Table 1.

Studies about macrophages in graft-vs-host disease

Function of macrophage	Macrophage in GVHD	Ref.
Infiltration	Macrophage infiltration contributes to GVHD	[33-36,39,40,44-50,54,56-58,64,65,86,115-118]
Polarization	M1/M2 ratio is increased in acute GVHD	[37,39,61]
	M1/M2 ratio is decreased in chronic GVHD	[45,49,50,86]
	M2 macrophage infiltration contributes to steroid refractory acute GVHD	[40,44]
Recruitment; migration	Recruitment of macrophage to target organs contributes to GVHD	[36,39,48,49,54,117-119]
Cytokine secretion	Macrophage activation with an upregulated expression of cytokines contributes to GVHD	[46,49,55-60,114,116]
Interaction with T cells	Interaction between macrophages and T cells regulates GVHD directly or indirectly	[56,57,60,61,63-66]
Participating in fibrosis	Macrophages attribute to fibrosis in chronic GVHD	[46-50,54,60,86]

GVHD: Graft-vs-host disease; M2: M2 macrophage; M1/M2 ratio: The ratio of M1 macrophage and M2 macrophage.