I have this same thing. And I've been in diagnostic testing since 2018. Mid 2019 showed the elevated levels. And then muscle biopsy done early 2020 showed nothing as expected. I was referred to another neurology clinic for a 2nd opinion. Which I've seen them since early March this year and they are admitting into the hospital for a 5 day stay to receive ivig therapy to help with my symptoms. And I'm so nervous. As you said, there's not much known yet about this. And for me in particular. They've already long ruled out just about every single other diagnosis it could be/that causes sfn. I hope theres more to read in these comments! And I'll share my experience as i go through it!

I had 5 dose IvIg in July for TsHDS and another two dose this month. I was struggling with two much headaches after that. If I compare before and after IVIG, I have been very slightly better, I do not know yet if it will work. I have had burnning in feet and diziness and balance issues, I feel kind of unsteady all the time, I am very interested to know if you have taken IvIg and what are your symptoms and did that help? Thanks.

I also have high TS-HDS antibodies and small fiber neuropathy. I was treated with Solumedrol infusions and my level came down. It is back up again after close to two years. I have moderate to severe pain. I have tried various treatments for pain but they tend to become ineffective over time. I would be interested in finding out more about people with similar issues and how they are addressing the diagnosis. How do I join the Facebook group mentioned in an earlier post?