What this means, is that the unique ability of this typically rare subclass of antibody to switch out its arms, makes it unable to act out the things that I described above that IgG1 can do. Namely, form immune complexes and bind receptors on cells for removal of unwanted cells. So those three ways: the ADCC, ADCP and CDC - that aid in removal of unwanted cells are all nullified in the scenario where IgG4 is prevalent. Worse than that, since the subclass switch is literally the by-product of continuous antigen stimulation, then this is an immunological endorsement of a ‘win’ for IgG4 if we consider competition for binding sites. In effect, IgG4 outcompetes IgG1 and thus, the scales tip from tumor suppression, to tumor progression. All because of IgG4.
Considering the whispers about increases in reported cancer cases and what have been called "turbo cancers", this mRNA stuff is looking like it has one hell of a curious long tail.