. Author manuscript; available in PMC: 2016 Jul 1.

Published in final edited form as: Transfusion. 2015 Jul;55(0):S47–S58. doi: 10.1111/trf.13147

Table 1.

Examples for molecules involved in the bonding between RBC and monocytes/macrophages

Receptor on monocytes/macrophages^*	Proteins that can be bound to the RBC surface
Fc	IgG₁, IgG₃, IgA, possibly IgG₂
CR1	C3b, iC3b^†
CR3	iC3b
CR4	iC3b

Monocytes, floating in the blood stream (intravascular), and macrophages, residing in tissues (extravascular), are the same cell type.

^†

iC3b is an inactive derivative of C3b and degrades to C3d,g, which is the last step in vivo and can remain attached to the RBC surface for the rest of the RBC’s life span. In vitro, C3d,g can be further cleaved, using trypsin, to C3d.⁴

Fc – Fc-receptors. They exist in variations.¹⁵

CR1 – complement receptor 1, CD35, blood group system Knops

CR3 – complement receptor 3, CD11b + CD18, integrin alpha-M

CR4 – complement receptor 4, DC11c + CD18, intergrin alpha-X