It seems the mRNA products are causing the victims to produce IG4 antibodies to the spike.

That sounds innocent enough, a good thing even?

Nah. IG4 are the antibodies used to tell your body that something is harmless and not to react to it. For example some people react terribly to peanuts, whereas most people have IG4 antibodies that will reassure the immune system that "It's just a peanut bro. No worries."

IG4 antibodies on a destructive, replicating virus is almost worst-case-scenario. Worse case is antibody-dependent enhancement (of disease), where your antibodies actually help the virus enter cells. That may well happen too, but dead is dead, and dead is what happens when your immune system tags an invading virus as "It's just a coronavirus bro. No worries."

Note this will likely affect all coronaviruses, so a minor common cold will face no immune resistance, then just replicate forever until it's killed you.

This is the kind of thing that made me not want the mRNA crap in the first place, because a few brave scientists spoke out, and said there's 2 ways this can go. Either you develop an autoimmune disease, where your own immune system attacks parts of you because it caught them making spike proteins, and/or immune system develops a tolerance for the spikes you keep producing, and declares them no biggie.

Both of those results are bad, but the "no biggie" one is the most lethal.

If you're a pureblood thinking "Ha! That'll teach em!" then I suggest you think things through...