[rddlob]

>Then the virus variant itself would cause autoimmune disease

You clearly have no idea what you are talking about or why the GP comment mentioned an autoimmune disease specifically. mRNA vaccines express specific proteins whereas the virus expresses entire viral molecules. A novel protein expression could cause an autoimmune disease because the novel proteins couls cause the immune system to attack the cells producing the isolated proteins, a problem you wouldnt have with cells producing entire viral bodies.

[harshreality]

I think you misunderstood the (G)GP comment which mentioned cross-reactivity, i.e. the immune system's antibodies cross-reacted with both the spike protein and an endogenous human protein, like what can happen with Epstein–Barr virus Nuclear Antigen-1.

The immune system doesn't generate antibodies to an entire virus. It generates antibodies to specific immunogenic proteins or parts of proteins.

If the spike protein resulting from a vaccine causes an immune response that generates antibodies to the spike protein and oops, also some endogenous human protein, that's autoimmune disease.

If you get infected by a virus with the same spike protein, your body will generate antibodies to the same spike protein and also cause autoimmune disease if the antibodies are cross-reactive.

If cells expressing exogenous immunogenic proteins triggered autoimmune disease[1], even the existing wild-type (alpha variant) vaccines would cause autoimmune disease. Presumably that's not happening. The immune system may attack those cells expressing the exogenous vaccine-coded spike proteins, but normal immune systems down-regulate it well enough that it doesn't cause major problems. It would be a sign of a broken immune system if it decided to initiate a long-term attack of human cells just because they once expressed an immunogenic protein. If it did that, any virus would cause autoimmune disease.

Please tell me you work in a field related to immunology and you have a subtler point that I'm missing, and that you didn't just create an account to criticize a point you misunderstood yourself.

[1] to an unacceptable degree. Obviously, things can go wrong with the immune system and almost anything could, if you're unlucky enough, trigger an immune reaction leading to autoimmune disease eventually.