Well, in digging into some research papers, I found "mast cell activation can be caused by both IgE-mediated and non–IgE-mediated triggers".

This is because there can be a mast cell mutation (KIT) which then doesn't require IgE for activation. You have MMAS and not Mastocytosis, right? The mutation seems to be associated with Mastocytosis based on my understanding from the paper.

Since mast cells aren't privileged, they're restricted from entering sites like the brain and spinal cord. So, if they're in the spinal cord, you almost certainly have bigger problems than mast cell activation I'd think, as the barrier isn't doing it's job.

In case you're interested, here's the paper on mast cell disorders: https://www.jacionline.org/article/S0091-6749(17)31025-4/fulltext

Here's one on the brain and spinal cord: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481533/

The BIGGEST issue with our understanding of the immune system today is that ALL testing is done on mice. The human body on a chip technology along with the digitization of the immune system together will be a monumental step. Thankfully, it's literally something we'll have in the near future. Once that's available, we'll have human specific data plus an onslaught of constant information, which we need to help folks with all of the immune system disorders. I'm an autoimmune patient and losing my friends and family to this uncertainty has led me into the field to try and help improve our understanding. There's legit more we don't know than we do know about the human immune system right now.