[scarlettzou (OP)]

Lipid nanoparticles are spherical vesicles composed of one (unilamellar) or more (multilamellar) phospholipid bilayers, which are typically composed of four components: cationic lipids, helper lipids, cholesterol CAS #57-88-5 [nofollow], and PEGylated lipids [nofollow](PEG-DMG, PEG-DSPE).
Does the PEG cause an anaphylactic reaction?

[Bored chemist]

Does the PEG cause an anaphylactic reaction?

It can, but that's rare.
https://aacijournal.biomedcentral.com/articles/10.1186/s13223-016-0172-7

[paul cotter]

Many everyday items and foods can trigger anaphylaxis in a susceptible individual. No reason to single out peg, out of all other possible antigens.