Can you have an auto immune disease with no symptoms?

Qualified yes: There can be laboratory evidence of an autoimmune process in the absence of symptoms/disease. An example of this is low levels of ANA with no clinical signs of Lupus. It can be a matter of degree or exceeding a symptom threshold.

Dr Chiu agreed

Yes: Many diseases do not show any symptoms until the very late stage. For example, one does not have a heart attack because the coronary artery suddenly jam up one day. The same is true with chronic smoking, the lung is being damaged but symptoms may not show some years later. This is the same with autoimmune disease.

Dr Gabor and another doctor agreed