@rgg- There are a lo to of lapses in information for COVID-19 and immunology. There just hasn't been time for every illness to have been tested. But thank goodness these vaccine have come along at all!

I know that it is very frustrating and scary not to have data about the vaccines and how they apply to our specific situation. The experts advise that anyone with a suppressed immune disease should have the vaccines. They will give added protection even if it's not ideal.
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-should-you-get-vaccinations-with-a-suppressed-immune-system/
https://www.uchicagomedicine.org/forefront/coronavirus-disease-covid-19/immunocompromised-patients-covid-19-vaccines
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/underlying-conditions.html
Each of the above sites explains a different look at your question. Please remember that only a few exceptions are made with the vaccines and immunology issues. The main point is with a suppressed immune system you are MORE susceptible to CPVID-19. If your doctor encourages you to have the vaccine then you should have it.

There are hundreds and hundreds of autoimmune diseases. And it can be very difficult to decide to have the vaccine. I know that people who have autoimmune diseases can't have certain vaccines because they have live viruses. But Both the Pfizer and Moderna vaccines do not have live viruses.

"COVID-19 vaccines help our bodies develop immunity to the virus that causes COVID-19 without us having to get the illness." CDC

Does this all make sense?