Tag: immune system

Categories : Immune SystemTags :

Gut Microbiota Have Large Effects on Immune System

On By ModernMedia

For the first time, immune cells in the bloodstream have been shown to be affected by the makeup of gut microbiota.

In recent years, there has been increased interest in gut microorganisms and their influence on human health, partly as a result of improvements in the ability to study them. Much prior understanding of gut microbiota on the immune system comes from animal studies; this study was able to examine the effects in humans. This study used data from allogeneic stem cell and bone marrow transplants (BMTs), where the patient’s blood formation system is destroyed by radiation or chemotherapy and replaced with stem cells from a donor’s bone marrow. The patient is given antibiotics until the transplanted cells are able to re-establish the immune system, the gut microbiota being destroyed in the process and then re-establishing once the antibiotics are withdrawn. Over a period of ten years, a multidisciplinary team with the Memorial Sloan Kettering Cancer Center took blood and faecal samples from BMT patients.

Study author Dr Joao Xavier said, “Our study shows that we can learn a lot from stool—biological samples that literally would be flushed down the toilet. The result of collecting them is that we have a unique dataset with thousands of datapoints that we can use to ask questions about the dynamics of this relationship.”
“The parallel recoveries of the immune system and the microbiota, both of which are damaged and then restored, gives us a unique opportunity to analyse the associations between these two systems,” lead author Dr Jonas Schluter said.

A higher diversity of microbiota was shown to lower the risk of death following a BMT, and a lower diversity increased the risk of graft-versus-host disease, a potentially fatal condition where the transplanted marrow attacks the host’s body.

“Because experiments with people are often impossible, we are left with what we can observe,” Dr. Schluter noted. “But because we have so many data collected over a period of time when the immune system of patients as well as the microbiome shift dramatically, we can start to see patterns. This gives us a good start toward understanding the forces that the microbiota exerts on the rebuilding of the immune system.”

Source: Medical Xpress

Journal information: Jonas Schluter et al. The gut microbiota is associated with immune cell dynamics in humans, Nature (2020). DOI: 10.1038/s41586-020-2971-8

Categories : Gastrointestinal Neurodegenerative DiseasesTags :

Gut Immune Cells Protect The Brain in MS Flare-ups

On By ModernMedia

Scientists from the University of California, San Francisco, have observed gut immune cells moving up out of the gastrointestinal tract to the brain during multiple sclerosis (MS) flareups, where they seem to exert some protective effects.

In MS, other immune cells attack the myelin sheath, resulting in flare-ups, where they experience memory problems, vision loss, pain and other problems. These flare-ups subside after some days, but it is not known why the disease switches back and forth between flare-up and remission.

The new research revealed that the flare-ups were brought under control with the unlikely assistance of gut immune cells, which produce Immunoglobulin-A (IgA) and act as the immune system’s first line of defence in the GI tract. Some of these cells actually leave the gut and migrate to the brain, where it appears they reduce inflammation.

“It was a very new idea,” said lead author, Sergio Baranzini, PhD, neurology professor at the UCSF Weill Institute for Neurosciences, . “Nobody thought to look for this type of immune cell.”

The gut immune cells were found only in cerebrospinal fluid of MS sufferers when they experienced a flare-up, and not in remission. Recent research indicated that an unhealthy GI microbiome was involved in MS, and the researchers determined that these immune cells only attacked potentially damaging bacteria, not the myelin sheath.

It is anticipated that this discovery may bring insights into new therapies to treat the disease. 

Source: Medical Xpress