I have a compromised/suppressed immune system myself, and I've never been on any immunosuppressants either. What I know is that most of the major health issues I've dealt with (except PN) began with two things: extreme stress and viruses (either alone or re-activating earlier viruses) - Mononucleosis (Epstein-Barr), Crohn's/IBS (virus cold), chronic headache complex (virus cold reactivated Epstein-Barr). Some viruses can stick around for your lifetime, rearing their ugly heads and raising cuss in times of stress (and others) and weakening the immune system.

I have to eat nutritiously, get sufficient rest/sleep, keep a lid on stress, and otherwise keep an eye on my immune system and try to keep it as healthy as I can.

I'm not suggesting viruses are your cause - that would take some significant detective work.

Doc