A new study published in the Journal of Allergy and Clinical Immunology: Global suggests that people with systemic mastocytosis (SM) have measurable changes in their gut microbiome that may influence symptoms, inflammation and mast cell activationMast cell activation Describes when mast cells release histamine and other mediators into the blood stream in response to an allergen or other trigger. This leads to symptoms like fatigue, rash and, in severe cases, anaphylaxis..
The gut microbiome helps regulate many body processes, including inflammation and immune responses. When the microbiome becomes unbalanced, it can affect how the immune system behaves. In SM, where mast cells are already overactive, that imbalance could potentially make symptoms worse.
For the study, researchers at the National Institutes of Health analyzed stool samples from 22 individuals with indolent SMIndolent SM A subtype of nonadvanced SM caused by the abnormal accumulation of mast cells in the bone marrow and other organs. Indolent SM accounts for around 90% of SM cases. and 10 healthy controls. They found that those with SM showed a distinct microbial profile compared with healthy participants. Specifically, the researchers observed shifts in two major bacterial groups: Firmicutes and Bacteroidetes. People with SM had an altered Firmicutes composition and an increased abundance of Bacteroidetes compared to the healthy volunteers.
These bacterial changes, known as dysbiosis, were linked to measures of disease activity, including serum tryptaseTryptase A protein enzyme that is primarily produced by mast cells and stored in small pockets within the cells, known as granules. High levels of tryptase are a key indicator of SM. levels and the frequency of the KIT D816V mutation, both of which are indicators of mast cellMast cell A type of white blood cell produced in the bone marrow. They help defend against infections and play a key role in allergic reactions. In SM, mast cells become overactive and build up throughout the body. burden and activation.
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Diet appeared to play a significant role, as well. Participants’ intake of animal versus vegetable protein, fiber and fat correlated with both microbiome composition and symptom severity. For example, those who consumed lower amounts of fiber experienced more abdominal pain and nausea. Higher fat intake was associated with increased tryptase levels. These findings suggest that diet may modulate both the gut microbiome and disease manifestations in SM.
While the study was small and exploratory, it adds to growing evidence that the gut microbiome and diet may influence mast cell activity and overall symptom patterns in mast cell disorders. The authors noted that further research could help clarify whether targeted dietary strategies or microbiome-based therapies, such as probiotics, could improve quality of life or reduce inflammation in people with SM.
“Further investigation with a larger sample size to enable consideration of management of disease and other manifestations and variants of SM will be useful to elucidate the clinical significance of these findings,” the study’s authors concluded.
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