Welcome back to Season 2 of the Looking at Lyme podcast. Buckle your seatbelts, because we are going on a science adventure with Dr. Theoharis Theoharides, Professor of Immunology at Tufts University School of Medicine in Boston. Dr. Theoharides has been on the leading edge of mast cell research and recounts the fascinating history and physiology of mast cells. Mast cells have existed for over a hundred million years in many different animals and organisms and are found in all body tissues, including the brain. Mast cells are found in worms, fish, lizards; however, these species do not get allergic reactions. So why are mast cells associated with allergic reactions?

Dr. Theoharides explains that mast cells became associated with allergies in 1947 when it was discovered that they contained histamine. He describes the activation of mast cells during anaphylaxis as the sudden release of about 50 molecules from inside these cells, followed by a delayed release 6-12 hours later of further, newly synthesized molecules. He reflects on his earlier research showing that the release of these molecules can also occur, not only with allergies, but also due to many pathogenic, environmental triggers (for example, mold), and stress hormones. He notes that triggers such as Borellia or mold can cause the release of only cytokines (not histamine, or tryptase) from the mast cells. Dr. Theoharides also explains that when mast cells are “primed” with interleuken 33, followed by stress hormone release, the mast cells can release more pro-inflammatory cytokines than any other type of immune cell. This massive release of cytokines is referred to as a “cytokine storm”.

• Read the rest of show notes
• Molecular Immunopharmacology & Drug Discovery Laboratory
• Recent Publications from the Theoharides Lab