Table 2.

Summary of Cell Expression of ACE2 and TMPRSS2

Authors	Samples	Tissue	Cell types	ACE2	TMPRSS2
Bilinska [14]	Mouse	Olfactory	Sustentatorial	+	+
Brann [15]	Human & Mouse	Olfactory	Sustentatorial	+	+
			Neuronal	-	-
			Stem Neuronal	+	+
Butowt [16]	Human & Mouse	Nasal	Epithelial	+	+
		Olfactory	Sustentatorial	+	−
			Neuronal	−	−
Chen [18]	Human	Major Salivary Gland	Granular	+	NA
Hamming [11]	Human	Oral, Nasal, Nasopharyngeal	Basal layer	+	NA
			Endothelial	+	NA
Hikmet [19]	Human	Nasopharyngeal	Epithelial	−	NA
Jia [12]	Human		Apical Epithelial	+	NA
			Endothelial	+	NA
Lee [20]	Human	Tracheal, Nasal, Sinusal	Apical Epithelial	+	NA
			Goblet	−	NA
Li [21]	Human	Thyroid	Unspecified	+	NA
Liu [13]	Monkey	Pharyngeal	Minor salivary ductal	+	NA
		Tracheal	Basal layer	+	NA
Sungnak [22]	Human	Tracheal & Nasal	Goblet	+	+
			Apical Epithelial	+	+
Vaarala [10]	Human & Mouse	Major Salivary Gland	Unspecified	NA	+
Xu [23]	Human	Oral	Apical Epithelial	+	NA
			Fibroblast	+	NA
			T- and B-cells	+	NA
Xu [24]	Human	Minor Salivary Gland	Unspecified	+	NA
Wu [25]	Human	Nasal	Unspecified	+	NA
		Oral	Basal layer	+	NA
Ziegler [26]	Human, Mouse &	Nasal & Sinusal	Goblet	+	+
	Monkey

ACE2 Angiotensin Converting Enzyme-2, NA not available, TMPRSS2 transmembrane protease serine-2