Editing Leslie's "Mast cells show their might" 2010 (section)

==The bad==
*It seems that mast cells may be a factor causing rheumatoid arthritis because mice without mast cells don't develop the condition and mast cells have been shown to release IL1 which attracts inflammation-inducing cells to the joints.
*It has been shown that MS symptoms set in later in mice that don't have mast cells (and not just a lack of CNS mast cells).
*It seems that mast cells (which have been shown to inhabit plaque in the arteries) may help to loosen it up, thus causing heart attacks.
**Indeed, in mice strains that are prone to atherosclerosis, when mast cells are removed, the plaques are smaller and less likely to fracture.  Researchers think this has to do with mast cells' ability to stimulate local cells to release cathepsins which cause problems.
*Even more, mice with mast cells were more likely to go into ventricular tachycardia (a deadly fibrillation that often occurs once blood flow is returned to the heart) than mice that had to mast cells.