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Gut microflora is to blame for autoimmune diseases
Last reviewed: 01.07.2025
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American immunologists have come to the conclusion that rheumatoid arthritis may be associated with human intestinal microflora, namely the bacterium Prevotella copri. The researchers made such conclusions after conducting a series of experiments on mice and people susceptible to this disease.
Rheumatoid arthritis is an inflammatory systemic autoimmune disease that affects the connective tissues of mainly small joints and limbs. The joints of the hands, knees, ankles, and ankles are usually affected. What exactly causes the failure of the immune system, after which it begins to actively affect its own tissues, science has not yet figured out.
Immunologist Dan Littman previously conducted research on laboratory mice, as a result of which he established a connection between the composition of the intestinal microflora and the increased activity of T-helpers (specific cells of the immune system), which protect the body from extracellular harmful microorganisms. With the activation of these cells in the body, harmful microorganisms are destroyed. Recently, the scientific community has accumulated a large amount of evidence that T-helpers are key cells in autoimmune diseases. In his research, Dan Littman established that the production of T-helpers in the body depends on the composition of the intestinal microflora in mice. A little later, joint research in this area showed that the activity of these cells increases and ultimately triggers an autoimmune process in which the mouse analogue develops rheumatoid arthritis, filamentous segmented bacteria that are part of the intestinal microflora.
All this data allowed scientists to suspect that the onset of rheumatoid arthritis in humans is also associated with bacteria inhabiting the intestines. A study was conducted on fecal samples from 114 Americans, some of whom had long-term rheumatoid arthritis, while the rest had recently developed the disease. For the researchers, the group with a recent diagnosis was of the greatest importance, since in this case, people had not had time to receive treatment and the composition of their intestinal flora was unchanged.
As a result, the scientists found that in the group with a recent diagnosis, 75% of participants had the gram-negative pathogenic bacterium Prevotella copri (in the group where the duration of the disease was much longer, this bacterium was found in only 37%). The authors have several hypotheses that can explain the connection between the bacterium and rheumatoid arthritis, but they are confident that the onset of the disease involves several environmental factors, and how all these factors combine to trigger the disease process remains to be determined.
This fall, several scientific publications appeared that were devoted to the connection between autoimmune diseases and pathogenic foreign bacteria in the intestine. A team of researchers from New York reported that they had identified the cause of multiple sclerosis, which is the soil bacterium Clostridium perfringens, and researchers from Finland claim that the enteroviruses they identified trigger the development of type 1 diabetes.
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