Bacteria and Mast Cells: Rethinking Mast Cell Activation

October 29, 2017  |  Histamine Intolerance

The role of bacteria and mast cells is an emerging area of medical research.

Mast cells are best recognized for their role in inflammation, allergies, and lectins, however, the role of bacteria and mast cells are also crucial.

Mast cells play a critical role in the defense against pathogens, bacterial, and viral infections.

This natural role of mast cells seems to have slipped off the radar, in favor of inflammation, and yet the activation of mast cells by infections is well recognized in the scientific literature.

A recent discussion paper co-authored by Theoharides highlights the impact on bacteria and mast cells.

This paper so mirrors my observations that I wanted to highlight these views whilst waiting for the research to catch up.

Mast Cells

Mast cells are part of our immune system.

They act as sentries; stationed predominantly in the skin, the airways, and the intestine, or more importantly where our body meets the environment.

When stimulated, for example by bacteria, mast cells produce a range of mediators, as a helpful protective measure, and at the same time causing wide-ranging symptoms.

Mast cells were perfectly designed to act in this way.

The question, therefore, is not only “how do we suppress the mast cell in acting in this way” but more importantly  “what is the mast cell trying to respond to?”

Mast Cell Activation Syndrome

Mast cell activation syndrome is an acquired condition and very common.

It is typically seen in any label with “syndrome” in its name.

Syndromes are not really “diseases” in which the body’s cells have stopped working, which need to be managed with surgery or drugs. Rather they are a pattern of symptoms as the body adapts to stressors.

Rather than one heterogeneous disease, mast cell activation syndrome can be seen as an umbrella term, with a large variance in mast cell response depending on the trigger.

Any adverse stimulus, such as inflammation, infections, or mold can cause the mast cell to release or even dump immune mediators including histamine. This blog post focuses on bacteria and mast cells.

Life of Mast Cells

Mast cells have a limited life before being replenished. In the same way, we shed skin, we shed mast cells, which are constantly being renewed.

Removal of the trigger, that is stimulating the mast cell, is hypothesized to diminish mast cell activation over time. Speaking personally, this was about a two-year process for me.

Bacteria And Mast Cells

Bacteria can cause mast cell activation by generating toxic compounds or invading the cells.

There is considerable evidence that when endotoxins engage with mast cells they activate them.

Endotoxins are part of the bacteria’s cell wall and are released upon the death of the bacteria. Another term for endotoxins is lipopolysaccharides.

Dysbiosis, such as Small Intestinal Bacterial Overgrowth (SIBO) and bacterial biofilms produce endotoxins.

SIBO, in particular, is highly prevalent, in my experience, with mast-cell activation and addressing dysbiosis can significantly reduce mast cell activation even in the most sensitive of people.

Mast cells may also become hosts to intracellular bacteria that activates the mast cell, alters mast cell behavior, and prevents mast cell death.

Intra-cellular bacteria can be difficult to pick up on standard testing panels as it is not easily found in urine, blood, or stool tests.

An ultrasound is typically used to pick up intra-cellular bacteria although Dr. Klinghardt uses ART ( a medical form of kinesiology) testing.

Bacteria and Mast Cell Stabilizers

The role of bacteria and mast cells can also be linked to beneficial mast cell stabilizers.

The H1 blocker diphenhydramine, commonly known as Benadryl®, has been shown to prevent the increased production of cytokines from mast cells stimulated by bacteria.

Some broad-spectrum antibacterial agents, inhibit mast cell function and degranulation.

Certain strains of probiotics act as mast cell stabilizers especially Lactobacillus Rhammnous GG.

Vitamin D is known to have an immunoregulatory role and to bind with mast cells. It is known that Vitamin D controls nitric oxide, thought to be an anti-bacterial molecule, produced by the mast cells.

These are just some further clues that the role of bacteria and mast cell activation are linked.


Much of the focus within medicine has been on mast cells and their relationship to the mediators they release.

This has lead to much discussion about anti-inflammatory and mast cell stabilizing substances which whilst helpful are little more than a band-aid.

From a functional health perspective, the issue is not whether the mast cell is causing a chemical cascade but what is causing that cascade. This blog post outlines the link between bacteria and mast cells.

In my observation, even in the most sensitive of people, progress can be made through addressing bacterial infections.

Much is still to be learned and it is encouraging to see mainstream medicine’s increasing interest in the link between bacteria and mast cells.

Additional Reading

Conti, Pio, et al. “Link Between Mast Cells and Bacteria: Antimicrobial Defense, Function, and Regulation by Cytokines.” Medical Hypotheses (2017).

Marshall, Jean S. “Mast-cell responses to pathogens.” Nature reviews. Immunology 4.10 (2004): 787.

Zhang, Hanying, et al. “Butyrate suppresses murine mast cell proliferation and cytokine production through inhibiting histone deacetylase.” The Journal of nutritional biochemistry 27 (2016): 299-306.

Matsuguchi, T. “Mast cells as critical effectors of host immune defense against Gram-negative bacteria.” Current medicinal chemistry 19.10 (2012): 1432-1442.

Sandig, Hilary, and Silvia Bulfone-Paus. “TLR signaling in mast cells: common and unique features.” Frontiers in Immunology 3 (2012).

Gutiérrez Venegas, Gloria, et al. “Histamine promotes the expression of receptors TLR2 and TLR4 and amplifies sensitivity to lipopolysaccharide and lipoteichoic acid treatment in human gingival fibroblasts.” Cell biology international 35.10 (2011): 1009-1017.

Talreja, Jaya, et al. “Histamine induces Toll like receptor 2 and 4 expressions in endothelial cells and enhances sensitivity to Gram positive and Gram negative bacterial cell wall components.” Immunology 113.2 (2004): 224-233.

Liu, Z Q., et al. “Vitamin D contributes to mast cell stabilization.” Allergy(2017).

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