Background: The 2019 novel coronavirus (2019-nCoV) has affected more than 72,000 people worldwide and caused more than 1,800 deaths so far. 2019-nCoV uses the angiotensinconverting enzyme 2 (
ACE2 HGNC) as the cell receptor to invade the human host and primarily causes
pneumonia MESHD. Thus,
ACE2 HGNC is the key to understanding the mechanism of
2019-nCoV infection MESHD. Methods: We compared
ACE2 HGNC expression levels across 31 human normal tissues, between males and females, and between younger (ages <= 49 years) and older (ages > 49 years) persons in these tissues. We also investigated the correlations between
ACE2 HGNC expression and immune signatures in various tissues. Results:
ACE2 HGNC expression levels were the highest in small intestine,
testis MESHD, kidney, heart, thyroid, and adipose tissue, and were the lowest in blood, spleen,
bone marrow MESHD, brain, blood vessel, and muscle. In lungs,
colon MESHD, liver, bladder, and adrenal gland,
ACE2 HGNC showed the medium expression levels.
ACE2 HGNC was not differentially expressed between males and females and between younger and older persons in any tissue. In skin, digestive system, brain, and blood vessel,
ACE2 HGNC expression levels were positively associated with immune signatures in both males and females. In thyroid and lungs,
ACE2 HGNC expression levels were positively and negatively associated with immune signatures in males and females, respectively.Conclusions: Our data provide potential cues for the 2019-nCoV epidemic may infect other tissues outside lungs, affect males and females and young and old persons equally, and old age and male are associated with higher mortality risk for
2019-nCoV infection MESHD.