I do have both MS and AS. I was dx with MS in 1998 and was on biologic grugs for 13 years. 2017, dx with AS, due to HLA-B27. My grandson has Uveitis and my daughter thought there might be a genetic link because she was having back problems. All 3 of us have that gene.
I had to go off the MS drugs because of skin cancer. Switched to Paleo diet (Autoimmune Protocol) and have been on it since. In 2017 the Rheumatologist looked at the HLA-B27 and recommended Cosentyx. Without the rest of the info like MRI and such, insurance denied, so we decided to ignore. I think I've been dealing with more AS pain than I figured. I have lots of spasticity with the MS, so my Neurologist and I have been dealing with my pain through that route, probably hiding some of the cause.
I decided to go to a Rheumatologist because of sciatic pain and he discovered that I def have AS and thorasic spine1-10 is fused. He took part in a study that proved that people with MS get lots worse on TNF biologics. I am now on Cosentyx. It is starting to make a difference in my pain levels. I still walk. I exercise a lot. Still have trouble with sleep due to pain, but I'm hoping that improves. I work out with other women 60 & older who have MS on ZOOM using the MS Gym format. For me, exercising really stops the pain.
When I stopped the biologics for MS, Dr Whal's Protocol came out for people with MS. She said "If you can do nothing else for MS, stop gluten." I haven't had gluten since 2011. It took 3 months, but after that my fatigue lessened by a large amount. In 2017 when I found out I had AS, I ran into a website, called "Ralphitness", which is now offline, but it taught me a lot about pain management and self-esteem in managing AS. Between exercise and diet and managing self-esteem issues, I think AS and MS are managable. Altho, after a pain filled night, I sometimes doubt it.