Analyses of the peripheral immunome following multiple administrations of avelumab, a human IgG1 anti-PD-L1 monoclonal antibody

Table 2 Baseline expression of PD-L1

Classic subsets	Refined subsets	Median % PBMC	Median % parent
PD-L1⁺ CD4		0.08	0.25
	PD-L1⁺ ICOS⁺ CD4	0.05	0.81
	PD-L1⁺ naïve CD4	0.01	0.26
	PD-L1⁺ CM CD4	0.02	0.28
	PD-L1⁺ EM CD4	0.06	0.31
	PD-L1⁺ EMRA CD4	0.01	0.35
PD-L1⁺ CD8		0.04	0.29
	PD-L1⁺ naïve CD8	<0.01	0.40
	PD-L1⁺ CM CD8	<0.01	0.41
	PD-L1⁺ EM CD8	0.02	0.26
	PD-L1⁺ EMRA CD8	0.01	0.30
PD-L1⁺ Tregs		<0.01	0.38
PD-L1⁺ NK		0.06	1.03
	PD-L1⁺ mature NK	0.04	0.97
	PD-L1⁺ functional intermediate NK	<0.01	0.31
	PD-L1⁺ immature NK	<0.01	0.66
	PD-L1⁺ unconventional NK	0.02	5.58
PD-L1⁺ NK-T		0.03	1.34
PD-L1⁺ B cells		0.88	11.22
PD-L¹⁺ cDC		0.02	7.12
PD-L1⁺ pDC		0.02	9.85
PD-L1⁺ MDSC		0.71	16.54
	PD-L1⁺ mMDSC	0.10	4.81
	PD-L1⁺ gMDSC	0.26	35.77
	PD-L1⁺ lin neg MDSC	0.17	18.75

In 28 patients prior to avelumab therapy, expression of PD-L1 was measured by flow cytometry in 9 classic subsets and 16 refined subsets as both percentage of total PBMC and of parental cell type
cDC conventional dendritic cells, CM central memory, EM effector memory, EMRA terminally differentiated effector memory, gMDSC granulocytic MDSC, ICOS inducible T cell co-stimulator, lin neg MDSCs lineage negative MDSCs, MDSC myeloid derived suppressor cell, mMDSC monocytic MDSC, NK natural killer, pDC plasmacytoid DC, PD-L1 programmed cell death ligand-1, Tregs regulatory T cells