing the translocation of lipopolysaccharides into the blood, enhancing the production of short-chain fatty acids, and supporting the regulatory cells of the immune system. Short-chain fatty acids, such as butyrate, have anti-inflammatory properties and help maintain the integrity of the intestinal barrier. They also promote the function of regulatory T cells, which limit excessive immune responses.

Studies show that probiotics can alleviate symptoms of certain autoimmune diseases. For example, in patients with rheumatoid arthritis, an eight-week supplementation with Lactobacillus casei reduced inflammatory markers such as C-reactive protein. In the case of multiple sclerosis, certain probiotic strains, such as Prevotella histicola, have demonstrated their ability to modulate the immune response by inhibiting the activation of Th1 and Th17 lymphocytes, which are involved in the progression of the disease.

For type 1 diabetes, trials on animal models have revealed that early administration of probiotics can reduce the incidence of the disease by modulating the immune response and improving the function of pancreatic beta cells. In humans, probiotic supplementation from the first month of life appears to decrease the risk of developing autoimmunity against insulin-producing cells.

However, the effectiveness of probiotics varies from individual to individual. Their action depends on the initial composition of the microbiota and the specific profile of the disease. Additionally, study results remain limited by small sample sizes and short observation periods. The immunological mechanisms involved are not yet fully understood, and the long-term effects of these treatments remain unknown.

Another therapeutic approach being explored is fecal transplantation, which involves transferring the microbiota from a healthy donor to a patient. This method has shown encouraging results in some cases of rheumatoid arthritis and multiple sclerosis by restoring microbial diversity and reducing inflammatory symptoms. However, its use remains experimental and requires further studies to assess its safety and long-term effectiveness.

The gut microbiota also communicates with the brain via the gut-brain axis, a bidirectional signaling network. Disruptions in this axis could contribute to neuropsychological disorders, such as depression or neurodegenerative diseases. In multiple sclerosis, for example, an alteration of the microbiota can worsen inflammation of the central nervous system by promoting the activation of immune cells.

Despite these advances, microbiota-based treatments should not yet be considered standalone solutions. They could rather complement existing therapies as part of a comprehensive approach. Probiotics and fecal transplantation offer promising avenues, but their use requires rigorous case-by-case evaluation, taking into account the specificities of each patient.

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Study Citation

DOI: https://doi.org/10.1007/s00284-026-04992-1

Title: Gut Microbiota and Autoimmune Diseases: The Therapeutic Potential of Probiotics

Journal: Current Microbiology

Publisher: Springer Science and Business Media LLC

Authors: Angelika Domagała; Aneta Kiecka