In autoimmune disease, the immune system produces antibodies that target the body's own molecules and tissues.

This study found that people with autoimmune diseases often have antibodies that attack parts of our own DNA that came from ancient viruses—kind of like the body mistakenly fighting its own hidden viral leftovers. This supports the idea that autoimmune diseases happen when the immune system wrongly targets the body’s own stuff.

This study found that people with a kidney disease called IgA nephropathy make antibodies that mistakenly attack their own kidney cells — which is exactly what autoimmune diseases do: the body attacks itself. So yes, this supports the idea that autoimmune diseases involve the body making antibodies against its own parts.

This study showed that when mice are exposed to a specific protein from their own ovaries, their immune system mistakenly makes antibodies against it — even if the ovaries are removed. This proves that autoimmune diseases can happen when the body attacks its own tissues.