Is the distinction between “Fishbane” and “non-Fishbane” complement-mediated reactions largely semantic?

Mechanistically, they’re on the same spectrum

• Both so-called Fishbane and non-Fishbane reactions:
  • Occur within minutes of starting IV iron.
  • Are non-IgE, complement-driven, innate immune events.
  • Are rate-dependent and idiosyncratic.
  • Share the same core mechanism: transient C3a/C5a generation leading to vasodilation, tachycardia, dyspnea, and anxiety.
  • The only real difference is the magnitude of this activation and the extent of physiologic response.

So mechanistically, they are not two different entities—just different magnitudes of the same process. Same mechanism, different intensity

There’s no hard mechanistic line between a “Fishbane reaction” and a “non-Fishbane CARPA reaction.” The difference is operational, not biologic.